SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1115 AM CST Tue Nov 12 2024 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER MISSISSIPPI VALLEY/CENTRAL GULF COAST REGION...AND COASTAL PORTIONS OF PACIFIC NORTHWEST... ...SUMMARY... A marginal tornado/wind threat is apparent on Wednesday afternoon into Wednesday night across a part of the central Gulf Coast States. Thunderstorms with strong to locally severe gusts are also possible near the immediate coasts of Washington, Oregon, and northern California. ...Synopsis... A shortwave trough is forecast to move from the Plains through the MS Valley on Wednesday, becoming more negatively tilted as it does. An occluded surface low associated with this system will begin the period over the mid MO Valley before moving eastward across IA and reaching the northern IL early Thursday morning. More consequently for the severe-weather potential, a secondary triple-point low is expected to progress eastward across the northern portion of the Southeast states, along the northern edge of an eastward-evolving warm sector. Cold front associated with this low will gradually move eastward across the Southeast states during the day. Farther west, an upper-level trough is forecast to progress farther inland across the western CONUS, as an embedded shortwave trough moves across northern CA into the interior Northwest/northern Great Basin. ...Lower Mississippi Valley/Central Gulf Coast... General expectation is for a triple-point surface low to evolve over the Mid-South vicinity through the early afternoon as low-level moisture continues to advect northward across the central Gulf Coast region. Dewpoints in the upper 60s/low 70s are anticipated ahead of this low and associated cold front. The airmass is expected to destabilize amid this low-level moisture, but overall buoyancy will still be modest given the lack of steep lapse rates. The combination of destabilization and increasing ascent is forecast to result in thunderstorm development across the warm sector, but along and ahead of the eastward-progressing cold front. The stronger shear will likely be displaced north of the stronger buoyancy, but enough shear is expected across the warm sector to support organized storms if updrafts can persist and deepen. This evolution could support a few marginal supercells and/or stronger clusters during the afternoon and evening, with a threat of locally damaging winds and possibly a tornado or two. Elevated storms will also be possible through the day/evening to the north of the richer surface moisture. While effective shear will be sufficient for a few strong elevated storms, the severe potential with northward extent will tend to be limited by weak midlevel lapse rates and generally marginal buoyancy. ...WA/OR/Northern CA coasts... Cold mid-level temperatures (i.e. -24 to -28 deg C at 500 mb) associated with the upper trough are expected to spread eastward throughout the day. These cold mid-level temperatures and associated steep mid-level lapse rates will contribute to modest buoyancy along the coastal portions of the Pacific Northwest. Highest storm coverage is anticipated over the northern CA coast vicinity from the late morning into the early afternoon along as the frontal band moves through, but persistent forcing for ascent within this modestly buoyant airmass is expected to result in more cellular storms throughout the remainder of the afternoon and evening. A more linear mode is anticipated within the frontal band, with a few convectively enhanced gusts possible. Low-topped cellular activity is anticipated in the wake of the frontal band, with a few instances of small hail, and potentially even a brief tornado, possible. ..Mosier.. 11/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1024 AM CST Tue Nov 12 2024 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms may impact parts of the Texas South Plains and Oklahoma/Texas Panhandle vicinity this evening, possibly accompanied by some risk for hail and gusty winds. ...Southern High Plains... An upper-level trough over the eastern Great Basin/Four Corners at midday will continue eastward toward the south-central High Plains tonight. Gradual lee-side cyclogenesis will occur particularly late today into tonight, with a sharpening southern High Plains dryline/lee trough, with an eastward-moving Pacific cold front that will overtake the dryline/lee trough from west-to-east tonight. Modest-caliber low-level moisture return will occur north-northwestward across the southern High Plains, with surface dewpoints tending to remain limited to the upper 40s/lower 50s F into this evening. It still appears likely that deep convective potential across northwest Texas and the Oklahoma/Texas Panhandles will remain limited through peak heating, owing to the moisture limitations and a persistent capping inversion. Isolated thunderstorm development will become more probable after sunset as lift associated with a strengthening low-level jet increases, and as the surface cold front overtakes the lee trough. While MUCAPE is expected to remain rather weak (generally 500-1000 J/kg or less), strong deep-layer shear will support organized updrafts with any sustained convection. Isolated hail appears to be the main threat, as thunderstorms should have a tendency to remain slightly elevated. But, some chance for strong/gusty winds may also exist. The window for severe hail should remain small in space and time this evening, as convection will likely grow upscale fairly quickly. Even so, small hail may occur farther north/east into parts of Kansas and Oklahoma overnight into early Wednesday morning. ..Guyer/Lyons.. 11/12/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1024 AM CST Tue Nov 12 2024 Valid 121630Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms may impact parts of the Texas South Plains and Oklahoma/Texas Panhandle vicinity this evening, possibly accompanied by some risk for hail and gusty winds. ...Southern High Plains... An upper-level trough over the eastern Great Basin/Four Corners at midday will continue eastward toward the south-central High Plains tonight. Gradual lee-side cyclogenesis will occur particularly late today into tonight, with a sharpening southern High Plains dryline/lee trough, with an eastward-moving Pacific cold front that will overtake the dryline/lee trough from west-to-east tonight. Modest-caliber low-level moisture return will occur north-northwestward across the southern High Plains, with surface dewpoints tending to remain limited to the upper 40s/lower 50s F into this evening. It still appears likely that deep convective potential across northwest Texas and the Oklahoma/Texas Panhandles will remain limited through peak heating, owing to the moisture limitations and a persistent capping inversion. Isolated thunderstorm development will become more probable after sunset as lift associated with a strengthening low-level jet increases, and as the surface cold front overtakes the lee trough. While MUCAPE is expected to remain rather weak (generally 500-1000 J/kg or less), strong deep-layer shear will support organized updrafts with any sustained convection. Isolated hail appears to be the main threat, as thunderstorms should have a tendency to remain slightly elevated. But, some chance for strong/gusty winds may also exist. The window for severe hail should remain small in space and time this evening, as convection will likely grow upscale fairly quickly. Even so, small hail may occur farther north/east into parts of Kansas and Oklahoma overnight into early Wednesday morning. ..Guyer/Lyons.. 11/12/2024 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0910 AM CST Tue Nov 12 2024 Valid 121700Z - 131200Z The Elevated area in the Northeast was expanded southward based on current observations (winds gusting 20-45 mph, RH of 40-60%) and the latest high-resolution forecast guidance. RH and temperatures will be close to elevated criteria, but wind gusts of 25-50 mph and near to record setting high fire danger will create elevated to locally critical fire weather conditions in the outlook area. The Elevated area in southern California remains on track. Overnight RH recovery was moderate to excellent with north-northwest wind gusts of 25-60 mph early this morning. The strongest winds will struggle to overlap with elevated/critical RH, but elevated fire weather conditions remain likely in portions of the Transverse Ranges/vicinity, primarily on southern/ocean-facing slopes. ..Nauslar.. 11/12/2024 .PREV DISCUSSION... /ISSUED 0158 AM CST Tue Nov 12 2024/ ...Synopsis... ...Southern California... A weak cold front will move across southern California through the morning. Behind this frontal passage, gusty northwest winds will be enhanced near favored downslope terrain features across Santa Barbra and Ventura Counties. Relative humidity will hover around elevated thresholds. Relative humidity will decrease, especially at mid/upper slopes, below critical relative humidity thresholds with poor overnight recovery tonight into D2/Wednesday morning. However, winds are expected to weaken below thresholds during this period. An Elevated delineation was maintained with this outlook. ...New England... Gusty northwesterly flow will overlap relative humidity reductions to 35-40 percent across New England this afternoon. Though relative humidity will be marginal, recent fire activity has shown fuels in this region are receptive to fire spread with drought conditions and very little recent rainfall. An Elevated delineation was included to cover this threat, given the potential for strong and gusty winds. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0652 AM CST Tue Nov 12 2024 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN HIGH PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms may impact parts of the Texas South Plains and Oklahoma/Texas Panhandle vicinity this evening, perhaps accompanied by some risk for hail and gusty winds. ...Southern High Plains... An upper trough over the Great Basin will advance eastward across the Rockies today, reaching the Plains late tonight into early Wednesday morning. Large-scale ascent preceding this feature will encourage modest surface cyclogenesis across parts of the northern/central High Plains. Low-level moisture will return northward today over portions of the southern High Plains, although its depth and quality will remain limited. It appears unlikely that convection will develop this afternoon across northwest TX into the OK/TX Panhandles, as a cap and weak instability should inhibit initiation. A somewhat better opportunity for thunderstorms will exist this evening across this area, mainly around/after 00-04Z, as warm advection and lift associated with a strengthening low-level jet increases, and as a surface cold front overtakes the lee trough. While MUCAPE is expected to remain rather weak (generally 500-1000 J/kg or less), strong deep-layer shear will support organized updrafts with any sustained convection. Isolated hail appears to be the main threat, as thunderstorms should have a tendency to remain slightly elevated. But, some chance for strong/gusty winds may also exist. The window for severe hail should remain small in space and time this evening, as convection will likely grow upscale fairly quickly. Even so, small hail may occur farther north/east into parts of KS and OK overnight into early Wednesday morning. ..Gleason/Bentley.. 11/12/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0333 AM CST Tue Nov 12 2024 Valid 151200Z - 201200Z ...DISCUSSION... Guidance still generally suggests some organized severe potential may evolve across the south-central Plains and vicinity early next week, though uncertainty remains high regarding the timing and intensity of embedded shortwave troughs and the details regarding low-level moisture return and destabilization. On D5/Saturday, a mid/upper-level shortwave trough is forecast to emerge from the deep, positively tilted trough over the West and move across the northern Plains, accompanied by a deepening surface low. While severe potential appears minimal on Saturday, the ejecting wave is forecast to initiate low-level moisture return into the southern Plains, which will continue into D6/Sunday and D7/Monday. For D6/Sunday into D7/Monday, the most important feature related to severe potential will be a shortwave trough that may briefly evolve into a closed mid/upper-level low somewhere over the Southwest, before ejecting east-northeastward. Recent runs of the deterministic ECMWF/GFS are in relatively good agreement in depicting a negatively tilted shortwave trough ejecting into the south-central Plains on D7/Monday. However, spread among GEFS ensemble members remains rather high regarding the timing and evolution of shortwaves into early next week, while the ECMWF is less aggressive with low-level moisture return, showing only very minimal destabilization in advance of the ejecting shortwave trough on D7/Monday. Given the uncertainties regarding both shortwave timing and magnitude of moisture return/destabilization, confidence is too low to delineate a 15 percent area over some portion of the south-central Plains for D7/Monday, the day which seems to have the greatest relative potential at this time. It remains possible that some severe threat could emerge as soon as D6/Sunday, and/or potentially persist into D8/Tuesday. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0333 AM CST Tue Nov 12 2024 Valid 151200Z - 201200Z ...DISCUSSION... Guidance still generally suggests some organized severe potential may evolve across the south-central Plains and vicinity early next week, though uncertainty remains high regarding the timing and intensity of embedded shortwave troughs and the details regarding low-level moisture return and destabilization. On D5/Saturday, a mid/upper-level shortwave trough is forecast to emerge from the deep, positively tilted trough over the West and move across the northern Plains, accompanied by a deepening surface low. While severe potential appears minimal on Saturday, the ejecting wave is forecast to initiate low-level moisture return into the southern Plains, which will continue into D6/Sunday and D7/Monday. For D6/Sunday into D7/Monday, the most important feature related to severe potential will be a shortwave trough that may briefly evolve into a closed mid/upper-level low somewhere over the Southwest, before ejecting east-northeastward. Recent runs of the deterministic ECMWF/GFS are in relatively good agreement in depicting a negatively tilted shortwave trough ejecting into the south-central Plains on D7/Monday. However, spread among GEFS ensemble members remains rather high regarding the timing and evolution of shortwaves into early next week, while the ECMWF is less aggressive with low-level moisture return, showing only very minimal destabilization in advance of the ejecting shortwave trough on D7/Monday. Given the uncertainties regarding both shortwave timing and magnitude of moisture return/destabilization, confidence is too low to delineate a 15 percent area over some portion of the south-central Plains for D7/Monday, the day which seems to have the greatest relative potential at this time. It remains possible that some severe threat could emerge as soon as D6/Sunday, and/or potentially persist into D8/Tuesday. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0210 AM CST Tue Nov 12 2024 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms are not currently expected on Thursday. ...Synopsis... A mid/upper-level shortwave trough initially over parts of the Great Lakes/Ohio Valley is forecast to turn southeastward and intensify on Thursday. In response to this system, a surface low is forecast to develop and deepen somewhere near the GA/Carolina coasts by Thursday evening. Farther west, a deep mid/upper-level trough will continue to move further inland across the western CONUS through the period. ...Central/northeast Gulf Coast vicinity... Rich low-level moisture will be in place ahead of a cold front during the morning/afternoon across parts of the central and northeast Gulf Coast vicinity, and thunderstorms may persist from late in the D2/Wednesday period and/or redevelop from the morning into at least the early afternoon. Guidance generally suggests that low-level flow will tend to veer and weaken with time in areas where richer moisture is in place, while weak midlevel lapse rates will limit instability. With the spatial extent of surface-based convective potential expected to be constrained and the environment forecast to become less favorable with time, organized severe potential appears too limited/uncertain to include probabilities. However, a strong storm or two will be possible, especially if convection from late D2/Wednesday is able to remain somewhat organized into the D3/Thursday forecast period. ...Coastal Carolinas... Considerable uncertainty remains regarding the evolution of the low that is forecast to deepen somewhere near the GA/Carolina coasts later in the forecast period. Some guidance suggests potential for richer low-level moisture and surface-based buoyancy to approach parts of the Coastal Carolinas, in the presence of strong deep-layer shear. While it currently appears that the bulk of organized convection will remain offshore, this area will continue to be monitored for development of an appreciable severe threat in the vicinity of the coast. ..Dean.. 11/12/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0200 AM CST Tue Nov 12 2024 Valid 131200Z - 141200Z ...Synopsis... Gusty post-frontal off-shore flow will continue across portions of the Northeast from far eastern PA and southern NJ extending northeast through southern New England. A very dry air mass will remain in place with relative humidity reductions to around 30-35 percent likely. Given the drought conditions and receptive fuels in this region, an Elevated delineation was maintained with this outlook. Locally Critical conditions may be possible, though the limited spatial extent of this threat precludes the need to include a Critical area at this time. ..Thornton.. 11/12/2024 ...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 0158 AM CST Tue Nov 12 2024 Valid 121200Z - 131200Z ...Synopsis... ...Southern California... A weak cold front will move across southern California through the morning. Behind this frontal passage, gusty northwest winds will be enhanced near favored downslope terrain features across Santa Barbra and Ventura Counties. Relative humidity will hover around elevated thresholds. Relative humidity will decrease, especially at mid/upper slopes, below critical relative humidity thresholds with poor overnight recovery tonight into D2/Wednesday morning. However, winds are expected to weaken below thresholds during this period. An Elevated delineation was maintained with this outlook. ...New England... Gusty northwesterly flow will overlap relative humidity reductions to 35-40 percent across New England this afternoon. Though relative humidity will be marginal, recent fire activity has shown fuels in this region are receptive to fire spread with drought conditions and very little recent rainfall. An Elevated delineation was included to cover this threat, given the potential for strong and gusty winds. ..Thornton.. 11/12/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1257 AM CST Tue Nov 12 2024 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER MS VALLEY AND NORTHEAST GULF COAST...FOR COASTAL WA/OR/NORTHERN CA... ...SUMMARY... A marginal tornado/wind threat is apparent on Wednesday afternoon into Wednesday night across a part of the central Gulf Coast States. Thunderstorms with strong to locally severe gusts are also possible near the immediate coasts of Washington, Oregon, and northern California. ...Synopsis... A mid/upper-level shortwave trough is forecast to move eastward from the Great Plains toward the Midwest and OH/TN Valleys on Wednesday. In conjunction with this shortwave trough, a weak surface low will move from the east-central Plains toward the Great Lakes region, as a trailing cold front moves through parts of the middle/lower MS Valley. Farther west, a deep mid/upper-level trough will progress farther inland across the western CONUS, as an embedded shortwave moves across northern CA into the interior Northwest. ...Lower Mississippi Valley/Central Gulf Coast region... Rich low-level moisture (with upper 60s to lower 70s F dewpoints) is forecast to gradually spread northward across the lower MS Valley region from later in the D1/Tuesday period into D2/Wednesday. Weak lapse rates will tend to limit instability, while stronger mid/upper-level flow will generally remain north of the richer moisture. However, deep-layer shear will likely become at least marginally supportive of organized storms, while some enhancement to low-level flow/shear is forecast as the shortwave trough to the north glances the region. This evolution could support a few marginal supercells and/or stronger clusters during the afternoon and evening, with a threat of locally damaging winds and possibly a tornado or two. Elevated storms will also be possible through the day/evening to the north of the richer surface moisture. While effective shear will be sufficient for a few strong elevated storms, the severe potential with northward extent will tend to be limited by weak midlevel lapse rates and generally marginal MUCAPE. ...WA/OR/northern CA coasts... Cooling temperatures aloft will support weak destabilization in the vicinity of the WA/OR/northern CA coasts through the day on Wednesday. While convection will be rather low-topped, instability may become sufficient (with SBCAPE potentially in the 200-500 J/kg range) for occasional thunderstorms. The strongest low-level flow will precede the primary destabilization, but persistent and rather strong deep-layer southwesterly flow could support modestly organized line segments and/or weakly rotating cells, with a threat of isolated severe convective gusts and perhaps some small hail. A brief tornado also cannot be ruled out, though the favored location (if any) of any longer-lived rotating cells remains uncertain at this time. ..Dean.. 11/12/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1257 AM CST Tue Nov 12 2024 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER MS VALLEY AND NORTHEAST GULF COAST...FOR COASTAL WA/OR/NORTHERN CA... ...SUMMARY... A marginal tornado/wind threat is apparent on Wednesday afternoon into Wednesday night across a part of the central Gulf Coast States. Thunderstorms with strong to locally severe gusts are also possible near the immediate coasts of Washington, Oregon, and northern California. ...Synopsis... A mid/upper-level shortwave trough is forecast to move eastward from the Great Plains toward the Midwest and OH/TN Valleys on Wednesday. In conjunction with this shortwave trough, a weak surface low will move from the east-central Plains toward the Great Lakes region, as a trailing cold front moves through parts of the middle/lower MS Valley. Farther west, a deep mid/upper-level trough will progress farther inland across the western CONUS, as an embedded shortwave moves across northern CA into the interior Northwest. ...Lower Mississippi Valley/Central Gulf Coast region... Rich low-level moisture (with upper 60s to lower 70s F dewpoints) is forecast to gradually spread northward across the lower MS Valley region from later in the D1/Tuesday period into D2/Wednesday. Weak lapse rates will tend to limit instability, while stronger mid/upper-level flow will generally remain north of the richer moisture. However, deep-layer shear will likely become at least marginally supportive of organized storms, while some enhancement to low-level flow/shear is forecast as the shortwave trough to the north glances the region. This evolution could support a few marginal supercells and/or stronger clusters during the afternoon and evening, with a threat of locally damaging winds and possibly a tornado or two. Elevated storms will also be possible through the day/evening to the north of the richer surface moisture. While effective shear will be sufficient for a few strong elevated storms, the severe potential with northward extent will tend to be limited by weak midlevel lapse rates and generally marginal MUCAPE. ...WA/OR/northern CA coasts... Cooling temperatures aloft will support weak destabilization in the vicinity of the WA/OR/northern CA coasts through the day on Wednesday. While convection will be rather low-topped, instability may become sufficient (with SBCAPE potentially in the 200-500 J/kg range) for occasional thunderstorms. The strongest low-level flow will precede the primary destabilization, but persistent and rather strong deep-layer southwesterly flow could support modestly organized line segments and/or weakly rotating cells, with a threat of isolated severe convective gusts and perhaps some small hail. A brief tornado also cannot be ruled out, though the favored location (if any) of any longer-lived rotating cells remains uncertain at this time. ..Dean.. 11/12/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1132 PM CST Mon Nov 11 2024 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS EVENING ACROSS PARTS OF THE TEXAS SOUTH PLAINS AND PANHANDLE...AND ADJACENT PORTIONS OF WESTERN OKLAHOMA... ...SUMMARY... A couple of strong thunderstorms may impact parts of the Texas South Plains and Panhandle vicinity this evening, perhaps accompanied by some risk for severe weather. ...Synopsis... The westerlies appear likely to remain a bit more progressive across the eastern mid-latitude Pacific into western North America than farther downstream, from near the Atlantic Seaboard through the Atlantic. Within this regime, another significant mid-level trough, with at least a couple of embedded short wave perturbations, is forecast to approach the Pacific coast later today through tonight. As this occurs, a fairly vigorous perturbation within the southern portion of a splitting preceding trough is likely to continue east of the southern Great Basin, across and east of the southern Rockies by daybreak Wednesday. An associated cold front probably will overtake modest lee surface troughing across central and southern portions of the high plains by late tonight. Before it does, boundary-layer moisture return in a narrow plume emanating from the Rio Grande Valley, beneath steepening lower/mid-tropospheric lapse rates, might contribute to a corridor of weak to modest destabilization by late this afternoon across the Texas South Plains into Panhandle vicinity. ...Southern Great Plains... Near the leading edge of a narrow plume of elevated mixed-layer air forecast to advect north-northeastward through southern portions of the high plains, models indicate that differential surface heating may contribute to a strengthening low-level baroclinic zone across parts of the Texas South Plains and Panhandle by late this afternoon. This will probably become a focus for strengthening near-surface warm advection by early this evening, downstream of the short wave impulse progressing across the southern Rockies. This is likely to coincide with increasing low-level moisture return, which might include boundary-layer dew points as high as the lower 60s F near the immediate vicinity of the surface boundary, southward through the Texas South Plains. With regard to potential for severe storm development late this afternoon into tonight, the signal remains muted in the latest high resolution ensemble output and associated machine learning guidance. However, given the potential for at least a narrow corridor of modest boundary-layer destabilization, which may include mixed-layer CAPE on the order of 500-1000 J/kg, large-scale forcing for ascent and strengthening shear appear conducive to organized convective development. There appears a window of opportunity for the evolution of one or two boundary-layer based supercells across parts of the Texas South Plains into Panhandle, before a more general increase in thunderstorm development ensues northeastward across parts of Oklahoma and Kansas later tonight. Rooted within an increasingly elevated warm advected regime, forecast soundings suggest minimal potential for a continuing severe hail threat, once any possible boundary-layer based convective development diminishes. ..Kerr/Thornton.. 11/12/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0647 PM CST Mon Nov 11 2024 Valid 120100Z - 121200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible through tonight. ...01Z Update... ...Pacific Coast... A mid-level tongue of cold air (including 500 mb temperatures of -24 to -28C) continues to migrate inland of the Pacific coast. It appears that the axis of coldest air is in the process of shifting to the east of the Sierra Nevada and Cascades. However, latest model output suggests that the mid-level temperatures may remain cold enough to support instability sufficient for a continuing risk of occasional weak convection capable of producing lightning, mainly to the west of the Cascades, through about 06-08Z. ...Lower Great Lakes... Occasional lightning flashes have been evident with convection developing beneath a lower/mid-level cold pool associated with a digging short wave trough across southern Ontario into the lee of Lakes Ontario and Erie. However, with diurnal cooling underway and low-level cold advection ongoing to the lee of the lower Great Lakes, forecast soundings suggest that this activity is unlikely to persist beyond another hour or so. ..Kerr.. 11/12/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0647 PM CST Mon Nov 11 2024 Valid 120100Z - 121200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible through tonight. ...01Z Update... ...Pacific Coast... A mid-level tongue of cold air (including 500 mb temperatures of -24 to -28C) continues to migrate inland of the Pacific coast. It appears that the axis of coldest air is in the process of shifting to the east of the Sierra Nevada and Cascades. However, latest model output suggests that the mid-level temperatures may remain cold enough to support instability sufficient for a continuing risk of occasional weak convection capable of producing lightning, mainly to the west of the Cascades, through about 06-08Z. ...Lower Great Lakes... Occasional lightning flashes have been evident with convection developing beneath a lower/mid-level cold pool associated with a digging short wave trough across southern Ontario into the lee of Lakes Ontario and Erie. However, with diurnal cooling underway and low-level cold advection ongoing to the lee of the lower Great Lakes, forecast soundings suggest that this activity is unlikely to persist beyond another hour or so. ..Kerr.. 11/12/2024 Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0333 PM CST Mon Nov 11 2024 Valid 131200Z - 191200Z A progressive pattern will continue over the CONUS through the week but will likely become more amplified next weekend with upper-level troughs over/near both coasts. Multiple cold frontal passages will push south and east over both coasts, with little to no rain expected in portions of the broader southwest US, south/west Texas, and East Coast. ...Northeast and Mid-Atlantic... Multiple periods of breezy/gusty north-northwest flow is expected across the Northeast and Mid-Atlantic during the outlook period. Dry post-frontal conditions amid offshore flow will lead to elevated to locally critical fire weather conditions on Day 3/Wednesday, Day 5/Friday, and Day 6/Saturday. While it did rain yesterday, most areas received less than 0.25", including some areas less than 0.10", and record high fire danger persists. Given the forecast dry/breezy conditions and likely rain free area overlapping from far eastern PA and southern NJ extending northeast through southern New England, 40% areas were added. ...Southern/Central California... Gusty northerly/offshore flow remains possible in portions central/southern California this weekend, but forecast guidance is uncertain on the timing and magnitude. Additionally, forecast guidance has trended towards higher precipitation amounts and expanding precipitation farther south in California ahead of potential northerly/offshore flow, which would help mitigate fire weather concerns. ..Nauslar.. 11/11/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Mon Nov 11 20:42:02 UTC 2024.

No Mesoscale Discussions are in effect as of Mon Nov 11 20:42:02 UTC 2024.

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0123 PM CST Mon Nov 11 2024 Valid 112000Z - 121200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms appear unlikely through tonight. ...20z Update... No forecast changes are required, and the previous forecast (outlined below) remains on track. ..Moore.. 11/11/2024 .PREV DISCUSSION... /ISSUED 1035 AM CST Mon Nov 11 2024/ ...Discussion... A progressive large-scale regime will persist with troughing prevalent over the West and Great Lakes to Northeast, with upper ridging over the Great Plains. Over the middle Gulf Coast, isolated to widely scattered, episodic thunderstorms will be possible near an inverted trough and convergence zone in low levels, extending northeastward from the weakening, post-tropical remains of Rafael. A few strong storms may occur near coastal southeast Louisiana, but near-land severe potential should remain limited. Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0122 PM CST Mon Nov 11 2024 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER MISSISSIPPI VALLEY/CENTRAL GULF COAST REGION... ...SUMMARY... A marginal tornado/wind threat is apparent on Wednesday afternoon into Wednesday night across a part of the central Gulf Coast States. ...Synopsis... Some deamplification of the upper pattern over the U.S. is expected Wednesday, as a central U.S. trough advances eastward across the Plains through the day, and then into the Upper Great Lakes/Midwest/Tennessee Valley area overnight. As this occurs, a weakening surface cold front will likewise cross central portions of the country, extending from the Midwest to the central Gulf Coast area by the end of the period. ...Lower Mississippi Valley area... Rich low-level Gulf moisture is forecast to linger over the Lower Mississippi Valley/central Gulf Coast area Wednesday, ahead of the advancing cold front. Weak lapse rates aloft will limit surface-based instability, and meanwhile stronger flow aloft will remain farther north -- across the Mid Mississippi/Tennessee/Ohio Valleys. Still, slightly enhanced low-level flow is expected -- in part related to remnants of Rafael. The veering/increasing low-level winds with height may support transient rotation in a few of the longer-lived updrafts, and thus low-probability potential for a brief/weak tornado or two, or a strong wind gust, remains evident. ..Goss.. 11/11/2024 Read more