SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0654 AM CST Wed Nov 20 2024 Valid 201300Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely today and tonight. ...Mid-Atlantic into North Carolina... An occluded cyclone over the Upper Midwest this morning will evolve eastward across the Great Lakes through tonight. A related strong mid/upper-level jet will overspread the OH Valley into the Mid-Atlantic and Carolinas through the day, as a surface cold front also advances eastward over these regions. While low-level moisture will gradually increase across NC into the southern Mid-Atlantic by early evening, poor lapse rates and limited daytime heating should hinder the development of any more than weak instability. Still, low-topped showers should still form along or just ahead of the cold front across eastern OH into western PA and WV by late this afternoon. It remains unclear whether this convection will become deep enough to foster lightning flashes, but enhanced low/mid-level flow could still support some chance for gusty winds with this activity. This elevated convection is forecast to continue moving eastward over the southern Mid-Atlantic this evening and overnight. However, boundary-layer instability is forecast to remain minimal with eastward extent, which should limit the overall severe threat. ...Coastal Pacific Northwest... A powerful upper cyclone off the coast of British Columbia should continue to occlude today as it moves slowly away from the coast. In the meantime, ascent associated with low-level warm advection and a strong southwesterly mid/upper-level jet is supporting low-topped convection this morning across coastal portions of the Pacific Northwest. With surface dewpoints generally in the low to mid 40s over land, instability will remain very limited (reference negligible MUCAPE from 12Z observed soundings at UIL/SLE). Still, some chance strong/gusty winds may exist with the ongoing convection moving onshore given the strength of the low/mid-level flow (see recent VWPs from KLGX). But, the scant instability should preclude organized severe thunderstorms across coastal WA/OR today. ...Florida... Convection over the eastern Gulf of Mexico has generally weakened as it approaches the FL Gulf Coast and Keys early this morning. The potential for appreciable destabilization over land today should remain limited ahead of a cold front. While isolated lighting flashes may still occur along/near the coast and parts of the Keys, better thunderstorm potential will probably remain offshore from the FL Peninsula. ..Gleason/Kerr.. 11/20/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0305 AM CST Wed Nov 20 2024 Valid 231200Z - 281200Z ...DISCUSSION... An upper trough will move out of the northeastern states from Sat/D4 into Sun/D5, with the ridge flattening over the Plains. This will result in a broad belt of near zonal flow across much of the CONUS, with perhaps a slight propensity for cyclonic height curvature over the Great Lakes into eastern Canada. Low-level moisture return will occur gradually, especially from Mon/D6 onward when 60s dewpoints may extend from eastern TX into the lower MS Valley. However, not until around Tue Night/D7 do most models show any appreciable instability, and even then it will likely be weak. As such, severe storms are not forecast. However, a few strong storms cannot be ruled out by around Wed/D8 due to several days of persistent moistening, especially if a shortwave trough can amplify within the strong flow regime. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0208 AM CST Wed Nov 20 2024 Valid 221200Z - 231200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorm activity will remain quite limited on Friday. ...Synopsis... A deep upper low will begin centered over the PA/NY area, but within a large, deep upper trough. Meanwhile, an upper ridge will exist over the Rockies, shifting slowly east toward the High Plains by 12Z Saturday. West of this ridge, height falls will occur over the Pacific Northwest as a broad upper trough moves in. High pressure will persist over much of the CONUS, the exception being over the Northeast near the deep tropospheric cyclone, with a dry air mass lacking of CAPE. The exception will be just off the WA/OR coasts, where low-topped convection is possible over the ocean, and perhaps near the coastline by 12Z Saturday. ..Jewell.. 11/20/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0208 AM CST Wed Nov 20 2024 Valid 221200Z - 231200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorm activity will remain quite limited on Friday. ...Synopsis... A deep upper low will begin centered over the PA/NY area, but within a large, deep upper trough. Meanwhile, an upper ridge will exist over the Rockies, shifting slowly east toward the High Plains by 12Z Saturday. West of this ridge, height falls will occur over the Pacific Northwest as a broad upper trough moves in. High pressure will persist over much of the CONUS, the exception being over the Northeast near the deep tropospheric cyclone, with a dry air mass lacking of CAPE. The exception will be just off the WA/OR coasts, where low-topped convection is possible over the ocean, and perhaps near the coastline by 12Z Saturday. ..Jewell.. 11/20/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1248 AM CST Wed Nov 20 2024 Valid 211200Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Thursday. ...Synopsis... A stable pattern in terms of thunderstorm potential will exist across the CONUS on Thursday, with a large upper cyclone over the eastern states and a ridge over the Rockies. High pressure will stretch from the Great Basin/Rockies across the Plains and into the Southeast, with a low over the Northeast. This will result in offshore flow across the Gulf of Mexico and western Atlantic, and maintain a relatively CAPE-free air mass over land. A very low change of sporadic lightning flashes may brush parts of southern New England as moisture and elevated theta-e wraps northwestward toward the surface low. However, this instability will be elevated in nature, with such low values suggesting less than 10% chance of lightning. ..Jewell.. 11/20/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1142 PM CST Tue Nov 19 2024 Valid 211200Z - 221200Z ...NO CRITICAL AREAS... ...Synopsis... For Thursday, a strong upper low over the Upper Midwest will shift into the Mid-Atlantic by Friday morning. The post-frontal airmass behind the cold front in the Southeast/Florida will lead to RH reductions by the afternoon across these areas. Generally light winds and preceding precipitation should limit most fire weather concerns. Depending on the amount of precipitation that falls on late Tuesday into early Wednesday, a modest increase in fire weather concerns could occur in parts of northern/central Florida which have seen little rainfall in the last week. Uncertainty remains too high for highlights, however. ..Wendt.. 11/20/2024 ...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 1141 PM CST Tue Nov 19 2024 Valid 201200Z - 211200Z ...Synopsis... An upper-level low initially in the northern Plains will shift eastward into the Upper Midwest and intensify today. Strong low to mid-level winds will continue across portions of the central Plains as an associated surface low deepens in the Lower Great Lakes region. ...Central Plains... Temperatures will again be rather cool (mid/upper 40s F appear most probable). However, strong surface winds of 15-25 mph (with higher gusts) are likely across parts of eastern Wyoming into adjacent South Dakota and western Nebraska. RH will also fall to near 20% given the very dry airmass. Some fire weather concern could develop in fine fuels. Some weakening of the pressure gradient is expected by late afternoon which will limit the duration of the threat. ..Wendt.. 11/20/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1058 PM CST Tue Nov 19 2024 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe weather is not expected Today. ...Discussion... An upper low initially over the north-central U.S. is forecast to shift southeastward across the Upper Great Lakes region with time, deepening through the second half of the period. Meanwhile, a second low is forecast to remain off the Pacific Northwest Coast. At the surface, an occluded low will shift across the Upper Great Lakes in tandem with the upper cyclone, while a cold front crosses the Appalachians through the first half of the period. Overnight, the front will move off the Middle and Southern Atlantic Coast, lingering only across southern portions of Florida by the end of the period Thursday morning. With a zone of strong onshore/upslope southwesterly flow across the Pacific Northwest southeast of the offshore upper low, showers and occasional lightning flashes will occur, with lightning potential focused near the Coast Ranges. Showers and embedded thunderstorms will also be possible across the Mid-Atlantic states south to North Carolina, ahead of the advancing surface cold front. Given weak/slightly elevated instability anticipated across this area, severe weather is not expected. Finally, showers and a few thunderstorms are forecast across portions of the Florida Peninsula, but with weak lapse rates and modest flow aloft, severe storms are not anticipated. ..Goss/Wendt.. 11/20/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1058 PM CST Tue Nov 19 2024 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe weather is not expected Today. ...Discussion... An upper low initially over the north-central U.S. is forecast to shift southeastward across the Upper Great Lakes region with time, deepening through the second half of the period. Meanwhile, a second low is forecast to remain off the Pacific Northwest Coast. At the surface, an occluded low will shift across the Upper Great Lakes in tandem with the upper cyclone, while a cold front crosses the Appalachians through the first half of the period. Overnight, the front will move off the Middle and Southern Atlantic Coast, lingering only across southern portions of Florida by the end of the period Thursday morning. With a zone of strong onshore/upslope southwesterly flow across the Pacific Northwest southeast of the offshore upper low, showers and occasional lightning flashes will occur, with lightning potential focused near the Coast Ranges. Showers and embedded thunderstorms will also be possible across the Mid-Atlantic states south to North Carolina, ahead of the advancing surface cold front. Given weak/slightly elevated instability anticipated across this area, severe weather is not expected. Finally, showers and a few thunderstorms are forecast across portions of the Florida Peninsula, but with weak lapse rates and modest flow aloft, severe storms are not anticipated. ..Goss/Wendt.. 11/20/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0657 PM CST Tue Nov 19 2024 Valid 200100Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm potential is expected to remain minimal through tonight. ...Discussion... An area of showers and thunderstorms is currently moving out of the central/into the eastern Gulf of Mexico, will all lightning currently relegated to offshore areas. Still, a few flashes will be possible overnight -- perhaps as far inland as the southern Appalachians. As the Gulf convection moves eastward, a stronger storm or two may affect the Florida Big Bend area, with gusty winds or even a waterspout near the coast not entirely out of the question. However, any severe potential appears far too low to warrant an areal outline. Otherwise, a few lightning flashes may move onshore across the Pacific Northwest later tonight, within a convective band moving eastward ahead of the strong/offshore upper low. Severe-weather potential appears negligible. ..Goss.. 11/20/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0657 PM CST Tue Nov 19 2024 Valid 200100Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm potential is expected to remain minimal through tonight. ...Discussion... An area of showers and thunderstorms is currently moving out of the central/into the eastern Gulf of Mexico, will all lightning currently relegated to offshore areas. Still, a few flashes will be possible overnight -- perhaps as far inland as the southern Appalachians. As the Gulf convection moves eastward, a stronger storm or two may affect the Florida Big Bend area, with gusty winds or even a waterspout near the coast not entirely out of the question. However, any severe potential appears far too low to warrant an areal outline. Otherwise, a few lightning flashes may move onshore across the Pacific Northwest later tonight, within a convective band moving eastward ahead of the strong/offshore upper low. Severe-weather potential appears negligible. ..Goss.. 11/20/2024 Read more

No watches are valid as of Tue Nov 19 22:32:01 UTC 2024.

No Mesoscale Discussions are in effect as of Tue Nov 19 22:32:01 UTC 2024.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0219 PM CST Tue Nov 19 2024 Valid 211200Z - 271200Z Fire weather concerns are expected to remain limited through early next week across the country. The upper trough currently in place across the central U.S. will gradually shift east through the remainder of the week with attendant rain chances overspreading much of the Great Lakes and New England regions. Upper ridging appears likely across the inter-mountain West/Plains in the wake of the eastern trough, which will promote dry conditions but relatively benign low-level gradient winds. Along the West Coast, the intensifying low off the Pacific Northwest coast will maintain widespread rain/snow chances through the end of the week before gradually de-amplifying and shifting inland. Most regions are expected to see some degree of precipitation by the weekend, which will mitigate fuel/fire concerns. The only exceptions to this will be the Four Corners and the southern to central Plains where the probability for wetting rainfall appears fairly low. Some fuel drying is anticipated across these regions, though recent heavy rain across the Plains will require multiple days of warm, dry, and windy conditions to support a fire concern. Long-range ensemble guidance hints that a breakdown of the upper ridge is likely by early next week, which may support dry/windy conditions across the Four Corners/southern Plains as shortwave troughs propagate eastward within the mean zonal flow regime. However, confidence in any fire concern is very low at this range. ..Moore.. 11/19/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0135 PM CST Tue Nov 19 2024 Valid 192000Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm potential is expected to remain low the remainder of the afternoon thought tonight. ...20z Update - Central Gulf Coast vicinity... Severe probabilities have been removed as inland convection has outpaced axis of modest instability. Any stronger storms are expected to remain offshore. ..Leitman.. 11/19/2024 .PREV DISCUSSION... /ISSUED 1021 AM CST Tue Nov 19 2024/ ...Middle Gulf Coast including southern AL/FL Panhandle... Severe-weather potential is expected to remain relatively limited today and largely relegated to near-coastal areas of southern Alabama and the Florida Panhandle. A longwave trough will remain centered across a broad part of the Midwest and Great Lakes, well to the north of a weak surface wave and a nearby narrow inland warm sector along the middle Gulf Coast. This warm/moist sector will largely focus offshore due to a lack of more appreciable cyclogenesis and persistent showers/thunderstorms inland. The southern extent of a persistent but weakening (25-40 kt) south-southwesterly low-level jet will migrate slowly eastward today across the Gulf Coast vicinity. A brief waterspout and/or tornado could occur with low-topped rotating cells along or very near the coast given adequate 0-1 km SRH and greater low-level moisture present (generally 70s F surface dewpoints). Otherwise, isolated damaging wind gusts may occur with convection moving eastward along or just ahead of the front. Meager instability should keep the severe potential rather isolated and marginal overall. Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0128 PM CST Tue Nov 19 2024 Valid 211200Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Thursday. ...Synopsis... A deep mid/upper-level low will move slowly east-southeastward from the Great Lakes into the Mid-Atlantic/southern New England through the period. Ahead of this feature and north of a related coastal surface low, cold temperatures aloft/modestly steep midlevel lapse rates will contribute to weak elevated instability over immediate coastal areas of southern New England during the morning hours. While an isolated lightning flash will be possible within a swath of warm-advection precipitation, the overall coverage appears too limited for a General Thunderstorm area. Elsewhere, expansive surface ridging over the western/central CONUS and related offshore flow will limit thunderstorm potential. ..Weinman.. 11/19/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0128 PM CST Tue Nov 19 2024 Valid 211200Z - 221200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Thursday. ...Synopsis... A deep mid/upper-level low will move slowly east-southeastward from the Great Lakes into the Mid-Atlantic/southern New England through the period. Ahead of this feature and north of a related coastal surface low, cold temperatures aloft/modestly steep midlevel lapse rates will contribute to weak elevated instability over immediate coastal areas of southern New England during the morning hours. While an isolated lightning flash will be possible within a swath of warm-advection precipitation, the overall coverage appears too limited for a General Thunderstorm area. Elsewhere, expansive surface ridging over the western/central CONUS and related offshore flow will limit thunderstorm potential. ..Weinman.. 11/19/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1223 PM CST Tue Nov 19 2024 Valid 201200Z - 211200Z The previous forecast remains on track with only minor adjustments needed based on latest high-res guidance. Similar conditions to today (Tuesday) remain likely Wednesday across the Plains and will support a wind-driven fire weather concern. For additional details see the previous discussion below. ..Moore.. 11/19/2024 .PREV DISCUSSION... /ISSUED 1240 AM CST Tue Nov 19 2024/ ...Synopsis... The strong upper trough in the central Plains will move east on Wednesday. A strong belt of northwesterly mid-level winds will remain over the Plains. A new surface low will then deepen in the Lower Great Lakes region. ...Central Plains... A similar setup to Tuesday will again occur on Wednesday across parts of Wyoming, South Dakota, and Nebraska. Temperatures will again remain quite cool, but the remaining dry airmass coupled with a modest downslope wind component will promote 20-30% RH by the afternoon. Winds will again be the primary driver of fire weather concern with 15-25 mph sustained winds being fairly common along with stronger gusts. The fire weather threat should begin to diminish by mid/late afternoon as the surface pressure gradient weakens. ...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 1223 PM CST Tue Nov 19 2024 Valid 201200Z - 211200Z The previous forecast remains on track with only minor adjustments needed based on latest high-res guidance. Similar conditions to today (Tuesday) remain likely Wednesday across the Plains and will support a wind-driven fire weather concern. For additional details see the previous discussion below. ..Moore.. 11/19/2024 .PREV DISCUSSION... /ISSUED 1240 AM CST Tue Nov 19 2024/ ...Synopsis... The strong upper trough in the central Plains will move east on Wednesday. A strong belt of northwesterly mid-level winds will remain over the Plains. A new surface low will then deepen in the Lower Great Lakes region. ...Central Plains... A similar setup to Tuesday will again occur on Wednesday across parts of Wyoming, South Dakota, and Nebraska. Temperatures will again remain quite cool, but the remaining dry airmass coupled with a modest downslope wind component will promote 20-30% RH by the afternoon. Winds will again be the primary driver of fire weather concern with 15-25 mph sustained winds being fairly common along with stronger gusts. The fire weather threat should begin to diminish by mid/late afternoon as the surface pressure gradient weakens. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1127 AM CST Tue Nov 19 2024 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe weather is not expected on Wednesday. Isolated thunderstorms are most likely over parts of Florida and the Carolinas, and along the coastal Pacific Northwest. ...Synopsis... A deep upper trough/low will evolve eastward from the Upper MS Valley into the Great Lakes through the period. In response, a surface low will deepen and gradually occlude over the Great Lakes, while a related cold front moves eastward across the eastern states. Strong midlevel height falls preceding the upper trough will promote scattered showers with isolated/embedded lightning along/ahead of the cold front. Despite strong deep-layer westerly flow/shear accompanying the trough, limited heating/poor lapse rates and dry air aloft should limit updraft intensity. Over the western FL Peninsula, richer boundary-layer moisture will be in place along/ahead of the front, where guidance indicates a weak frontal wave low during the morning. Here, strong low-level flow (and curved low-level hodographs) could favor a few strong/rotating storms approaching the coast, though weak instability/lapse rates should limit the severe threat over land. Farther west, several perturbations embedded in a belt of strong mid/upper-level westerly flow -- within the base of a midlevel low off the BC coast -- will promote isolated thunderstorms across the Pacific Northwest coast through the period. Elongated hodographs (with ample low-level curvature) will conditionally support a few strong/embedded cells capable of locally strong gusts and possibly waterspouts. However, any severe threat onshore appears too conditional for severe probabilities at this time. ..Weinman.. 11/19/2024 Read more