SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1024 AM CDT Tue Aug 13 2024 Valid 131700Z - 141200Z The previous forecast remains on track with some adjustments made to the isolated dry-thunderstorm risk area. This was done primarily to account for the cessation of thunderstorm potential across parts of northeast OR/far southwest WA as the first round of convection exits the region and is followed by areas of wetting rainfall (per MRMS estimates). A second round of isolated dry thunderstorms is still anticipated this afternoon across parts of eastern OR into west/southwest ID. See the previous discussion for additional details. ..Moore.. 08/13/2024 .PREV DISCUSSION... /ISSUED 0146 AM CDT Tue Aug 13 2024/ ...Synopsis... A mid-level shortwave trough and associated vorticity maximum will move northeastward from California into eastern Oregon and Washington. In response to the approaching trough, southerly low-level flow will transport modified monsoonal moisture northward into portions of eastern Oregon and into Idaho, where modest PWAT values of 0.6-0.8 will support the occurrence of dry thunderstorms. Some locally enhanced fire-weather conditions are possible across portions of the Great Basin, particularly in northeastern Nevada. However, in the absence of any large-scale pressure gradients, any stronger winds will be diurnally/terrain-driven. ...Dry Thunderstorms... Two rounds of dry thunderstorms are possible across portions of eastern Oregon and into Idaho, where some dry thunder will be ongoing at the start of the forecast period, and another round should develop around 21Z. Current forecast guidance places more confidence in the later-period thunder, rather than the early-period thunder. However, with modest PWAT values and storm motions of about 25-30 kts, wetting rainfall will be limited over fuels that are receptive to new ignitions. ...Dry/Windy... Some locally elevated fire-weather conditions are possible across northeastern Nevada. While fuels guidance suggests some receptiveness to new ignitions, and relative humidity values will fall to 15-20%, sustained winds reaching elevated criteria will be localized to terrain features. This will preclude any highlight areas at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 0854 AM CDT Tue Aug 13 2024 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE EASTERN GREAT BASIN/NORTHERN INTERMOUNTAIN REGION INTO THE NORTHERN AND CENTRAL HIGH PLAINS...CENTRAL GREAT PLAINS...AS WELL AS SOUTH CAROLINA... CORRECTED FOR ERROR IN TEXT ...SUMMARY... Isolated severe thunderstorms are possible this afternoon and evening across parts of the eastern Great Basin/northern Intermountain region into the northern/central High Plains and central Great Plains, as well as South Carolina. ...The Intermountain Region to the central and northern High Plains... Several weak disturbances/vorticity maxima are forecast to move through the broader/weakly cyclonic flow field that will persist across the West today. A residual plume of seasonably high moisture resides from the Four Corners northward into the northern High Plains. The most notable mid-level shortwave will move from the OR/NV vicinity this morning northeastward into MT this afternoon/evening. Heating will contribute to weak to moderate instability across this broad region from the Interior West to the High Plains. Scattered to numerous thunderstorms are forecast to develop by late this afternoon into the early evening. A locally greater severe risk may evolve from eastern ID into northern UT where forecast soundings show shear profiles supporting a mixed mode of supercells/multicells. However, some uncertainty remains due to ongoing early morning convection and related airmass recovery. Nonetheless, an isolated risk for hail/wind will likely encompass the UT/ID/WY/MT corridor. Farther east and northeast, an isolated threat for hail/wind will potentially accompany the stronger late-day storms with some of this activity lingering into the evening across eastern CO in the form of a thunderstorm cluster. ...Central Plains/lower MO Valley... As a 40-plus kt south-southwesterly low-level jet develops across the central Plains during the evening, elevated storm development is expected north of a west-to-east surface front forecast to reside over central Kansas. With moderate CAPE expected atop the cool/stable boundary layer north of the front, a few stronger storms are expected to evolve, potentially capable of producing hail at or exceeding severe levels. Strong/gusty outflow winds will also be possible, particularly with storms nearer the frontal zone. ...South Carolina... Surface analysis this morning depicts a remnant weak frontal zone draped from southern GA into the Carolinas. A very moist airmass sampled by the 12 UTC Charleston raob (16.7 g/kg lowest 100-mb mean mixing ratio) will diurnally destabilize today. Weak convergence via the frontal zone will aid in widely scattered storms developing by early to mid afternoon due to a negligible cap. A mid to upper-level disturbance moving southeast into the southern Appalachians this morning will move to the Carolina coastal plain later today. Moderate west-northwesterlies (around 30 kt at 500 mb) may aid in some multicellular organization. Isolated gusts 50-60 mph capable of wind damage will be the primary concern with the stronger storms. ..Smith/Jewell.. 08/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 0854 AM CDT Tue Aug 13 2024 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE EASTERN GREAT BASIN/NORTHERN INTERMOUNTAIN REGION INTO THE NORTHERN AND CENTRAL HIGH PLAINS...CENTRAL GREAT PLAINS...AS WELL AS SOUTH CAROLINA... CORRECTED FOR ERROR IN TEXT ...SUMMARY... Isolated severe thunderstorms are possible this afternoon and evening across parts of the eastern Great Basin/northern Intermountain region into the northern/central High Plains and central Great Plains, as well as South Carolina. ...The Intermountain Region to the central and northern High Plains... Several weak disturbances/vorticity maxima are forecast to move through the broader/weakly cyclonic flow field that will persist across the West today. A residual plume of seasonably high moisture resides from the Four Corners northward into the northern High Plains. The most notable mid-level shortwave will move from the OR/NV vicinity this morning northeastward into MT this afternoon/evening. Heating will contribute to weak to moderate instability across this broad region from the Interior West to the High Plains. Scattered to numerous thunderstorms are forecast to develop by late this afternoon into the early evening. A locally greater severe risk may evolve from eastern ID into northern UT where forecast soundings show shear profiles supporting a mixed mode of supercells/multicells. However, some uncertainty remains due to ongoing early morning convection and related airmass recovery. Nonetheless, an isolated risk for hail/wind will likely encompass the UT/ID/WY/MT corridor. Farther east and northeast, an isolated threat for hail/wind will potentially accompany the stronger late-day storms with some of this activity lingering into the evening across eastern CO in the form of a thunderstorm cluster. ...Central Plains/lower MO Valley... As a 40-plus kt south-southwesterly low-level jet develops across the central Plains during the evening, elevated storm development is expected north of a west-to-east surface front forecast to reside over central Kansas. With moderate CAPE expected atop the cool/stable boundary layer north of the front, a few stronger storms are expected to evolve, potentially capable of producing hail at or exceeding severe levels. Strong/gusty outflow winds will also be possible, particularly with storms nearer the frontal zone. ...South Carolina... Surface analysis this morning depicts a remnant weak frontal zone draped from southern GA into the Carolinas. A very moist airmass sampled by the 12 UTC Charleston raob (16.7 g/kg lowest 100-mb mean mixing ratio) will diurnally destabilize today. Weak convergence via the frontal zone will aid in widely scattered storms developing by early to mid afternoon due to a negligible cap. A mid to upper-level disturbance moving southeast into the southern Appalachians this morning will move to the Carolina coastal plain later today. Moderate west-northwesterlies (around 30 kt at 500 mb) may aid in some multicellular organization. Isolated gusts 50-60 mph capable of wind damage will be the primary concern with the stronger storms. ..Smith/Jewell.. 08/13/2024 Read more

No Mesoscale Discussions are in effect as of Tue Aug 13 13:59:02 UTC 2024.

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook RESENT 1 NWS Storm Prediction Center Norman OK 0315 AM CDT Tue Aug 13 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST/MID MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. ...Midwest/Mid Mississippi Valley into the Southern/Central Plains... An initially weak upper trough should gradually consolidate and form into a closed low over the Upper Midwest on Thursday. A corresponding increase in westerly mid-level flow should occur across parts of the Midwest into the mid MS Valley. At the surface, a weak low should gradually occlude as it meanders over the Upper Midwest beneath the developing upper low. Although low-level convergence along an associated cold front extending southwestward from the surface low should remain fairly limited, a rather moist and unstable airmass should be in place ahead of the front by Thursday afternoon across parts of the Midwest and mid MS Valley. Early day convection should move eastward across these areas and weaken, with ample daytime heating in its wake. This heating combined with modestly steepened mid-level lapse rates will contribute to a strongly, and potentially extremely, unstable airmass. Increasing mid-level flow through the day should support strengthening deep-layer shear as well, with various NAM/GFS forecast soundings showing a veering wind profile with height through mid levels. This favorable thermodynamic and kinematic environment should support a threat for organized severe thunderstorms, including the potential for supercells and associated large hail threat. Sufficient low-level shear may also exist for a couple of tornadoes. However, the weak low-level convergence along the front leads to some uncertainty in overall thunderstorm coverage and placement. Regardless, a Slight Risk has been included where most guidance shows a convective QPF signal Thursday afternoon through late evening. Some chance exists for a bowing cluster to develop eastward across the Midwest, although confidence in this scenario remains fairly low. A Marginal Risk extends southwestward along the length of the weak front/wind shift into parts of the southern/central Plains. Although coverage of severe thunderstorms may remain more isolated across these regions, a well-mixed boundary layer could still support severe wind gusts with any high-based convection that can develop. ..Gleason.. 08/13/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook RESENT 1 NWS Storm Prediction Center Norman OK 0315 AM CDT Tue Aug 13 2024 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST/MID MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms appear possible across parts of the Midwest and mid Mississippi Valley on Thursday. ...Midwest/Mid Mississippi Valley into the Southern/Central Plains... An initially weak upper trough should gradually consolidate and form into a closed low over the Upper Midwest on Thursday. A corresponding increase in westerly mid-level flow should occur across parts of the Midwest into the mid MS Valley. At the surface, a weak low should gradually occlude as it meanders over the Upper Midwest beneath the developing upper low. Although low-level convergence along an associated cold front extending southwestward from the surface low should remain fairly limited, a rather moist and unstable airmass should be in place ahead of the front by Thursday afternoon across parts of the Midwest and mid MS Valley. Early day convection should move eastward across these areas and weaken, with ample daytime heating in its wake. This heating combined with modestly steepened mid-level lapse rates will contribute to a strongly, and potentially extremely, unstable airmass. Increasing mid-level flow through the day should support strengthening deep-layer shear as well, with various NAM/GFS forecast soundings showing a veering wind profile with height through mid levels. This favorable thermodynamic and kinematic environment should support a threat for organized severe thunderstorms, including the potential for supercells and associated large hail threat. Sufficient low-level shear may also exist for a couple of tornadoes. However, the weak low-level convergence along the front leads to some uncertainty in overall thunderstorm coverage and placement. Regardless, a Slight Risk has been included where most guidance shows a convective QPF signal Thursday afternoon through late evening. Some chance exists for a bowing cluster to develop eastward across the Midwest, although confidence in this scenario remains fairly low. A Marginal Risk extends southwestward along the length of the weak front/wind shift into parts of the southern/central Plains. Although coverage of severe thunderstorms may remain more isolated across these regions, a well-mixed boundary layer could still support severe wind gusts with any high-based convection that can develop. ..Gleason.. 08/13/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0344 AM CDT Tue Aug 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Upper ridging over the southern tier of the CONUS should be suppressed by a slow moving upper trough/low over the Upper Midwest and Great Lakes on Day 4/Friday. Moderate to locally strong instability should once again be in place along/ahead of a weak front. Sufficient mid-level flow and related deep-layer shear should exist to support at least an isolated severe threat across parts of the OH Valley/Midwest into the mid MS Valley and southern/central Plains. However, the presence of prior convection and only weak low-level convergence along the front lend low confidence in delineating a corridor of greater severe potential across these regions Friday afternoon/evening. Have therefore not included a 15% severe area at this time. For this weekend into early next week, an upper low should develop and remain over the eastern Pacific, off the Northwest Coast. Upper ridging is forecast to build over much of the West and Rockies/Plains, with upper troughing persisting over the eastern states. Some severe threat may continue each day across parts of the Plains into the Southeast and eastern states, along and south/east of a weak front. But, the overall synoptic pattern suggests limited predictability in highlighting focused areas of greater severe potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0344 AM CDT Tue Aug 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Upper ridging over the southern tier of the CONUS should be suppressed by a slow moving upper trough/low over the Upper Midwest and Great Lakes on Day 4/Friday. Moderate to locally strong instability should once again be in place along/ahead of a weak front. Sufficient mid-level flow and related deep-layer shear should exist to support at least an isolated severe threat across parts of the OH Valley/Midwest into the mid MS Valley and southern/central Plains. However, the presence of prior convection and only weak low-level convergence along the front lend low confidence in delineating a corridor of greater severe potential across these regions Friday afternoon/evening. Have therefore not included a 15% severe area at this time. For this weekend into early next week, an upper low should develop and remain over the eastern Pacific, off the Northwest Coast. Upper ridging is forecast to build over much of the West and Rockies/Plains, with upper troughing persisting over the eastern states. Some severe threat may continue each day across parts of the Plains into the Southeast and eastern states, along and south/east of a weak front. But, the overall synoptic pattern suggests limited predictability in highlighting focused areas of greater severe potential. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0157 AM CDT Tue Aug 13 2024 Valid 141200Z - 151200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level shortwave trough is expected to approach the northwestern California coast on D2/Wednesday, with much of the Western U.S. characterized by weak, zonal mid-level flow. This trough could bring some forcing for thunderstorm development overnight into Thursday morning across northern California into southern Oregon, but PWAT values > 0.8 and Most Unstable parcel originating at temps colder than 0C leave some uncertainty on where dry thunder highlights might be needed. Surface winds are forecast to remain well below Critical highlight criteria across the western U.S., though some locally Elevated fire-weather conditions are possible across portions of southern Nevada, northwest Arizona, and southern Utah. These conditions will be confined to local topography, and fuels across much of the southern Great Basin are not receptive enough to wildfire spread (due to recent wetting rainfall) to warrant highlights at this time. ..Halbert/Wendt.. 08/13/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0157 AM CDT Tue Aug 13 2024 Valid 141200Z - 151200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level shortwave trough is expected to approach the northwestern California coast on D2/Wednesday, with much of the Western U.S. characterized by weak, zonal mid-level flow. This trough could bring some forcing for thunderstorm development overnight into Thursday morning across northern California into southern Oregon, but PWAT values > 0.8 and Most Unstable parcel originating at temps colder than 0C leave some uncertainty on where dry thunder highlights might be needed. Surface winds are forecast to remain well below Critical highlight criteria across the western U.S., though some locally Elevated fire-weather conditions are possible across portions of southern Nevada, northwest Arizona, and southern Utah. These conditions will be confined to local topography, and fuels across much of the southern Great Basin are not receptive enough to wildfire spread (due to recent wetting rainfall) to warrant highlights at this time. ..Halbert/Wendt.. 08/13/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0146 AM CDT Tue Aug 13 2024 Valid 131200Z - 141200Z ...Synopsis... A mid-level shortwave trough and associated vorticity maximum will move northeastward from California into eastern Oregon and Washington. In response to the approaching trough, southerly low-level flow will transport modified monsoonal moisture northward into portions of eastern Oregon and into Idaho, where modest PWAT values of 0.6-0.8 will support the occurrence of dry thunderstorms. Some locally enhanced fire-weather conditions are possible across portions of the Great Basin, particularly in northeastern Nevada. However, in the absence of any large-scale pressure gradients, any stronger winds will be diurnally/terrain-driven. ...Dry Thunderstorms... Two rounds of dry thunderstorms are possible across portions of eastern Oregon and into Idaho, where some dry thunder will be ongoing at the start of the forecast period, and another round should develop around 21Z. Current forecast guidance places more confidence in the later-period thunder, rather than the early-period thunder. However, with modest PWAT values and storm motions of about 25-30 kts, wetting rainfall will be limited over fuels that are receptive to new ignitions. ...Dry/Windy... Some locally elevated fire-weather conditions are possible across northeastern Nevada. While fuels guidance suggests some receptiveness to new ignitions, and relative humidity values will fall to 15-20%, sustained winds reaching elevated criteria will be localized to terrain features. This will preclude any highlight areas at this time. ..Halbert/Wendt.. 08/13/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue Aug 13 2024 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHEAST KANSAS...EASTERN NEBRASKA...SOUTHWEST IOWA...AND NORTHWEST MISSOURI... ...SUMMARY... Isolated to scattered severe thunderstorms should occur Wednesday across parts of the northern/central Plains into the mid Missouri Valley, with greater potential for large hail and damaging winds across parts of northeast Kansas, eastern Nebraska, southwest Iowa, and northwest Missouri. ...Northern/Central Plains into the Mid Missouri Valley... Thunderstorms that should be ongoing at the start of the period Wednesday morning across parts of the mid MO Valley should gradually decrease in coverage and intensity through the early afternoon as a southwesterly low-level jet and related warm advection slowly weakens. Upper ridging is forecast to remain prominent through the period across the lower MS Valley/Southeast into the Midwest and Great Lakes. Upstream, weak upper troughing is expected to become established over the northern/central Plains, with multiple low-amplitude mid-level perturbations forecast to move eastward across these regions. At the surface, a broad warm sector should be in place along/ahead of a weak front/lee trough. Most guidance suggests that multiple weak surface lows should generally consolidate over parts of central/eastern NE/KS by early Wednesday evening. Greater low-level moisture, characterized by upper 60s to low 70s surface dewpoints, should be in place across parts of the central Plains into the mid MO Valley. This moisture is forecast to advect northward in tandem with a sharpening warm front through the day, although considerable uncertainty still exists with how far north into IA the warm sector will be able to develop. Robust thunderstorms should develop by late Wednesday afternoon across parts of eastern NE and northeast KS in the vicinity of a weak surface low and triple point. Moderate to strong instability will likely be in place due to ample daytime heating of the rather moist airmass, along with somewhat steepened mid-level lapse rates. Even though mid/upper-level flow is forecast to be only modestly enhanced, veering and gradual strengthening of the wind field with height should support enough deep-layer shear for a mix of multicells and supercells initially. Both large hail and severe/damaging winds appear possible. A low-level jet is also forecast to strengthen Wednesday evening across eastern NE/KS into IA. Any supercell that can remain at surface based could also pose some threat for a tornado across this area given strengthening low-level shear Wednesday evening. Otherwise, a bowing cluster may eventually develop and pose more of a damaging wind threat as it spreads east-northeastward across the mid MO Valley Wednesday evening and overnight. Other strong to severe thunderstorms appear possible across a broader portion of the northern/central Plains, although instability is forecast to generally become weaker with northward and westward extent. Still, weak to locally moderate instability and sufficient deep-layer shear for modestly organized updrafts should exist across much of the warm sector Wednesday afternoon and evening. An isolated threat for both hail and strong to severe wind gusts remains apparent, and the Marginal Risk has been expanded in multiple areas to account for latest guidance trends in where strong to severe convection may develop. ..Gleason.. 08/13/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0103 AM CDT Tue Aug 13 2024 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE INTERMOUNTAIN WEST ACROSS THE HIGH PLAINS INTO THE CENTRAL PLAINS...AND ACROSS THE SOUTH CAROLINA AREA... ...SUMMARY... Isolated severe thunderstorms are possible Tuesday across parts of the eastern Great Basin/northern Intermountain region into the northern/central High Plains and central Plains, as well as portions of South Carolina and vicinity. ...The Intermountain Region to the central and northern High Plains... Several weak disturbances/vorticity maxima are forecast to move through the broader/weakly cyclonic flow field that will persist across the West today. Daytime heating will support modest CAPE development -- greatest from Utah north across eastern Idaho, and over the High Plains. Scattered afternoon storm development is expected across a broad area, though with shear generally limited -- thus limiting overall severe potential. The most favorable CAPE/shear combination is expected from southwestern Montana southward into Utah, where a couple of supercells could evolve. Hail and locally damaging wind gusts would be possible, though questions regarding overall coverage of the stronger convection precludes an upgrade to slight risk at this time. Convection should weaken through the evening, as the airmass gradually stabilizes. Storms evolving across the High Plains may linger into the overnight hours, with convection across Colorado possibly growing upscale into an eastward-moving cluster. Potential for locally damaging wind gusts during the afternoon may therefore persist after dark, spreading across the High Plains and into Kansas through the evening and into the overnight hours. ...Central Plains... As a 40-plus kt south-southwesterly low-level jet develops across the central Plains during the evening, elevated storm development is expected north of a west-to-east surface front forecast to reside over central Kansas. With moderate CAPE expected atop the cool/stable boundary layer north of the front, a few stronger storms are expected to evolve, potentially capable of producing hail at or exceeding severe levels. Strong/gusty outflow winds will also be possible, particularly with storms nearer the frontal zone. ...South Carolina... Despite weak lapse rates aloft, some afternoon destabilization is forecast in the vicinity of a weak/remnant front progged to lie across South Carolina during the afternoon. The front should focus isolated to widely scattered afternoon storms, which should move southeastward on account of moderate mid-level west-northwesterly flow atop the area. With the moderate northwesterlies contributing to sufficient shear for at least multicell organization, a few stronger storms are expected -- possibly congealing into a southeastward-moving cluster by late afternoon. The more vigorous storms will be capable of strong to possibly locally damaging wind gusts, before convection weakens/move offshore. ..Goss/Halbert.. 08/13/2024 Read more

MD 1890 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR EASTERN COLORADO INTO WESTERN KANSAS...AND THE FAR WESTERN TEXAS AND OKLAHOMA PANHANDLES
Mesoscale Discussion 1890 NWS Storm Prediction Center Norman OK 0826 PM CDT Mon Aug 12 2024 Areas affected...Eastern Colorado into Western Kansas...and the far western Texas and Oklahoma Panhandles Concerning...Severe potential...Watch unlikely Valid 130126Z - 130330Z Probability of Watch Issuance...20 percent SUMMARY...Convection has organized into a few linear segments as storms have progressed eastward onto the High Plains of eastern Colorado and the far northwestern TX/western OK Panhandles. These storms could be capable of a few severe gusts, but are moving into a stabilizing environment. Weather Watch issuance is not likely at this time. DISCUSSION...Afternoon thunderstorms have begun to coalesce into two linear convective segments -- one in eastern Colorado, the other in the far western Oklahoma Panhandle -- that will be capable of a few severe gusts this evening. The greatest threat for severe winds will be along the leading edge of any developing bow echoes, though the stabilizing nocturnal boundary-layer could inhibit some of the higher-momentum air from reaching the surface. Additionally, the observed 00Z DDC sounding, along with SPC mesoanalysis, suggests both MCSs are moving into increasing MUCINH that will likely cause convection to weaken with eastward extent. Given these factors, Weather Watch issuance appears unlikely at this time. ..Halbert/Wendt/Edwards.. 08/13/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DDC...GLD...AMA...PUB...BOU...ABQ... LAT...LON 35690251 35850286 35980317 36080337 36330357 37670434 38360458 38500470 38640445 38760430 39040412 39240396 39410374 39430358 39340317 39200269 39090222 38860163 38700123 38370091 37950086 37440079 37000081 36510084 36130098 35870134 35750184 35690251 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0805 PM CDT Mon Aug 12 2024 Valid 130100Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL HIGH PLAINS VICINITY... ...SUMMARY... Isolated severe thunderstorms may persist over the next several hours across the central High Plains area. ...Central High Plains vicinity... Scattered strong/isolated severe storms are ongoing at this time across portions of the central Plains -- from eastern Colorado south to northeastern New Mexico. A modestly moist/moderately unstable airmass persists across this area, with evening RAOBs and RAP-based objective analysis indicating that 1000 to 2000 J/kg mixed-layer CAPE persists. Though mid-level westerlies remain relatively weak (less than 30 kt), low-level easterly flow is contributing to sufficient 0-6km shear for organized storms -- including a couple of supercells. Some clustering of storms is occurring near/east of the Palmer Ridge, with some potential for eastward propagation toward lower elevations -- including embedded risk for locally strong/damaging winds and possibly hail. Still, overall risk should remain limited as the environment slowly stabilizes this evening, and thus will maintain only MRGL risk through the evening. ..Goss.. 08/13/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0805 PM CDT Mon Aug 12 2024 Valid 130100Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL HIGH PLAINS VICINITY... ...SUMMARY... Isolated severe thunderstorms may persist over the next several hours across the central High Plains area. ...Central High Plains vicinity... Scattered strong/isolated severe storms are ongoing at this time across portions of the central Plains -- from eastern Colorado south to northeastern New Mexico. A modestly moist/moderately unstable airmass persists across this area, with evening RAOBs and RAP-based objective analysis indicating that 1000 to 2000 J/kg mixed-layer CAPE persists. Though mid-level westerlies remain relatively weak (less than 30 kt), low-level easterly flow is contributing to sufficient 0-6km shear for organized storms -- including a couple of supercells. Some clustering of storms is occurring near/east of the Palmer Ridge, with some potential for eastward propagation toward lower elevations -- including embedded risk for locally strong/damaging winds and possibly hail. Still, overall risk should remain limited as the environment slowly stabilizes this evening, and thus will maintain only MRGL risk through the evening. ..Goss.. 08/13/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0218 PM CDT Mon Aug 12 2024 Valid 141200Z - 151200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL/NORTHERN PLAINS INTO THE MID-MISSOURI VALLEY... ...SUMMARY... At least isolated severe thunderstorms may occur Wednesday across parts of the northern/central Plains into the mid Missouri Valley. ...Synopsis... A band of elevated thunderstorms will likely be ongoing at the beginning of the period across a broad region of isentropic ascent from southeast South Dakota to southern Missouri. As the low-level jet weakens through the morning, expect the intensity of these storms to lessen as they move east into a more stable airmass. To the west, an unstable airmass is forecast across much of the central and northern Plains in the vicinity of a broad surface trough. At least weak to moderate instability is forecast with the potential for greater instability in eastern NE/KS where higher dewpoints (upper 60s to low 70s) are forecast. The breakdown of the upper-level ridge will lead to height falls across much of the central and northern Plains. Given the unstable environment across much of the area, this weak upper-level forcing combined with the surface trough will likely result in scattered thunderstorms across much of the central and northern Plains Wednesday afternoon/evening. A more focused threat may exist farther south across eastern Kansas in Nebraska. Some enhancement of the mid-level flow ahead of the ridge breakdown may lead to a localized region of more favorable wind shear, co-located with the forecast greater instability. If this occurs, particularly with the development of a surface low as forecast by the NAM/ECMWF, a locally greater severe weather threat may occur across this region. At this time, uncertainty in the mesoscale features which will impact this potential are too great to warrant higher severe weather probabilities. ..Bentley.. 08/12/2024 Read more

No watches are valid as of Mon Aug 12 23:50:01 UTC 2024.

MD 1888 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR NORTH-CENTRAL MONTANA
Mesoscale Discussion 1888 NWS Storm Prediction Center Norman OK 0513 PM CDT Mon Aug 12 2024 Areas affected...North-central Montana Concerning...Severe potential...Watch unlikely Valid 122213Z - 130015Z Probability of Watch Issuance...5 percent SUMMARY...A potential will exist for marginally severe gusts and hail early this evening across parts of north-central Montana. No watch issuance is anticipated. DISCUSSION...The latest water-vapor imagery shows a subtle shortwave trough over the northern Rockies, embedded in southwest mid-level flow. At the surface, a mesolow is analyzed over north-central Montana, with upslope east-southeasterly flow located across much of northern and eastern Montana. Isolated thunderstorms have developed near and to the north of the low along a narrow corridor of instability, where the RAP is estimating SBCAPE in the 1000 to 1500 J/kg range. Short-term forecast soundings in north-central Montana early this evening have a relatively dry boundary layer, but show steep lapse rates and moderate deep-layer shear. This may be enough for a marginal severe threat for a few hours. Strong gusts and hail will be possible. ..Broyles/Edwards.. 08/12/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GGW...TFX... LAT...LON 47221015 47150938 47340862 47740811 48320827 48880909 48961048 48861165 48541205 48011188 47221015 Read more

MD 1889 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR NORTHEASTERN COLORADO
Mesoscale Discussion 1889 NWS Storm Prediction Center Norman OK 0634 PM CDT Mon Aug 12 2024 Areas affected...Northeastern Colorado Concerning...Severe potential...Watch unlikely Valid 122334Z - 130100Z Probability of Watch Issuance...5 percent SUMMARY...A supercell thunderstorm capable of damaging winds, hail, and perhaps a tornado is tracking southward across portions of northeast Colorado. Given the isolated nature of this storm, weather watch issuance is not likely. DISCUSSION...The severe weather threat associated with a southward-moving supercell in northeast Colorado may persist for the next 1-2 hours. The storm has exhibited signs of prolonged low-level rotation, has produced 2.00 inch hail, and is moving into an environment that will continue to support updraft rotation. Forecast proximity hodographs indicate there is sufficient curvature of the low-level flow and streamwise vorticity to support continued low-level mesocyclone development and cycling. Both the curvature and magnitude of the low-level hodograph is expected to increase as the nocturnal low-level jet strengthens with the decoupling of the boundary-layer. However, recent radar trends suggest the storm is struggling to stay ahead of its own outflow, where temperatures are 15-20 F cooler than unmodified inflow. This supercell will likely undergo several phases of organized low-level rotation, followed by surging outflow, until the boundary-layer eventually stabilizes this evening and convection becomes more elevated in nature. ..Halbert/Wendt/Edwards.. 08/12/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BOU... LAT...LON 40790427 40960414 40980387 40870363 40680344 40460333 40260326 40120319 39920338 39830370 39860389 40000414 40140421 40330425 40510427 40790427 Read more