SPC Severe Thunderstorm Watch 631
WW 631 SEVERE TSTM CA OR WA 172020Z - 180400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 631 NWS Storm Prediction Center Norman OK 120 PM PDT Sat Aug 17 2024 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northern California Western Oregon Southwest Washington * Effective this Saturday afternoon and evening from 120 PM until 900 PM PDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Scattered large hail events to 1.5 inches in diameter possible SUMMARY...Thunderstorms will intensify this afternoon along and west of the Cascade Range, tracking northward across the watch area. A few severe storms are expected, capable of large hail and locally damaging wind gusts. The severe thunderstorm watch area is approximately along and 35 statute miles east and west of a line from 65 miles south southwest of Mount Shasta CA to 60 miles north northeast of Portland OR. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU1). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 630... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 20030. ...Hart Read more
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 631 NWS Storm Prediction Center Norman OK 120 PM PDT Sat Aug 17 2024 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northern California Western Oregon Southwest Washington * Effective this Saturday afternoon and evening from 120 PM until 900 PM PDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Scattered large hail events to 1.5 inches in diameter possible SUMMARY...Thunderstorms will intensify this afternoon along and west of the Cascade Range, tracking northward across the watch area. A few severe storms are expected, capable of large hail and locally damaging wind gusts. The severe thunderstorm watch area is approximately along and 35 statute miles east and west of a line from 65 miles south southwest of Mount Shasta CA to 60 miles north northeast of Portland OR. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU1). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 630... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 20030. ...Hart Read more
SPC Aug 17, 2024 2000 UTC Day 1 Convective Outlook
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Sat Aug 17 2024 Valid 172000Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CASCADES AND COLUMBIA BASIN...PARTS OF UTAH...AND IN THE OHIO/TENNESSEE VALLEYS... ...SUMMARY... Scattered severe thunderstorms are possible through tonight in vicinity of the Ohio Valley, Utah and the Cascades of Oregon and Washington. Wind and isolated hail are the primary threats. ...20z Update... The forecast remains largely on track with on minor changes. Strong to severe storms ongoing over the OH Valley and eastern US will remain capable of isolated damaging gusts through this evening. Scattered severe storms are also expected to develop over the Cascades and Columbia Basin later this afternoon and into the overnight hours with a risk for danging winds and hail. ...Tennessee Valley and southern Appalachians.... Multiple bands and clusters of strong to occasional severe storms are ongoing this afternoon ahead of the broad upper trough and slow moving cold front. Recent VAD observations from HTX and MRX show a belt of stronger mid-level flow has extend over parts of the eastern TN Valley and Southern Appalachians supporting greater deep-layer shear of 25-30 kt. Colocated with a hot and seasonably moist/unstable air mass, a cluster of more organized/robust convection being observed over part of northern AL and southern TN may continue east/southeast into parts of northern GA and the western Carolinas this afternoon/evening. A mix of persistent multi-cell clusters and transient supercell structures would support a risk for damaging winds and isolated hail. Have upgraded to level 2 categorical Slight to better account for the risk of damaging winds with this cluster of stronger storms. ...Utah... Ahead of a convective enhanced shortwave trough, scattered strong to severe thunderstorms should continue this afternoon and into the evening hours with a risk for damaging winds and occasional hail. Confidence in the highest threat corridor remains across parts of central UT where greater diurnal heating has allowed for moderate destabilization. The exact eastern extent of organized convective potential is somewhat nebulous given the limited buoyancy and expected degree of storm coverage. However, at least some risk for damaging gusts will be possible with high-based showers and storms over eastern UT. Have modified the eastern edge of the level-2 Slight Risk to better reflect the potential for organized storms with wind gust and hail potential later this afternoon. Otherwise, see the prior discussion for additional information. ..Lyons.. 08/17/2024 .PREV DISCUSSION... /ISSUED 1121 AM CDT Sat Aug 17 2024/ ...CA/OR/WA... Morning water vapor loop shows a strong and fast-moving shortwave trough approaching the coast of northern CA. This feature will rotate inland, affecting the Cascades region this afternoon and evening. Steep mid level lapse rates and pockets of MLCAPE of 500-1000 J/kg will aid in the development of scattered thunderstorms by early afternoon over the mountains and coastal ranges of northern CA, building quickly northward into southern/central OR. Winds aloft will be strenghtening during this period, allowing a few supercell storm structures to likely develop. These storms may pose a threat of large hail and locally damaging wind gusts through the afternoon as they track northward into WA. Other high-based storms capable of gusty/damaging winds may affect parts of the Columbia Basin of northern OR/central WA as well. ...UT... A compact shortwave trough over central NV will continue to rotate around the Four-Corners upper ridge into UT today. Considerable coverage of afternoon thunderstorms will likely accompany this system. Winds aloft will be relatively strong, favoring faster-moving organized multicell or occasional supercell structures capable of damaging winds and hail. One forecast uncertainty is the extent of morning cloudiness and its impact on afternoon destabilization. Regardless, at least isolated severe storms are expected, with some threat spreading into southwest WY by evening. ...Eastern US... A broad upper trough will affect much of the eastern US today, with clusters of thunderstorms from NY/PA across the Appalachians into the Mid South. Any of these clusters may occasionally pose a risk of locally gusty/damaging wind gusts or hail. However, perhaps a more focused area of concern will extend from northern TN into southern OH. The axis of the mid level speed max (~40 knots) will spread across this area during the afternoon. CAM guidance has been consistent on suggesting a higher confidence in a few intense cells in this region. Read more
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Sat Aug 17 2024 Valid 172000Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CASCADES AND COLUMBIA BASIN...PARTS OF UTAH...AND IN THE OHIO/TENNESSEE VALLEYS... ...SUMMARY... Scattered severe thunderstorms are possible through tonight in vicinity of the Ohio Valley, Utah and the Cascades of Oregon and Washington. Wind and isolated hail are the primary threats. ...20z Update... The forecast remains largely on track with on minor changes. Strong to severe storms ongoing over the OH Valley and eastern US will remain capable of isolated damaging gusts through this evening. Scattered severe storms are also expected to develop over the Cascades and Columbia Basin later this afternoon and into the overnight hours with a risk for danging winds and hail. ...Tennessee Valley and southern Appalachians.... Multiple bands and clusters of strong to occasional severe storms are ongoing this afternoon ahead of the broad upper trough and slow moving cold front. Recent VAD observations from HTX and MRX show a belt of stronger mid-level flow has extend over parts of the eastern TN Valley and Southern Appalachians supporting greater deep-layer shear of 25-30 kt. Colocated with a hot and seasonably moist/unstable air mass, a cluster of more organized/robust convection being observed over part of northern AL and southern TN may continue east/southeast into parts of northern GA and the western Carolinas this afternoon/evening. A mix of persistent multi-cell clusters and transient supercell structures would support a risk for damaging winds and isolated hail. Have upgraded to level 2 categorical Slight to better account for the risk of damaging winds with this cluster of stronger storms. ...Utah... Ahead of a convective enhanced shortwave trough, scattered strong to severe thunderstorms should continue this afternoon and into the evening hours with a risk for damaging winds and occasional hail. Confidence in the highest threat corridor remains across parts of central UT where greater diurnal heating has allowed for moderate destabilization. The exact eastern extent of organized convective potential is somewhat nebulous given the limited buoyancy and expected degree of storm coverage. However, at least some risk for damaging gusts will be possible with high-based showers and storms over eastern UT. Have modified the eastern edge of the level-2 Slight Risk to better reflect the potential for organized storms with wind gust and hail potential later this afternoon. Otherwise, see the prior discussion for additional information. ..Lyons.. 08/17/2024 .PREV DISCUSSION... /ISSUED 1121 AM CDT Sat Aug 17 2024/ ...CA/OR/WA... Morning water vapor loop shows a strong and fast-moving shortwave trough approaching the coast of northern CA. This feature will rotate inland, affecting the Cascades region this afternoon and evening. Steep mid level lapse rates and pockets of MLCAPE of 500-1000 J/kg will aid in the development of scattered thunderstorms by early afternoon over the mountains and coastal ranges of northern CA, building quickly northward into southern/central OR. Winds aloft will be strenghtening during this period, allowing a few supercell storm structures to likely develop. These storms may pose a threat of large hail and locally damaging wind gusts through the afternoon as they track northward into WA. Other high-based storms capable of gusty/damaging winds may affect parts of the Columbia Basin of northern OR/central WA as well. ...UT... A compact shortwave trough over central NV will continue to rotate around the Four-Corners upper ridge into UT today. Considerable coverage of afternoon thunderstorms will likely accompany this system. Winds aloft will be relatively strong, favoring faster-moving organized multicell or occasional supercell structures capable of damaging winds and hail. One forecast uncertainty is the extent of morning cloudiness and its impact on afternoon destabilization. Regardless, at least isolated severe storms are expected, with some threat spreading into southwest WY by evening. ...Eastern US... A broad upper trough will affect much of the eastern US today, with clusters of thunderstorms from NY/PA across the Appalachians into the Mid South. Any of these clusters may occasionally pose a risk of locally gusty/damaging wind gusts or hail. However, perhaps a more focused area of concern will extend from northern TN into southern OH. The axis of the mid level speed max (~40 knots) will spread across this area during the afternoon. CAM guidance has been consistent on suggesting a higher confidence in a few intense cells in this region. Read more
SPC Aug 17, 2024 2000 UTC Day 1 Convective Outlook
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Sat Aug 17 2024 Valid 172000Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CASCADES AND COLUMBIA BASIN...PARTS OF UTAH...AND IN THE OHIO/TENNESSEE VALLEYS... ...SUMMARY... Scattered severe thunderstorms are possible through tonight in vicinity of the Ohio Valley, Utah and the Cascades of Oregon and Washington. Wind and isolated hail are the primary threats. ...20z Update... The forecast remains largely on track with on minor changes. Strong to severe storms ongoing over the OH Valley and eastern US will remain capable of isolated damaging gusts through this evening. Scattered severe storms are also expected to develop over the Cascades and Columbia Basin later this afternoon and into the overnight hours with a risk for danging winds and hail. ...Tennessee Valley and southern Appalachians.... Multiple bands and clusters of strong to occasional severe storms are ongoing this afternoon ahead of the broad upper trough and slow moving cold front. Recent VAD observations from HTX and MRX show a belt of stronger mid-level flow has extend over parts of the eastern TN Valley and Southern Appalachians supporting greater deep-layer shear of 25-30 kt. Colocated with a hot and seasonably moist/unstable air mass, a cluster of more organized/robust convection being observed over part of northern AL and southern TN may continue east/southeast into parts of northern GA and the western Carolinas this afternoon/evening. A mix of persistent multi-cell clusters and transient supercell structures would support a risk for damaging winds and isolated hail. Have upgraded to level 2 categorical Slight to better account for the risk of damaging winds with this cluster of stronger storms. ...Utah... Ahead of a convective enhanced shortwave trough, scattered strong to severe thunderstorms should continue this afternoon and into the evening hours with a risk for damaging winds and occasional hail. Confidence in the highest threat corridor remains across parts of central UT where greater diurnal heating has allowed for moderate destabilization. The exact eastern extent of organized convective potential is somewhat nebulous given the limited buoyancy and expected degree of storm coverage. However, at least some risk for damaging gusts will be possible with high-based showers and storms over eastern UT. Have modified the eastern edge of the level-2 Slight Risk to better reflect the potential for organized storms with wind gust and hail potential later this afternoon. Otherwise, see the prior discussion for additional information. ..Lyons.. 08/17/2024 .PREV DISCUSSION... /ISSUED 1121 AM CDT Sat Aug 17 2024/ ...CA/OR/WA... Morning water vapor loop shows a strong and fast-moving shortwave trough approaching the coast of northern CA. This feature will rotate inland, affecting the Cascades region this afternoon and evening. Steep mid level lapse rates and pockets of MLCAPE of 500-1000 J/kg will aid in the development of scattered thunderstorms by early afternoon over the mountains and coastal ranges of northern CA, building quickly northward into southern/central OR. Winds aloft will be strenghtening during this period, allowing a few supercell storm structures to likely develop. These storms may pose a threat of large hail and locally damaging wind gusts through the afternoon as they track northward into WA. Other high-based storms capable of gusty/damaging winds may affect parts of the Columbia Basin of northern OR/central WA as well. ...UT... A compact shortwave trough over central NV will continue to rotate around the Four-Corners upper ridge into UT today. Considerable coverage of afternoon thunderstorms will likely accompany this system. Winds aloft will be relatively strong, favoring faster-moving organized multicell or occasional supercell structures capable of damaging winds and hail. One forecast uncertainty is the extent of morning cloudiness and its impact on afternoon destabilization. Regardless, at least isolated severe storms are expected, with some threat spreading into southwest WY by evening. ...Eastern US... A broad upper trough will affect much of the eastern US today, with clusters of thunderstorms from NY/PA across the Appalachians into the Mid South. Any of these clusters may occasionally pose a risk of locally gusty/damaging wind gusts or hail. However, perhaps a more focused area of concern will extend from northern TN into southern OH. The axis of the mid level speed max (~40 knots) will spread across this area during the afternoon. CAM guidance has been consistent on suggesting a higher confidence in a few intense cells in this region. Read more
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Sat Aug 17 2024 Valid 172000Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CASCADES AND COLUMBIA BASIN...PARTS OF UTAH...AND IN THE OHIO/TENNESSEE VALLEYS... ...SUMMARY... Scattered severe thunderstorms are possible through tonight in vicinity of the Ohio Valley, Utah and the Cascades of Oregon and Washington. Wind and isolated hail are the primary threats. ...20z Update... The forecast remains largely on track with on minor changes. Strong to severe storms ongoing over the OH Valley and eastern US will remain capable of isolated damaging gusts through this evening. Scattered severe storms are also expected to develop over the Cascades and Columbia Basin later this afternoon and into the overnight hours with a risk for danging winds and hail. ...Tennessee Valley and southern Appalachians.... Multiple bands and clusters of strong to occasional severe storms are ongoing this afternoon ahead of the broad upper trough and slow moving cold front. Recent VAD observations from HTX and MRX show a belt of stronger mid-level flow has extend over parts of the eastern TN Valley and Southern Appalachians supporting greater deep-layer shear of 25-30 kt. Colocated with a hot and seasonably moist/unstable air mass, a cluster of more organized/robust convection being observed over part of northern AL and southern TN may continue east/southeast into parts of northern GA and the western Carolinas this afternoon/evening. A mix of persistent multi-cell clusters and transient supercell structures would support a risk for damaging winds and isolated hail. Have upgraded to level 2 categorical Slight to better account for the risk of damaging winds with this cluster of stronger storms. ...Utah... Ahead of a convective enhanced shortwave trough, scattered strong to severe thunderstorms should continue this afternoon and into the evening hours with a risk for damaging winds and occasional hail. Confidence in the highest threat corridor remains across parts of central UT where greater diurnal heating has allowed for moderate destabilization. The exact eastern extent of organized convective potential is somewhat nebulous given the limited buoyancy and expected degree of storm coverage. However, at least some risk for damaging gusts will be possible with high-based showers and storms over eastern UT. Have modified the eastern edge of the level-2 Slight Risk to better reflect the potential for organized storms with wind gust and hail potential later this afternoon. Otherwise, see the prior discussion for additional information. ..Lyons.. 08/17/2024 .PREV DISCUSSION... /ISSUED 1121 AM CDT Sat Aug 17 2024/ ...CA/OR/WA... Morning water vapor loop shows a strong and fast-moving shortwave trough approaching the coast of northern CA. This feature will rotate inland, affecting the Cascades region this afternoon and evening. Steep mid level lapse rates and pockets of MLCAPE of 500-1000 J/kg will aid in the development of scattered thunderstorms by early afternoon over the mountains and coastal ranges of northern CA, building quickly northward into southern/central OR. Winds aloft will be strenghtening during this period, allowing a few supercell storm structures to likely develop. These storms may pose a threat of large hail and locally damaging wind gusts through the afternoon as they track northward into WA. Other high-based storms capable of gusty/damaging winds may affect parts of the Columbia Basin of northern OR/central WA as well. ...UT... A compact shortwave trough over central NV will continue to rotate around the Four-Corners upper ridge into UT today. Considerable coverage of afternoon thunderstorms will likely accompany this system. Winds aloft will be relatively strong, favoring faster-moving organized multicell or occasional supercell structures capable of damaging winds and hail. One forecast uncertainty is the extent of morning cloudiness and its impact on afternoon destabilization. Regardless, at least isolated severe storms are expected, with some threat spreading into southwest WY by evening. ...Eastern US... A broad upper trough will affect much of the eastern US today, with clusters of thunderstorms from NY/PA across the Appalachians into the Mid South. Any of these clusters may occasionally pose a risk of locally gusty/damaging wind gusts or hail. However, perhaps a more focused area of concern will extend from northern TN into southern OH. The axis of the mid level speed max (~40 knots) will spread across this area during the afternoon. CAM guidance has been consistent on suggesting a higher confidence in a few intense cells in this region. Read more
SPC Day 2 Fire Weather Outlook
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0232 PM CDT Sat Aug 17 2024 Valid 181200Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHWEST NEVADA... A critical area has been added to southwest Nevada with this update. Here, conditions tomorrow (Sunday) should be similar to today (Saturday). Relative humidity should fall below 10% over a sizeable portion of the area, with numerical guidance indicating increasing confidence of winds in the afternoon approaching 20 mph. Elsewhere, the forecast remains on track. ..Marsh.. 08/17/2024 .PREV DISCUSSION... /ISSUED 0153 AM CDT Sat Aug 17 2024/ ...Synopsis... A mid-level trough will continue to meander along the West Coast while upper ridging persists across the central U.S. tomorrow (Sunday). A 500 mb speed max within the upper trough should progress northward toward the Pacific Northwest and International border, with a gradual weakening in isallobaric flow expected to the lee of the Cascades and Sierra. Nonetheless, boundary-layer mixing will promote Elevated dry and breezy conditions in terrain-favoring locations east of the Sierra into the Great Basin by afternoon, where Elevated highlights have been introduced. ...Please see www.spc.noaa.gov/fire for graphic product... Read more
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0232 PM CDT Sat Aug 17 2024 Valid 181200Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHWEST NEVADA... A critical area has been added to southwest Nevada with this update. Here, conditions tomorrow (Sunday) should be similar to today (Saturday). Relative humidity should fall below 10% over a sizeable portion of the area, with numerical guidance indicating increasing confidence of winds in the afternoon approaching 20 mph. Elsewhere, the forecast remains on track. ..Marsh.. 08/17/2024 .PREV DISCUSSION... /ISSUED 0153 AM CDT Sat Aug 17 2024/ ...Synopsis... A mid-level trough will continue to meander along the West Coast while upper ridging persists across the central U.S. tomorrow (Sunday). A 500 mb speed max within the upper trough should progress northward toward the Pacific Northwest and International border, with a gradual weakening in isallobaric flow expected to the lee of the Cascades and Sierra. Nonetheless, boundary-layer mixing will promote Elevated dry and breezy conditions in terrain-favoring locations east of the Sierra into the Great Basin by afternoon, where Elevated highlights have been introduced. ...Please see www.spc.noaa.gov/fire for graphic product... Read more
SPC Day 2 Fire Weather Outlook
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0232 PM CDT Sat Aug 17 2024 Valid 181200Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHWEST NEVADA... A critical area has been added to southwest Nevada with this update. Here, conditions tomorrow (Sunday) should be similar to today (Saturday). Relative humidity should fall below 10% over a sizeable portion of the area, with numerical guidance indicating increasing confidence of winds in the afternoon approaching 20 mph. Elsewhere, the forecast remains on track. ..Marsh.. 08/17/2024 .PREV DISCUSSION... /ISSUED 0153 AM CDT Sat Aug 17 2024/ ...Synopsis... A mid-level trough will continue to meander along the West Coast while upper ridging persists across the central U.S. tomorrow (Sunday). A 500 mb speed max within the upper trough should progress northward toward the Pacific Northwest and International border, with a gradual weakening in isallobaric flow expected to the lee of the Cascades and Sierra. Nonetheless, boundary-layer mixing will promote Elevated dry and breezy conditions in terrain-favoring locations east of the Sierra into the Great Basin by afternoon, where Elevated highlights have been introduced. ...Please see www.spc.noaa.gov/fire for graphic product... Read more
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0232 PM CDT Sat Aug 17 2024 Valid 181200Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHWEST NEVADA... A critical area has been added to southwest Nevada with this update. Here, conditions tomorrow (Sunday) should be similar to today (Saturday). Relative humidity should fall below 10% over a sizeable portion of the area, with numerical guidance indicating increasing confidence of winds in the afternoon approaching 20 mph. Elsewhere, the forecast remains on track. ..Marsh.. 08/17/2024 .PREV DISCUSSION... /ISSUED 0153 AM CDT Sat Aug 17 2024/ ...Synopsis... A mid-level trough will continue to meander along the West Coast while upper ridging persists across the central U.S. tomorrow (Sunday). A 500 mb speed max within the upper trough should progress northward toward the Pacific Northwest and International border, with a gradual weakening in isallobaric flow expected to the lee of the Cascades and Sierra. Nonetheless, boundary-layer mixing will promote Elevated dry and breezy conditions in terrain-favoring locations east of the Sierra into the Great Basin by afternoon, where Elevated highlights have been introduced. ...Please see www.spc.noaa.gov/fire for graphic product... Read more
SPC Aug 17, 2024 1930 UTC Day 3 Severe Thunderstorm Outlook
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Sat Aug 17 2024 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE NORTHERN/CENTRAL HIGH PLAINS...THE LOWER MID-ATLANTIC...AND THE SABINE VALLEY... ...SUMMARY... Isolated severe storms are possible across parts of the northern Great Plains to central High Plains, the Lower Mid-Atlantic States, and the Sabine Valley on Monday afternoon into the evening. ...Central High to northern Great Plains... A mid/upper trough should stall near the WA/southern BC coast, while a downstream ridge flattens/drifts east from the central High Plains to the Dakotas. As these processes occur, the meridional flow regime over the Northwest should evolve into predominant southwesterlies, with some enhancement relative to Sunday in the lee of northern Rockies. Fairly extensive convective coverage is likely towards mid to late afternoon as storms develop off the higher terrain within a broad plume of adequate 700-mb moisture and seasonably rich boundary-layer dew points across the northern/central High Plains. Deep-layer shear, especially with east and south extent, will be relatively modest. This suggests loosely to semi-organized clusters should dominate with isolated severe gusts as the primary threat. Localized severe hail is also possible, especially within the peak buoyancy axis across eastern MT to the Dakotas border area. ...Lower Mid-Atlantic... A large-scale mid/upper trough will drift east across southeast Canada to the South Atlantic coast. While severe potential appears to be less than on Sunday, embedded shortwave impulses and boundary-layer heating of a still richly moist air mass should support afternoon scattered thunderstorms focused on the Mid-Atlantic States into NC. A modest combination of deep-layer shear and MLCAPE should yield a threat for sporadic strong gusts. This may yield localized tree damage, peaking in the late afternoon. ...Sabine Valley... A conditionally adequate environment for a few marginally severe storms remains apparent along a persistent baroclinic/differential heating zone from the Lower Red River to Sabine Valleys. Bulk of guidance, outside of the 12Z GFS/GEFS, suggest convective potential should remain rather isolated inland of the Gulf Coast. If surface-based storms can be sustained, the western fringe of moderate north-northwesterly mid-level flow would foster potential for a few strong downbursts and small hail. ..Grams.. 08/17/2024 Read more
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Sat Aug 17 2024 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE NORTHERN/CENTRAL HIGH PLAINS...THE LOWER MID-ATLANTIC...AND THE SABINE VALLEY... ...SUMMARY... Isolated severe storms are possible across parts of the northern Great Plains to central High Plains, the Lower Mid-Atlantic States, and the Sabine Valley on Monday afternoon into the evening. ...Central High to northern Great Plains... A mid/upper trough should stall near the WA/southern BC coast, while a downstream ridge flattens/drifts east from the central High Plains to the Dakotas. As these processes occur, the meridional flow regime over the Northwest should evolve into predominant southwesterlies, with some enhancement relative to Sunday in the lee of northern Rockies. Fairly extensive convective coverage is likely towards mid to late afternoon as storms develop off the higher terrain within a broad plume of adequate 700-mb moisture and seasonably rich boundary-layer dew points across the northern/central High Plains. Deep-layer shear, especially with east and south extent, will be relatively modest. This suggests loosely to semi-organized clusters should dominate with isolated severe gusts as the primary threat. Localized severe hail is also possible, especially within the peak buoyancy axis across eastern MT to the Dakotas border area. ...Lower Mid-Atlantic... A large-scale mid/upper trough will drift east across southeast Canada to the South Atlantic coast. While severe potential appears to be less than on Sunday, embedded shortwave impulses and boundary-layer heating of a still richly moist air mass should support afternoon scattered thunderstorms focused on the Mid-Atlantic States into NC. A modest combination of deep-layer shear and MLCAPE should yield a threat for sporadic strong gusts. This may yield localized tree damage, peaking in the late afternoon. ...Sabine Valley... A conditionally adequate environment for a few marginally severe storms remains apparent along a persistent baroclinic/differential heating zone from the Lower Red River to Sabine Valleys. Bulk of guidance, outside of the 12Z GFS/GEFS, suggest convective potential should remain rather isolated inland of the Gulf Coast. If surface-based storms can be sustained, the western fringe of moderate north-northwesterly mid-level flow would foster potential for a few strong downbursts and small hail. ..Grams.. 08/17/2024 Read more
SPC - No watches are valid as of Sat Aug 17 17:55:02 UTC 2024
No watches are valid as of Sat Aug 17 17:55:02 UTC 2024.
SPC MD 1930
MD 1930 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR SOUTHERN OHIO...CENTRAL KENTUCKY...NORTHERN MIDDLE TENNESSEE
Mesoscale Discussion 1930 NWS Storm Prediction Center Norman OK 1231 PM CDT Sat Aug 17 2024 Areas affected...Southern Ohio...Central Kentucky...Northern Middle Tennessee Concerning...Severe potential...Watch possible Valid 171731Z - 171930Z Probability of Watch Issuance...40 percent SUMMARY...Strong to severe storms capable of damaging wind to increase in cover through the afternoon/evening. DISCUSSION...An increase in cumulus development is noted in visible satellite across portions of central Kentucky along and ahead of an approaching cold front across IL/IN. A cluster of elevated convection continues to move across areas north of Lexington, with objective analysis still indicated some MLCIN may remain in place across the region. Additional cells are also developing north of Bowling Green. Daytime heating has led to temperatures in the upper 80s to 90s, with MLCAPE around 2500-3000 J/kg. As a mid-level speed max and large scale forcing spreads across this region this afternoon, further thunderstorm development is expected to continue through the afternoon and evening, with potential for locally gusty/damaging winds. Should storms intensify, a watch may be needed to cover this threat later in the afternoon. ..Thornton/Hart.. 08/17/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...RLX...JKL...ILN...LMK...OHX... LAT...LON 37098680 38078585 38908464 39628358 39688276 39618272 38988277 38518290 38088303 36738459 36208583 36688694 37098680 Read more
Mesoscale Discussion 1930 NWS Storm Prediction Center Norman OK 1231 PM CDT Sat Aug 17 2024 Areas affected...Southern Ohio...Central Kentucky...Northern Middle Tennessee Concerning...Severe potential...Watch possible Valid 171731Z - 171930Z Probability of Watch Issuance...40 percent SUMMARY...Strong to severe storms capable of damaging wind to increase in cover through the afternoon/evening. DISCUSSION...An increase in cumulus development is noted in visible satellite across portions of central Kentucky along and ahead of an approaching cold front across IL/IN. A cluster of elevated convection continues to move across areas north of Lexington, with objective analysis still indicated some MLCIN may remain in place across the region. Additional cells are also developing north of Bowling Green. Daytime heating has led to temperatures in the upper 80s to 90s, with MLCAPE around 2500-3000 J/kg. As a mid-level speed max and large scale forcing spreads across this region this afternoon, further thunderstorm development is expected to continue through the afternoon and evening, with potential for locally gusty/damaging winds. Should storms intensify, a watch may be needed to cover this threat later in the afternoon. ..Thornton/Hart.. 08/17/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...RLX...JKL...ILN...LMK...OHX... LAT...LON 37098680 38078585 38908464 39628358 39688276 39618272 38988277 38518290 38088303 36738459 36208583 36688694 37098680 Read more
SPC MD 1931
MD 1931 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR NORTHWEST ARIZONA TO NORTH-CENTRAL UTAH
Mesoscale Discussion 1931 NWS Storm Prediction Center Norman OK 1252 PM CDT Sat Aug 17 2024 Areas affected...northwest Arizona to north-central Utah Concerning...Severe potential...Watch possible Valid 171752Z - 171945Z Probability of Watch Issuance...60 percent SUMMARY...Severe wind gusts are possible with high-based storms this afternoon and evening from northwest Arizona to north-central Utah. DISCUSSION...Numerous elevated thunderstorms developed earlier this morning on the leading edge of a northward surge of monsoon moisture. In the wake of this convection, clear skies have allowed for sufficient surface heating which, when combined with the increasing low-level moisture, has resulted in moderate destabilization. SPC mesoanalysis suggests inhibition has mostly eroded. Therefore, surface-based storms, with likely a greater severe wind threat, are possible within the next 1 to 2 hours as further warming/moistening occurs. An environment this afternoon featuring high-based storms and a deeply-mixed boundary layer with 1000-1500 J/kg MLCAPE and 25-30 knots of effective shear should support some threat for severe wind gusts. With multiple rounds of storms possible, a severe thunderstorm watch may be needed to address this threat. ..Bentley/Hart.. 08/17/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGZ...SLC...VEF... LAT...LON 36591423 38751377 39551345 40181302 40531196 40271123 38711119 37291165 36821196 35861252 35711307 36181375 36591423 Read more
Mesoscale Discussion 1931 NWS Storm Prediction Center Norman OK 1252 PM CDT Sat Aug 17 2024 Areas affected...northwest Arizona to north-central Utah Concerning...Severe potential...Watch possible Valid 171752Z - 171945Z Probability of Watch Issuance...60 percent SUMMARY...Severe wind gusts are possible with high-based storms this afternoon and evening from northwest Arizona to north-central Utah. DISCUSSION...Numerous elevated thunderstorms developed earlier this morning on the leading edge of a northward surge of monsoon moisture. In the wake of this convection, clear skies have allowed for sufficient surface heating which, when combined with the increasing low-level moisture, has resulted in moderate destabilization. SPC mesoanalysis suggests inhibition has mostly eroded. Therefore, surface-based storms, with likely a greater severe wind threat, are possible within the next 1 to 2 hours as further warming/moistening occurs. An environment this afternoon featuring high-based storms and a deeply-mixed boundary layer with 1000-1500 J/kg MLCAPE and 25-30 knots of effective shear should support some threat for severe wind gusts. With multiple rounds of storms possible, a severe thunderstorm watch may be needed to address this threat. ..Bentley/Hart.. 08/17/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGZ...SLC...VEF... LAT...LON 36591423 38751377 39551345 40181302 40531196 40271123 38711119 37291165 36821196 35861252 35711307 36181375 36591423 Read more
SPC Aug 17, 2024 1730 UTC Day 2 Convective Outlook
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sat Aug 17 2024 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE DEEP SOUTH TO THE MID-ATLANTIC STATES... ...SUMMARY... Scattered wind damage will be possible from the Mid-Atlantic States to the Deep South from mid-afternoon to early evening on Sunday. ...Deep South to the Mid-Atlantic States... A persistent, slow-moving mid/upper trough from the eastern Great Lakes to the southern Appalachians should amplify slightly as a mid/upper jetlet digs into the basal portion of the trough. This will result in the belt of enhanced northwesterly to west-southwesterly mid-level flow becoming centered across the Southeast by Sunday afternoon. Occluded surface cyclone should drift east across southern ON into western NY. An arcing cold front will largely extend south across the Mid-Atlantic to Southeast before trailing westward over the Deep South to Lower MS Valley. Hot temperatures from 95-103 F are expected at peak heating along the trailing portion of the front west of the Carolinas. This should yield moderate to large buoyancy amid moderate northwesterly deep-layer shear. Isolated to scattered thunderstorm development is anticipated towards late afternoon along the weakly convergent front. While severe hail is possible, the rather warm thermodynamic profile should largely support a primary threat of scattered damaging winds from strong to severe wind gusts. Confidence is below average in where south-southeast moving clusters should develop, so have maintained a broad level 2-SLGT risk despite some embedded areas likely not having thunder occur. Convective coverage may become widespread across parts of the Lower Mid-Atlantic States where larger-scale ascent with stronger low-level convergence is expected. Although deep-layer shear should be comparatively weaker along with poor mid-level lapse rates, rich boundary-layer moisture and adequate heating should be sufficient for a scattered wind damage threat. Strong to localized severe gusts with slow, eastward-moving multicell clusters will be possible, and the level 2-SLGT risk has been expanded north. ...Central Plains and the Black Hills... A mid/upper ridge will remain anchored across the High Plains between the trough over the East and a trough along the Pacific Northwest coast. A plume of rich boundary-layer moisture will persist from the Ozarks into the central High Plains within a modest northwesterly mid-level flow regime. At least isolated elevated convection, driven by low-level warm theta-e advection, should be ongoing at 12Z Sunday across central parts of NE/SD. There's a low probability that this activity could strengthen during the day with a primary threat of isolated severe hail as it gradually sinks southward, or additional isolated surface-based storms may form within the lingering differential heating zone later in the afternoon. Isolated high-based storms may also develop from the Black Hills to eastern CO and spread east-southeast. Localized severe wind/hail will be possible through about dusk. ...Eastern Great Basin to central MT... Isolated to scattered afternoon thunderstorms are expected along the western periphery of the buoyancy plume across the Intermountain West and Rockies. Mid-level southwesterlies will be modestly greater across the eastern Great Basin with peripheral influence of the northward-moving shortwave trough along the Pacific Northwest coast. This should yield moderate storm motions and a threat for sporadic severe gusts with high-based convection. A similar steep lapse rate environment will extend farther north into central MT. However, closer proximity to the mid-level ridge should yield weak deep-layer shear. More pulse-type thunderstorms are expected here, but a threat for dry microbursts capable of strong gusts will be possible. ..Grams.. 08/17/2024 Read more
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sat Aug 17 2024 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE DEEP SOUTH TO THE MID-ATLANTIC STATES... ...SUMMARY... Scattered wind damage will be possible from the Mid-Atlantic States to the Deep South from mid-afternoon to early evening on Sunday. ...Deep South to the Mid-Atlantic States... A persistent, slow-moving mid/upper trough from the eastern Great Lakes to the southern Appalachians should amplify slightly as a mid/upper jetlet digs into the basal portion of the trough. This will result in the belt of enhanced northwesterly to west-southwesterly mid-level flow becoming centered across the Southeast by Sunday afternoon. Occluded surface cyclone should drift east across southern ON into western NY. An arcing cold front will largely extend south across the Mid-Atlantic to Southeast before trailing westward over the Deep South to Lower MS Valley. Hot temperatures from 95-103 F are expected at peak heating along the trailing portion of the front west of the Carolinas. This should yield moderate to large buoyancy amid moderate northwesterly deep-layer shear. Isolated to scattered thunderstorm development is anticipated towards late afternoon along the weakly convergent front. While severe hail is possible, the rather warm thermodynamic profile should largely support a primary threat of scattered damaging winds from strong to severe wind gusts. Confidence is below average in where south-southeast moving clusters should develop, so have maintained a broad level 2-SLGT risk despite some embedded areas likely not having thunder occur. Convective coverage may become widespread across parts of the Lower Mid-Atlantic States where larger-scale ascent with stronger low-level convergence is expected. Although deep-layer shear should be comparatively weaker along with poor mid-level lapse rates, rich boundary-layer moisture and adequate heating should be sufficient for a scattered wind damage threat. Strong to localized severe gusts with slow, eastward-moving multicell clusters will be possible, and the level 2-SLGT risk has been expanded north. ...Central Plains and the Black Hills... A mid/upper ridge will remain anchored across the High Plains between the trough over the East and a trough along the Pacific Northwest coast. A plume of rich boundary-layer moisture will persist from the Ozarks into the central High Plains within a modest northwesterly mid-level flow regime. At least isolated elevated convection, driven by low-level warm theta-e advection, should be ongoing at 12Z Sunday across central parts of NE/SD. There's a low probability that this activity could strengthen during the day with a primary threat of isolated severe hail as it gradually sinks southward, or additional isolated surface-based storms may form within the lingering differential heating zone later in the afternoon. Isolated high-based storms may also develop from the Black Hills to eastern CO and spread east-southeast. Localized severe wind/hail will be possible through about dusk. ...Eastern Great Basin to central MT... Isolated to scattered afternoon thunderstorms are expected along the western periphery of the buoyancy plume across the Intermountain West and Rockies. Mid-level southwesterlies will be modestly greater across the eastern Great Basin with peripheral influence of the northward-moving shortwave trough along the Pacific Northwest coast. This should yield moderate storm motions and a threat for sporadic severe gusts with high-based convection. A similar steep lapse rate environment will extend farther north into central MT. However, closer proximity to the mid-level ridge should yield weak deep-layer shear. More pulse-type thunderstorms are expected here, but a threat for dry microbursts capable of strong gusts will be possible. ..Grams.. 08/17/2024 Read more
SPC Aug 17, 2024 1730 UTC Day 2 Convective Outlook
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sat Aug 17 2024 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE DEEP SOUTH TO THE MID-ATLANTIC STATES... ...SUMMARY... Scattered wind damage will be possible from the Mid-Atlantic States to the Deep South from mid-afternoon to early evening on Sunday. ...Deep South to the Mid-Atlantic States... A persistent, slow-moving mid/upper trough from the eastern Great Lakes to the southern Appalachians should amplify slightly as a mid/upper jetlet digs into the basal portion of the trough. This will result in the belt of enhanced northwesterly to west-southwesterly mid-level flow becoming centered across the Southeast by Sunday afternoon. Occluded surface cyclone should drift east across southern ON into western NY. An arcing cold front will largely extend south across the Mid-Atlantic to Southeast before trailing westward over the Deep South to Lower MS Valley. Hot temperatures from 95-103 F are expected at peak heating along the trailing portion of the front west of the Carolinas. This should yield moderate to large buoyancy amid moderate northwesterly deep-layer shear. Isolated to scattered thunderstorm development is anticipated towards late afternoon along the weakly convergent front. While severe hail is possible, the rather warm thermodynamic profile should largely support a primary threat of scattered damaging winds from strong to severe wind gusts. Confidence is below average in where south-southeast moving clusters should develop, so have maintained a broad level 2-SLGT risk despite some embedded areas likely not having thunder occur. Convective coverage may become widespread across parts of the Lower Mid-Atlantic States where larger-scale ascent with stronger low-level convergence is expected. Although deep-layer shear should be comparatively weaker along with poor mid-level lapse rates, rich boundary-layer moisture and adequate heating should be sufficient for a scattered wind damage threat. Strong to localized severe gusts with slow, eastward-moving multicell clusters will be possible, and the level 2-SLGT risk has been expanded north. ...Central Plains and the Black Hills... A mid/upper ridge will remain anchored across the High Plains between the trough over the East and a trough along the Pacific Northwest coast. A plume of rich boundary-layer moisture will persist from the Ozarks into the central High Plains within a modest northwesterly mid-level flow regime. At least isolated elevated convection, driven by low-level warm theta-e advection, should be ongoing at 12Z Sunday across central parts of NE/SD. There's a low probability that this activity could strengthen during the day with a primary threat of isolated severe hail as it gradually sinks southward, or additional isolated surface-based storms may form within the lingering differential heating zone later in the afternoon. Isolated high-based storms may also develop from the Black Hills to eastern CO and spread east-southeast. Localized severe wind/hail will be possible through about dusk. ...Eastern Great Basin to central MT... Isolated to scattered afternoon thunderstorms are expected along the western periphery of the buoyancy plume across the Intermountain West and Rockies. Mid-level southwesterlies will be modestly greater across the eastern Great Basin with peripheral influence of the northward-moving shortwave trough along the Pacific Northwest coast. This should yield moderate storm motions and a threat for sporadic severe gusts with high-based convection. A similar steep lapse rate environment will extend farther north into central MT. However, closer proximity to the mid-level ridge should yield weak deep-layer shear. More pulse-type thunderstorms are expected here, but a threat for dry microbursts capable of strong gusts will be possible. ..Grams.. 08/17/2024 Read more
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sat Aug 17 2024 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE DEEP SOUTH TO THE MID-ATLANTIC STATES... ...SUMMARY... Scattered wind damage will be possible from the Mid-Atlantic States to the Deep South from mid-afternoon to early evening on Sunday. ...Deep South to the Mid-Atlantic States... A persistent, slow-moving mid/upper trough from the eastern Great Lakes to the southern Appalachians should amplify slightly as a mid/upper jetlet digs into the basal portion of the trough. This will result in the belt of enhanced northwesterly to west-southwesterly mid-level flow becoming centered across the Southeast by Sunday afternoon. Occluded surface cyclone should drift east across southern ON into western NY. An arcing cold front will largely extend south across the Mid-Atlantic to Southeast before trailing westward over the Deep South to Lower MS Valley. Hot temperatures from 95-103 F are expected at peak heating along the trailing portion of the front west of the Carolinas. This should yield moderate to large buoyancy amid moderate northwesterly deep-layer shear. Isolated to scattered thunderstorm development is anticipated towards late afternoon along the weakly convergent front. While severe hail is possible, the rather warm thermodynamic profile should largely support a primary threat of scattered damaging winds from strong to severe wind gusts. Confidence is below average in where south-southeast moving clusters should develop, so have maintained a broad level 2-SLGT risk despite some embedded areas likely not having thunder occur. Convective coverage may become widespread across parts of the Lower Mid-Atlantic States where larger-scale ascent with stronger low-level convergence is expected. Although deep-layer shear should be comparatively weaker along with poor mid-level lapse rates, rich boundary-layer moisture and adequate heating should be sufficient for a scattered wind damage threat. Strong to localized severe gusts with slow, eastward-moving multicell clusters will be possible, and the level 2-SLGT risk has been expanded north. ...Central Plains and the Black Hills... A mid/upper ridge will remain anchored across the High Plains between the trough over the East and a trough along the Pacific Northwest coast. A plume of rich boundary-layer moisture will persist from the Ozarks into the central High Plains within a modest northwesterly mid-level flow regime. At least isolated elevated convection, driven by low-level warm theta-e advection, should be ongoing at 12Z Sunday across central parts of NE/SD. There's a low probability that this activity could strengthen during the day with a primary threat of isolated severe hail as it gradually sinks southward, or additional isolated surface-based storms may form within the lingering differential heating zone later in the afternoon. Isolated high-based storms may also develop from the Black Hills to eastern CO and spread east-southeast. Localized severe wind/hail will be possible through about dusk. ...Eastern Great Basin to central MT... Isolated to scattered afternoon thunderstorms are expected along the western periphery of the buoyancy plume across the Intermountain West and Rockies. Mid-level southwesterlies will be modestly greater across the eastern Great Basin with peripheral influence of the northward-moving shortwave trough along the Pacific Northwest coast. This should yield moderate storm motions and a threat for sporadic severe gusts with high-based convection. A similar steep lapse rate environment will extend farther north into central MT. However, closer proximity to the mid-level ridge should yield weak deep-layer shear. More pulse-type thunderstorms are expected here, but a threat for dry microbursts capable of strong gusts will be possible. ..Grams.. 08/17/2024 Read more
SPC Day 1 Fire Weather Outlook
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1150 AM CDT Sat Aug 17 2024 Valid 171700Z - 181200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHEAST OREGON... ...CRITICAL FIRE WEATHER AREA FOR SOUTHWEST NEVADA... No changes are needed to the ongoing forecast. Thunderstorms are expected to develop this afternoon across portions of the Cascades. Mid-level flow is strong enough to support fast storm motions, but with increasing precipitable water and overall thunderstorm coverage should limit dry thunderstorm potential to early on in the thunderstorm life cycle. As such, have left the isolated dry thunderstorm area as is. ..Marsh.. 08/17/2024 .PREV DISCUSSION... /ISSUED 0152 AM CDT Sat Aug 17 2024/ ...Synopsis... A mid-level trough will impinge on the West Coast as upper ridging amplifies over the Rockies into the Plains today. Surface cyclone development is likely to the lee of the Cascades by afternoon, promoting ample buoyancy, lift, and shear for thunderstorms, some of which may be strong. Otherwise, strong downslope and isallobaric flow across the western Great Basin ahead of the upper trough/surface low will promote widespread dry and breezy conditions capable of supporting wildfire spread. ...Along and to the lee of the Cascades - Thunderstorms... By late afternoon, multiple strong thunderstorms should develop amid strong flow aloft. Some of the storms may be high-based, with a couple of dry strikes possible. Of greater concern is the potential for erratic and strong to possibly severe gusts, which may exacerbate ongoing fire concerns, as well as with ignitions from strikes accompanying the storms. Given receptive fuels, isolated dry thunderstorm highlights have been maintained. ...Harney Basin and western Great Basin - Dry/Windy Conditions... By afternoon peak heating, RH is expected to drop into the 15-20 percent range as the boundary layer mixes. When also considering the contribution of isallobaric flow, winds may sustain above 20 mph, particularly over portions of the Harney Basin and in southwestern Nevada, where Critical highlights have been maintained. Otherwise, Elevated highlights remain over a broader area where dry and breezy conditions are expected to overlap with dry fuel beds. ...Please see www.spc.noaa.gov/fire for graphic product... Read more
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1150 AM CDT Sat Aug 17 2024 Valid 171700Z - 181200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHEAST OREGON... ...CRITICAL FIRE WEATHER AREA FOR SOUTHWEST NEVADA... No changes are needed to the ongoing forecast. Thunderstorms are expected to develop this afternoon across portions of the Cascades. Mid-level flow is strong enough to support fast storm motions, but with increasing precipitable water and overall thunderstorm coverage should limit dry thunderstorm potential to early on in the thunderstorm life cycle. As such, have left the isolated dry thunderstorm area as is. ..Marsh.. 08/17/2024 .PREV DISCUSSION... /ISSUED 0152 AM CDT Sat Aug 17 2024/ ...Synopsis... A mid-level trough will impinge on the West Coast as upper ridging amplifies over the Rockies into the Plains today. Surface cyclone development is likely to the lee of the Cascades by afternoon, promoting ample buoyancy, lift, and shear for thunderstorms, some of which may be strong. Otherwise, strong downslope and isallobaric flow across the western Great Basin ahead of the upper trough/surface low will promote widespread dry and breezy conditions capable of supporting wildfire spread. ...Along and to the lee of the Cascades - Thunderstorms... By late afternoon, multiple strong thunderstorms should develop amid strong flow aloft. Some of the storms may be high-based, with a couple of dry strikes possible. Of greater concern is the potential for erratic and strong to possibly severe gusts, which may exacerbate ongoing fire concerns, as well as with ignitions from strikes accompanying the storms. Given receptive fuels, isolated dry thunderstorm highlights have been maintained. ...Harney Basin and western Great Basin - Dry/Windy Conditions... By afternoon peak heating, RH is expected to drop into the 15-20 percent range as the boundary layer mixes. When also considering the contribution of isallobaric flow, winds may sustain above 20 mph, particularly over portions of the Harney Basin and in southwestern Nevada, where Critical highlights have been maintained. Otherwise, Elevated highlights remain over a broader area where dry and breezy conditions are expected to overlap with dry fuel beds. ...Please see www.spc.noaa.gov/fire for graphic product... Read more
SPC Day 1 Fire Weather Outlook
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1150 AM CDT Sat Aug 17 2024 Valid 171700Z - 181200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHEAST OREGON... ...CRITICAL FIRE WEATHER AREA FOR SOUTHWEST NEVADA... No changes are needed to the ongoing forecast. Thunderstorms are expected to develop this afternoon across portions of the Cascades. Mid-level flow is strong enough to support fast storm motions, but with increasing precipitable water and overall thunderstorm coverage should limit dry thunderstorm potential to early on in the thunderstorm life cycle. As such, have left the isolated dry thunderstorm area as is. ..Marsh.. 08/17/2024 .PREV DISCUSSION... /ISSUED 0152 AM CDT Sat Aug 17 2024/ ...Synopsis... A mid-level trough will impinge on the West Coast as upper ridging amplifies over the Rockies into the Plains today. Surface cyclone development is likely to the lee of the Cascades by afternoon, promoting ample buoyancy, lift, and shear for thunderstorms, some of which may be strong. Otherwise, strong downslope and isallobaric flow across the western Great Basin ahead of the upper trough/surface low will promote widespread dry and breezy conditions capable of supporting wildfire spread. ...Along and to the lee of the Cascades - Thunderstorms... By late afternoon, multiple strong thunderstorms should develop amid strong flow aloft. Some of the storms may be high-based, with a couple of dry strikes possible. Of greater concern is the potential for erratic and strong to possibly severe gusts, which may exacerbate ongoing fire concerns, as well as with ignitions from strikes accompanying the storms. Given receptive fuels, isolated dry thunderstorm highlights have been maintained. ...Harney Basin and western Great Basin - Dry/Windy Conditions... By afternoon peak heating, RH is expected to drop into the 15-20 percent range as the boundary layer mixes. When also considering the contribution of isallobaric flow, winds may sustain above 20 mph, particularly over portions of the Harney Basin and in southwestern Nevada, where Critical highlights have been maintained. Otherwise, Elevated highlights remain over a broader area where dry and breezy conditions are expected to overlap with dry fuel beds. ...Please see www.spc.noaa.gov/fire for graphic product... Read more
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1150 AM CDT Sat Aug 17 2024 Valid 171700Z - 181200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHEAST OREGON... ...CRITICAL FIRE WEATHER AREA FOR SOUTHWEST NEVADA... No changes are needed to the ongoing forecast. Thunderstorms are expected to develop this afternoon across portions of the Cascades. Mid-level flow is strong enough to support fast storm motions, but with increasing precipitable water and overall thunderstorm coverage should limit dry thunderstorm potential to early on in the thunderstorm life cycle. As such, have left the isolated dry thunderstorm area as is. ..Marsh.. 08/17/2024 .PREV DISCUSSION... /ISSUED 0152 AM CDT Sat Aug 17 2024/ ...Synopsis... A mid-level trough will impinge on the West Coast as upper ridging amplifies over the Rockies into the Plains today. Surface cyclone development is likely to the lee of the Cascades by afternoon, promoting ample buoyancy, lift, and shear for thunderstorms, some of which may be strong. Otherwise, strong downslope and isallobaric flow across the western Great Basin ahead of the upper trough/surface low will promote widespread dry and breezy conditions capable of supporting wildfire spread. ...Along and to the lee of the Cascades - Thunderstorms... By late afternoon, multiple strong thunderstorms should develop amid strong flow aloft. Some of the storms may be high-based, with a couple of dry strikes possible. Of greater concern is the potential for erratic and strong to possibly severe gusts, which may exacerbate ongoing fire concerns, as well as with ignitions from strikes accompanying the storms. Given receptive fuels, isolated dry thunderstorm highlights have been maintained. ...Harney Basin and western Great Basin - Dry/Windy Conditions... By afternoon peak heating, RH is expected to drop into the 15-20 percent range as the boundary layer mixes. When also considering the contribution of isallobaric flow, winds may sustain above 20 mph, particularly over portions of the Harney Basin and in southwestern Nevada, where Critical highlights have been maintained. Otherwise, Elevated highlights remain over a broader area where dry and breezy conditions are expected to overlap with dry fuel beds. ...Please see www.spc.noaa.gov/fire for graphic product... Read more
SPC Aug 17, 2024 1630 UTC Day 1 Convective Outlook
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CDT Sat Aug 17 2024 Valid 171630Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE CASCADES OF OREGON AND WASHINGTON...CENTRAL KENTUCKY INTO SOUTHERN OHIO...AND UTAH.... ...SUMMARY... Scattered severe thunderstorms are possible today in vicinity of the Cascades of Oregon and Washington, Kentucky, and Utah. Wind and hail are the primary threats. ...CA/OR/WA... Morning water vapor loop shows a strong and fast-moving shortwave trough approaching the coast of northern CA. This feature will rotate inland, affecting the Cascades region this afternoon and evening. Steep mid level lapse rates and pockets of MLCAPE of 500-1000 J/kg will aid in the development of scattered thunderstorms by early afternoon over the mountains and coastal ranges of northern CA, building quickly northward into southern/central OR. Winds aloft will be strenghtening during this period, allowing a few supercell storm structures to likely develop. These storms may pose a threat of large hail and locally damaging wind gusts through the afternoon as they track northward into WA. Other high-based storms capable of gusty/damaging winds may affect parts of the Columbia Basin of northern OR/central WA as well. ...UT... A compact shortwave trough over central NV will continue to rotate around the Four-Corners upper ridge into UT today. Considerable coverage of afternoon thunderstorms will likely accompany this system. Winds aloft will be relatively strong, favoring faster-moving organized multicell or occasional supercell structures capable of damaging winds and hail. One forecast uncertainty is the extent of morning cloudiness and its impact on afternoon destabilization. Regardless, at least isolated severe storms are expected, with some threat spreading into southwest WY by evening. ...Eastern US... A broad upper trough will affect much of the eastern US today, with clusters of thunderstorms from NY/PA across the Appalachians into the Mid South. Any of these clusters may occasionally pose a risk of locally gusty/damaging wind gusts or hail. However, perhaps a more focused area of concern will extend from northern TN into southern OH. The axis of the mid level speed max (~40 knots) will spread across this area during the afternoon. CAM guidance has been consistent on suggesting a higher confidence in a few intense cells in this region. ..Hart/Thornton.. 08/17/2024 Read more
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CDT Sat Aug 17 2024 Valid 171630Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE CASCADES OF OREGON AND WASHINGTON...CENTRAL KENTUCKY INTO SOUTHERN OHIO...AND UTAH.... ...SUMMARY... Scattered severe thunderstorms are possible today in vicinity of the Cascades of Oregon and Washington, Kentucky, and Utah. Wind and hail are the primary threats. ...CA/OR/WA... Morning water vapor loop shows a strong and fast-moving shortwave trough approaching the coast of northern CA. This feature will rotate inland, affecting the Cascades region this afternoon and evening. Steep mid level lapse rates and pockets of MLCAPE of 500-1000 J/kg will aid in the development of scattered thunderstorms by early afternoon over the mountains and coastal ranges of northern CA, building quickly northward into southern/central OR. Winds aloft will be strenghtening during this period, allowing a few supercell storm structures to likely develop. These storms may pose a threat of large hail and locally damaging wind gusts through the afternoon as they track northward into WA. Other high-based storms capable of gusty/damaging winds may affect parts of the Columbia Basin of northern OR/central WA as well. ...UT... A compact shortwave trough over central NV will continue to rotate around the Four-Corners upper ridge into UT today. Considerable coverage of afternoon thunderstorms will likely accompany this system. Winds aloft will be relatively strong, favoring faster-moving organized multicell or occasional supercell structures capable of damaging winds and hail. One forecast uncertainty is the extent of morning cloudiness and its impact on afternoon destabilization. Regardless, at least isolated severe storms are expected, with some threat spreading into southwest WY by evening. ...Eastern US... A broad upper trough will affect much of the eastern US today, with clusters of thunderstorms from NY/PA across the Appalachians into the Mid South. Any of these clusters may occasionally pose a risk of locally gusty/damaging wind gusts or hail. However, perhaps a more focused area of concern will extend from northern TN into southern OH. The axis of the mid level speed max (~40 knots) will spread across this area during the afternoon. CAM guidance has been consistent on suggesting a higher confidence in a few intense cells in this region. ..Hart/Thornton.. 08/17/2024 Read more
SPC Aug 17, 2024 1630 UTC Day 1 Convective Outlook
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CDT Sat Aug 17 2024 Valid 171630Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE CASCADES OF OREGON AND WASHINGTON...CENTRAL KENTUCKY INTO SOUTHERN OHIO...AND UTAH.... ...SUMMARY... Scattered severe thunderstorms are possible today in vicinity of the Cascades of Oregon and Washington, Kentucky, and Utah. Wind and hail are the primary threats. ...CA/OR/WA... Morning water vapor loop shows a strong and fast-moving shortwave trough approaching the coast of northern CA. This feature will rotate inland, affecting the Cascades region this afternoon and evening. Steep mid level lapse rates and pockets of MLCAPE of 500-1000 J/kg will aid in the development of scattered thunderstorms by early afternoon over the mountains and coastal ranges of northern CA, building quickly northward into southern/central OR. Winds aloft will be strenghtening during this period, allowing a few supercell storm structures to likely develop. These storms may pose a threat of large hail and locally damaging wind gusts through the afternoon as they track northward into WA. Other high-based storms capable of gusty/damaging winds may affect parts of the Columbia Basin of northern OR/central WA as well. ...UT... A compact shortwave trough over central NV will continue to rotate around the Four-Corners upper ridge into UT today. Considerable coverage of afternoon thunderstorms will likely accompany this system. Winds aloft will be relatively strong, favoring faster-moving organized multicell or occasional supercell structures capable of damaging winds and hail. One forecast uncertainty is the extent of morning cloudiness and its impact on afternoon destabilization. Regardless, at least isolated severe storms are expected, with some threat spreading into southwest WY by evening. ...Eastern US... A broad upper trough will affect much of the eastern US today, with clusters of thunderstorms from NY/PA across the Appalachians into the Mid South. Any of these clusters may occasionally pose a risk of locally gusty/damaging wind gusts or hail. However, perhaps a more focused area of concern will extend from northern TN into southern OH. The axis of the mid level speed max (~40 knots) will spread across this area during the afternoon. CAM guidance has been consistent on suggesting a higher confidence in a few intense cells in this region. ..Hart/Thornton.. 08/17/2024 Read more
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CDT Sat Aug 17 2024 Valid 171630Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE CASCADES OF OREGON AND WASHINGTON...CENTRAL KENTUCKY INTO SOUTHERN OHIO...AND UTAH.... ...SUMMARY... Scattered severe thunderstorms are possible today in vicinity of the Cascades of Oregon and Washington, Kentucky, and Utah. Wind and hail are the primary threats. ...CA/OR/WA... Morning water vapor loop shows a strong and fast-moving shortwave trough approaching the coast of northern CA. This feature will rotate inland, affecting the Cascades region this afternoon and evening. Steep mid level lapse rates and pockets of MLCAPE of 500-1000 J/kg will aid in the development of scattered thunderstorms by early afternoon over the mountains and coastal ranges of northern CA, building quickly northward into southern/central OR. Winds aloft will be strenghtening during this period, allowing a few supercell storm structures to likely develop. These storms may pose a threat of large hail and locally damaging wind gusts through the afternoon as they track northward into WA. Other high-based storms capable of gusty/damaging winds may affect parts of the Columbia Basin of northern OR/central WA as well. ...UT... A compact shortwave trough over central NV will continue to rotate around the Four-Corners upper ridge into UT today. Considerable coverage of afternoon thunderstorms will likely accompany this system. Winds aloft will be relatively strong, favoring faster-moving organized multicell or occasional supercell structures capable of damaging winds and hail. One forecast uncertainty is the extent of morning cloudiness and its impact on afternoon destabilization. Regardless, at least isolated severe storms are expected, with some threat spreading into southwest WY by evening. ...Eastern US... A broad upper trough will affect much of the eastern US today, with clusters of thunderstorms from NY/PA across the Appalachians into the Mid South. Any of these clusters may occasionally pose a risk of locally gusty/damaging wind gusts or hail. However, perhaps a more focused area of concern will extend from northern TN into southern OH. The axis of the mid level speed max (~40 knots) will spread across this area during the afternoon. CAM guidance has been consistent on suggesting a higher confidence in a few intense cells in this region. ..Hart/Thornton.. 08/17/2024 Read more
SPC - No MDs are in effect as of Sat Aug 17 14:04:01 UTC 2024
No Mesoscale Discussions are in effect as of Sat Aug 17 14:04:01 UTC 2024.
SPC Aug 17, 2024 1300 UTC Day 1 Convective Outlook
SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Sat Aug 17 2024 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR CENTRAL KENTUCKY INTO SOUTHERN OHIO...UTAH...AND PARTS OF THE CASCADES OF OREGON AND WASHINGTON... ...SUMMARY... Scattered severe thunderstorms are possible in parts of Kentucky and the Ohio Valley mainly this afternoon into the early evening. Scattered severe thunderstorms are also forecast for Utah and in the vicinity of the Cascades of Oregon and Washington. Wind and hail are the primary threats. ...Lower Great Lakes into the central/southern Appalachians and OH Valley... A mid-level low and associated trough will slowly move east today and reach the Upper OH Valley/Appalachians tonight as a mid-level anticyclone remains centered over northeast NM. High-level diffluent flow will be noted across the OH Valley into the Mid South and be favorable for scattered thunderstorms developing across much of this region coincident with strong heating. A front will gradually shift east across the OH Valley with this boundary becoming more diffuse in part related to convective outflow across the Mid South/Ozarks. Stronger mid-level flow aiding in storm organization will primarily extend from the Great Smoky Mtns northward into KY/OH/WV. Organized multicells and transient supercells are possible with scattered coverage of severe wind/hail possible with these storms. Observational trends of an MCV over Middle TN moving eastward into the southern Appalachians and the 00z MPAS-NSSL model run data, lend the possibility for a mesoscale corridor of higher thunderstorm coverage and greater damaging-wind potential for the western Carolinas and perhaps into central portions of AL. Limited confidence in this scenario precludes higher severe probabilities at this time. ...Lower MS Valley into north TX... Morning thunderstorms over the OK/AR border associated with low-level WAA may continue into the midday with incipient outflow progressively shunting additional storms/new development farther west and south across eastern OK. Model guidance indicates at least isolated storms potentially developing within an east-west corridor from MS westward into north/northwest TX later today. Forecast soundings indicate severe microbursts will be possible with the more intense cores. Have adjusted low-severe probabilities to trend farther west/southwest based on this forecast scenario. ...Utah Region... Water-vapor imagery this morning shows a northward-moving shortwave trough over southern NV and extrapolation has this feature moving into northern UT by mid afternoon. Scattered to numerous thunderstorms are forecast to begin developing by late morning and spreading north-northeast within a strongly sheared environment. Increasing cloud cover and some limit on the quality of lapse rates will temper overall buoyancy. However, some organization into small clusters yielding severe gusts will be the primary threat with the stronger storms. ...Western OR/Southwest WA... Strong 500mb speed max will round the base of the offshore trough and translate across northern CA into eastern OR by early evening. Left exit region of this feature will aid UVV near the higher terrain and cooling/moistening mid-levels will contribute to modest buoyancy along the cyclonic side of the speed max. Forecast soundings exhibit strongly sheared profiles and isolated supercells are expected to develop, then spread north-northeast as a short-wave trough ejects into southern WA. Hail/wind are possible with these storms. ..Smith/Mosier.. 08/17/2024 Read more
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Sat Aug 17 2024 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR CENTRAL KENTUCKY INTO SOUTHERN OHIO...UTAH...AND PARTS OF THE CASCADES OF OREGON AND WASHINGTON... ...SUMMARY... Scattered severe thunderstorms are possible in parts of Kentucky and the Ohio Valley mainly this afternoon into the early evening. Scattered severe thunderstorms are also forecast for Utah and in the vicinity of the Cascades of Oregon and Washington. Wind and hail are the primary threats. ...Lower Great Lakes into the central/southern Appalachians and OH Valley... A mid-level low and associated trough will slowly move east today and reach the Upper OH Valley/Appalachians tonight as a mid-level anticyclone remains centered over northeast NM. High-level diffluent flow will be noted across the OH Valley into the Mid South and be favorable for scattered thunderstorms developing across much of this region coincident with strong heating. A front will gradually shift east across the OH Valley with this boundary becoming more diffuse in part related to convective outflow across the Mid South/Ozarks. Stronger mid-level flow aiding in storm organization will primarily extend from the Great Smoky Mtns northward into KY/OH/WV. Organized multicells and transient supercells are possible with scattered coverage of severe wind/hail possible with these storms. Observational trends of an MCV over Middle TN moving eastward into the southern Appalachians and the 00z MPAS-NSSL model run data, lend the possibility for a mesoscale corridor of higher thunderstorm coverage and greater damaging-wind potential for the western Carolinas and perhaps into central portions of AL. Limited confidence in this scenario precludes higher severe probabilities at this time. ...Lower MS Valley into north TX... Morning thunderstorms over the OK/AR border associated with low-level WAA may continue into the midday with incipient outflow progressively shunting additional storms/new development farther west and south across eastern OK. Model guidance indicates at least isolated storms potentially developing within an east-west corridor from MS westward into north/northwest TX later today. Forecast soundings indicate severe microbursts will be possible with the more intense cores. Have adjusted low-severe probabilities to trend farther west/southwest based on this forecast scenario. ...Utah Region... Water-vapor imagery this morning shows a northward-moving shortwave trough over southern NV and extrapolation has this feature moving into northern UT by mid afternoon. Scattered to numerous thunderstorms are forecast to begin developing by late morning and spreading north-northeast within a strongly sheared environment. Increasing cloud cover and some limit on the quality of lapse rates will temper overall buoyancy. However, some organization into small clusters yielding severe gusts will be the primary threat with the stronger storms. ...Western OR/Southwest WA... Strong 500mb speed max will round the base of the offshore trough and translate across northern CA into eastern OR by early evening. Left exit region of this feature will aid UVV near the higher terrain and cooling/moistening mid-levels will contribute to modest buoyancy along the cyclonic side of the speed max. Forecast soundings exhibit strongly sheared profiles and isolated supercells are expected to develop, then spread north-northeast as a short-wave trough ejects into southern WA. Hail/wind are possible with these storms. ..Smith/Mosier.. 08/17/2024 Read more
SPC Aug 17, 2024 Day 4-8 Severe Weather Outlook
Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CDT Sat Aug 17 2024 Valid 201200Z - 251200Z ...DISCUSSION... ...Tuesday/Day 4 to Thursday/Day 6... A shortwave ridge over the eastern part of the northern Plains is forecast to deamplify on Tuesday. Further west, the large-scale upper-level ridge is forecast to move eastward across the northern Plains on Tuesday and into the upper Mississippi Valley from Wednesday into Thursday. This feature will move away from a moist axis in the northern Plains, where moderate instability is forecast each afternoon. Thunderstorm development, some with potential for isolated large hail and severe wind gusts, will be possible each day. The greatest severe threat during the mid-week is expected on Wednesday in the Dakotas, where southwest mid-level flow and strong instability is forecast in the wake of the upper-level ridge. ...Friday/Day 7 and Saturday/Day 8... On Friday, some model solutions deepen an upper-level trough over the Intermountain West. In response, the north-central U.S upper-level ridge would move eastward toward the western Great Lakes. Isolated thunderstorms, possibly associated with a severe threat, would be possible within a moist airmass located further to the west from Nebraska into the Dakotas. However, some solutions are slow to move the upper-level trough into the western U.S. This would keep the upper-level ridge further west, negatively impacting the severe potential across the northern Plains. Under this scenario, storm coverage would be more isolated and the severe threat would not be as great. Read more
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CDT Sat Aug 17 2024 Valid 201200Z - 251200Z ...DISCUSSION... ...Tuesday/Day 4 to Thursday/Day 6... A shortwave ridge over the eastern part of the northern Plains is forecast to deamplify on Tuesday. Further west, the large-scale upper-level ridge is forecast to move eastward across the northern Plains on Tuesday and into the upper Mississippi Valley from Wednesday into Thursday. This feature will move away from a moist axis in the northern Plains, where moderate instability is forecast each afternoon. Thunderstorm development, some with potential for isolated large hail and severe wind gusts, will be possible each day. The greatest severe threat during the mid-week is expected on Wednesday in the Dakotas, where southwest mid-level flow and strong instability is forecast in the wake of the upper-level ridge. ...Friday/Day 7 and Saturday/Day 8... On Friday, some model solutions deepen an upper-level trough over the Intermountain West. In response, the north-central U.S upper-level ridge would move eastward toward the western Great Lakes. Isolated thunderstorms, possibly associated with a severe threat, would be possible within a moist airmass located further to the west from Nebraska into the Dakotas. However, some solutions are slow to move the upper-level trough into the western U.S. This would keep the upper-level ridge further west, negatively impacting the severe potential across the northern Plains. Under this scenario, storm coverage would be more isolated and the severe threat would not be as great. Read more
SPC Aug 17, 2024 0730 UTC Day 3 Severe Thunderstorm Outlook
SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Sat Aug 17 2024 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS FROM THE MID-ATLANTIC INTO NORTH CAROLINA...AND ACROSS PARTS OF THE CENTRAL AND NORTHERN HIGH PLAINS... ...SUMMARY... Thunderstorms, associated with a marginal severe threat, will be possible on Monday in parts of the Mid-Atlantic, North Carolina, and from the central to the northern High Plains. ...Mid-Atlantic/North Carolina... An upper-level trough will move slowly eastward across the southern and central Appalachians on Monday, as a cold front advances southeastward toward the middle Atlantic Coast. Surface dewpoints across most of the Mid-Atlantic into North Carolina are forecast to be in the 60s F, with 70+ surface dewpoints confined to the immediate Atlantic coast. As surface temperatures warm, a pocket of instability will likely develop near and ahead of the front, and in the post-frontal airmass. Scattered thunderstorms are expected to form within these areas as surface temperatures warm during the day. Although low-level lapse rates will become steep in many areas by afternoon, deep-layer shear is forecast to remain relatively weak. The instability could still be strong enough for a marginal severe threat. Isolated strong to severe wind gusts could occur near and around peak heating. ...Central to Northern High Plains... An upper-level ridge is forecast to move across the Central High Plains and northern Plains on Monday. An axis of instability will likely develop during the day to the west of the ridge, from eastern Colorado northward into eastern Montana and western North Dakota. Although large-scale ascent will be weak along this corridor, thunderstorms are expected to form in some areas due to topographical forcing in the central and northern Rockies. More isolated storms will be possible in the lower elevations of the central and northern High Plains. Forecast soundings across the central and northern High Plains have steep low to mid-level lapse rates and sufficient deep-layer shear for a marginal severe threat. Relatively large surface temperature-dewpoint spreads could enhance downdrafts associated with high-based storms. Hail could also accompany the stronger cells, especially further west near the higher terrain. ...Ark-La-Tex... North-northwesterly mid-level flow will be in place across the Ark-La-Tex on Monday. At the surface, a quasi-stationary front is forecast from northeast Texas into Louisiana, where surface dewpoints should be in the lower 70s F. As surface temperatures warm during the day, low-level lapse rates will become steep. This combined with moderate deep-layer shear may support an isolated severe threat. Although there is some uncertainty concerning convective coverage, the forecast environment should be enough for a few marginally severe storms. ..Broyles.. 08/17/2024 Read more
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Sat Aug 17 2024 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS FROM THE MID-ATLANTIC INTO NORTH CAROLINA...AND ACROSS PARTS OF THE CENTRAL AND NORTHERN HIGH PLAINS... ...SUMMARY... Thunderstorms, associated with a marginal severe threat, will be possible on Monday in parts of the Mid-Atlantic, North Carolina, and from the central to the northern High Plains. ...Mid-Atlantic/North Carolina... An upper-level trough will move slowly eastward across the southern and central Appalachians on Monday, as a cold front advances southeastward toward the middle Atlantic Coast. Surface dewpoints across most of the Mid-Atlantic into North Carolina are forecast to be in the 60s F, with 70+ surface dewpoints confined to the immediate Atlantic coast. As surface temperatures warm, a pocket of instability will likely develop near and ahead of the front, and in the post-frontal airmass. Scattered thunderstorms are expected to form within these areas as surface temperatures warm during the day. Although low-level lapse rates will become steep in many areas by afternoon, deep-layer shear is forecast to remain relatively weak. The instability could still be strong enough for a marginal severe threat. Isolated strong to severe wind gusts could occur near and around peak heating. ...Central to Northern High Plains... An upper-level ridge is forecast to move across the Central High Plains and northern Plains on Monday. An axis of instability will likely develop during the day to the west of the ridge, from eastern Colorado northward into eastern Montana and western North Dakota. Although large-scale ascent will be weak along this corridor, thunderstorms are expected to form in some areas due to topographical forcing in the central and northern Rockies. More isolated storms will be possible in the lower elevations of the central and northern High Plains. Forecast soundings across the central and northern High Plains have steep low to mid-level lapse rates and sufficient deep-layer shear for a marginal severe threat. Relatively large surface temperature-dewpoint spreads could enhance downdrafts associated with high-based storms. Hail could also accompany the stronger cells, especially further west near the higher terrain. ...Ark-La-Tex... North-northwesterly mid-level flow will be in place across the Ark-La-Tex on Monday. At the surface, a quasi-stationary front is forecast from northeast Texas into Louisiana, where surface dewpoints should be in the lower 70s F. As surface temperatures warm during the day, low-level lapse rates will become steep. This combined with moderate deep-layer shear may support an isolated severe threat. Although there is some uncertainty concerning convective coverage, the forecast environment should be enough for a few marginally severe storms. ..Broyles.. 08/17/2024 Read more
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