Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CST Thu Nov 21 2024 Valid 241200Z - 291200Z ...DISCUSSION... Models indicate a relatively strong zonal pattern over much of the CONUS for Sun/D4 into Mon/D5, with a shortwave trough skirting the Great Lakes area. Then, through the Thu/D8 period, there is a possibility of a low-amplitude trough amplification within this strong belt of flow, moving across the southern Plains and Southeast. Predictability for this later scenario is low at this time, as there is little run-to-run consistency. However, the air mass over the western Gulf of Mexico, spreading into the lower MS Valley, will become progressively more moist and unstable each day, and severe weather may become possible in those areas. The initial more robust moisture return from southeast TX across LA and southern MS/AL may be accompanied by substantial clouds and precipitation, but stronger destabilization will be possible as the warm front potentially moves north into the Wed/D7 to Thu/D8 time frame. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0148 AM CST Thu Nov 21 2024 Valid 231200Z - 241200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms appear unlikely across the USA on Saturday. ...Synopsis... A temporary/weakening upper ridge will exist over the Plains, with a departing trough over the Northeast and a broad region of west/southwest flow aloft over the West. By 12Z Sunday, this ridge will all but disappear due in part to an upper wave from MT into ND, and continued height falls across the West. The beginnings of moisture return will develop over TX in response to lower pressure over the Plains, with 50s F dewpoints primarily away from coast. Little if any instability is forecast across the entire CONUS through the period, and as such thunderstorms are not expected. ..Jewell.. 11/21/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1212 AM CST Thu Nov 21 2024 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms are possible along the Pacific Northwest Coast on Friday. ...Synopsis... A large, deep upper low will exist over the northeast Friday morning, and will gradually weaken as it drifts east through the period. Meanwhile, an upper ridge will slowly shift east from the Rockies into the Plains, while yet another trough pushes across the Pacific Northwest region late. Substantial northwest surface winds will maintain relatively stable conditions from the Plains to the East Coast, with no instability forecast over much of the CONUS. The exception will be again along the coastal counties of WA and OR, as strong cooling aloft occurs. Scattered low-topped convection will be most likely over the ocean overnight. A few thunderstorms may move onshore, but at this time the stronger shear farther north does not appear to overlap with the minimal instability required for a severe threat. ..Jewell.. 11/21/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1212 AM CST Thu Nov 21 2024 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms are possible along the Pacific Northwest Coast on Friday. ...Synopsis... A large, deep upper low will exist over the northeast Friday morning, and will gradually weaken as it drifts east through the period. Meanwhile, an upper ridge will slowly shift east from the Rockies into the Plains, while yet another trough pushes across the Pacific Northwest region late. Substantial northwest surface winds will maintain relatively stable conditions from the Plains to the East Coast, with no instability forecast over much of the CONUS. The exception will be again along the coastal counties of WA and OR, as strong cooling aloft occurs. Scattered low-topped convection will be most likely over the ocean overnight. A few thunderstorms may move onshore, but at this time the stronger shear farther north does not appear to overlap with the minimal instability required for a severe threat. ..Jewell.. 11/21/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1151 PM CST Wed Nov 20 2024 Valid 221200Z - 231200Z ...NO CRITICAL AREAS... ...Synopsis... A similar upper-level pattern to Thursday will again be present on Friday. The strong upper low will continue east and a complex surface low evolution will occur off the Mid-Atlantic/New England coast. Fire weather conditions are expected to be minimal for most areas. Northern into central Florida will again be dry. Temperature will be a bit cooler and RH will be a bit higher. Boundary layer mixing will also be less than Thursday, tempering gust potential. With the strongest winds/lowest RH expected over less receptive fuels, highlights will be withheld. Locally elevated conditions can be expected. ..Wendt.. 11/21/2024 ...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 1150 PM CST Wed Nov 20 2024 Valid 211200Z - 221200Z ...Synopsis... With a strong upper low over the lower Great Lakes region, strong flow aloft will overspread portions of the Southeast into Florida. A deepening low east of the DelMarVa will promote enhanced surface wind behind the cold front. With minimal precipitation falling over North Florida, where fuels are quite dry for this time of year, a period of elevated fire weather is expected. Winds of 10-15 mph and RH perhaps near 20% in some spots can be expected by the afternoon. The boundary layer should also deepen sufficiently to support gusts of up to 20 mph. ..Wendt.. 11/21/2024 ...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 1118 PM CST Wed Nov 20 2024 Valid 211200Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms are possible across southern New England Thursday morning. ...Southern New England... Strong upper low will shift southeast from the Great Lakes into the upper Ohio Valley by late afternoon. This evolution will encourage low-level warm advection across southern New England as a surface low repositions itself off the middle Atlantic coast, south of Long Island. Forecast soundings suggest weak elevated buoyancy will develop north of this boundary as mid-level lapse rates will steepen as 500mb temperatures cool in advance of the approaching trough. Strongest elevated updrafts may exceed levels necessary for lightning discharge, but this should mainly be prior to 18z. Thereafter, deepest convection will focus offshore. ..Darrow/Wendt.. 11/21/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0640 PM CST Wed Nov 20 2024 Valid 210100Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected tonight; although, a few strong storms may be noted along the immediate Washington/Oregon Coast this evening. ...01z Update... Strong upper low off the BC/WA coast should gradually fill tonight as it occludes offshore. As a result, mid-level heights will gradually rise through sunrise, and onshore flow should weaken. Until then, a few longer-lived showers/supercells developed about 100mi offshore and are now moving inland, especially over northwest Pacific County WA. This convection was aided by marine-influenced buoyancy, but this activity will quickly weaken as it encounters a poor air mass inland. Some near-term risk for gusty winds, and perhaps an offshore water spout, exist for the next few hours. However, severe threat does not appear to be enough to warrant severe probabilities overnight. Downstream across the middle Atlantic, strong height falls will spread across this region (180m in 12hr) ahead of a pronounced upper low shifting southeast across the Great Lakes. A plume of modest 0-3km lapse rates developed across the Ohio Valley earlier this afternoon which appeared to aid shallow convection across eastern OH into western PA, where some localized damaging winds were noted. However, this convection has spread well east of this steeper plume and poor low-level lapse rates downstream do not support robust updrafts overnight. ..Darrow.. 11/21/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0640 PM CST Wed Nov 20 2024 Valid 210100Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected tonight; although, a few strong storms may be noted along the immediate Washington/Oregon Coast this evening. ...01z Update... Strong upper low off the BC/WA coast should gradually fill tonight as it occludes offshore. As a result, mid-level heights will gradually rise through sunrise, and onshore flow should weaken. Until then, a few longer-lived showers/supercells developed about 100mi offshore and are now moving inland, especially over northwest Pacific County WA. This convection was aided by marine-influenced buoyancy, but this activity will quickly weaken as it encounters a poor air mass inland. Some near-term risk for gusty winds, and perhaps an offshore water spout, exist for the next few hours. However, severe threat does not appear to be enough to warrant severe probabilities overnight. Downstream across the middle Atlantic, strong height falls will spread across this region (180m in 12hr) ahead of a pronounced upper low shifting southeast across the Great Lakes. A plume of modest 0-3km lapse rates developed across the Ohio Valley earlier this afternoon which appeared to aid shallow convection across eastern OH into western PA, where some localized damaging winds were noted. However, this convection has spread well east of this steeper plume and poor low-level lapse rates downstream do not support robust updrafts overnight. ..Darrow.. 11/21/2024 Read more

No watches are valid as of Wed Nov 20 21:36:02 UTC 2024.

No Mesoscale Discussions are in effect as of Wed Nov 20 21:36:02 UTC 2024.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0257 PM CST Wed Nov 20 2024 Valid 221200Z - 281200Z Fire weather concerns remain limited through the extended period. Medium and long-range ensemble guidance continues to depict a synoptic regime unfavorable for widespread fire weather potential through at least early next week. The upper trough currently over the upper MS River valley is expected to gradually shift east over the next few days and will support somewhat widespread precipitation chances across the Great Lakes, Ohio River Valley, and Northeast. An amplification of the upper trough across the inter-mountain West and Plains through the weekend will promote dry, but relatively benign conditions across the Southwest/Rockies. The development of a lee cyclone along the northern High Plains on D4/Saturday may support a dry return flow regime across the southern Plains, but recent rainfall will likely limit fuel status. Ensemble cluster analyses suggest a breakdown of the upper ridge is likely by early next week with the potential for one or more upper waves migrating across the Southwest/southern High Plains during the D6/Monday to D8/Wednesday time period. While no strong signals are noted in recent ensemble and deterministic solutions, these waves could present opportunities for fire weather concerns across parts of the western Plains where little rainfall is expected through the middle of next week. ..Moore.. 11/20/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0257 PM CST Wed Nov 20 2024 Valid 221200Z - 281200Z Fire weather concerns remain limited through the extended period. Medium and long-range ensemble guidance continues to depict a synoptic regime unfavorable for widespread fire weather potential through at least early next week. The upper trough currently over the upper MS River valley is expected to gradually shift east over the next few days and will support somewhat widespread precipitation chances across the Great Lakes, Ohio River Valley, and Northeast. An amplification of the upper trough across the inter-mountain West and Plains through the weekend will promote dry, but relatively benign conditions across the Southwest/Rockies. The development of a lee cyclone along the northern High Plains on D4/Saturday may support a dry return flow regime across the southern Plains, but recent rainfall will likely limit fuel status. Ensemble cluster analyses suggest a breakdown of the upper ridge is likely by early next week with the potential for one or more upper waves migrating across the Southwest/southern High Plains during the D6/Monday to D8/Wednesday time period. While no strong signals are noted in recent ensemble and deterministic solutions, these waves could present opportunities for fire weather concerns across parts of the western Plains where little rainfall is expected through the middle of next week. ..Moore.. 11/20/2024 ...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 0150 PM CST Wed Nov 20 2024 Valid 202000Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms appear unlikely through tonight across the contiguous United States. ...20z Update... No changes are needed to the current D1 Convective Outlook. See previous discussion below for more information. ..Thornton/Smith.. 11/20/2024 .PREV DISCUSSION... /ISSUED 1030 AM CST Wed Nov 20 2024/ ...Mid-Atlantic into North Carolina... Midday water-vapor imagery shows a cyclone over the Upper Midwest that will move eastward across the Great Lakes through tonight. A cold front will advance eastward over these regions. While low-level moisture will gradually increase across NC into the southern Mid-Atlantic by early evening, considerable cloud cover and relatively meager lapse rates will only result in pockets of weak instability. Nonetheless, low-topped convection should still form along or just ahead of the cold front across eastern OH into western PA and WV by late this afternoon according to the latest guidance. 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 storm intensity. ...Coastal Pacific Northwest... A powerful upper cyclone west of British Columbia will occlude and gradually move away from the coast. Low-level warm advection will support intermittent low-topped convection across coastal portions of the Pacific Northwest. With surface dewpoints generally in the low to mid 40s over land, instability will remain scant---precluding a severe risk. Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0106 PM CST Wed Nov 20 2024 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated to scattered thunderstorms are possible along the Pacific Northwest Coast on Friday. ...Synopsis... A large upper low will start to move off the East Coast on Friday. In its wake, a dry/cool continental airmass will overspread the eastern CONUS which will result in no thunderstorm threat. ...Pacific Northwest Coast... Cooling air aloft across the northeast Pacific, associated with the approaching mid-level trough, will lead to enough instability over the water to support some thunderstorm activity. Some of these thunderstorms may impact coastal areas during the day on Friday. Very strong synoptic winds are likely along the coast as a sub-990mb low moves north along the coast. Thunderstorm activity could enhance some of these winds and lead to increased wind damage threat, but instability is too limited for a marginal risk at this time. ..Bentley.. 11/20/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1238 PM CST Wed Nov 20 2024 Valid 211200Z - 221200Z ...NO CRITICAL AREAS... The previous forecast remains on track with no changes needed. Portions of central to northern FL saw only light rainfall over the past 24 hours, per MRMS rainfall estimates. Fuels may remain somewhat receptive across this region, but confidence in sustained 15+ mph winds remains too limited for highlights. See the previous discussion below for additional details. ..Moore.. 11/20/2024 .PREV DISCUSSION... /ISSUED 1142 PM CST Tue Nov 19 2024/ ...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. ...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 1104 AM CST Wed Nov 20 2024 Valid 211200Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Thursday. ...Synopsis... A strong upper level low will rotate eastward across the eastern CONUS tomorrow. A surface low will deepen and eventually occlude into the interior Northeast during the afternoon/evening. Isentropic ascent will lead to some elevated instability and thunderstorm potential from the Mid-Atlantic to New England tomorrow morning and afternoon. Weak instability should mitigate any severe weather concerns. Cold air aloft will result in some weak instability across the northeast Pacific. Isolated thunderstorms will be possible along the Washington coast, primarily during the morning and early afternoon. ..Bentley.. 11/20/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1104 AM CST Wed Nov 20 2024 Valid 211200Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Thursday. ...Synopsis... A strong upper level low will rotate eastward across the eastern CONUS tomorrow. A surface low will deepen and eventually occlude into the interior Northeast during the afternoon/evening. Isentropic ascent will lead to some elevated instability and thunderstorm potential from the Mid-Atlantic to New England tomorrow morning and afternoon. Weak instability should mitigate any severe weather concerns. Cold air aloft will result in some weak instability across the northeast Pacific. Isolated thunderstorms will be possible along the Washington coast, primarily during the morning and early afternoon. ..Bentley.. 11/20/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1030 AM CST Wed Nov 20 2024 Valid 201630Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms appear unlikely through tonight across the contiguous United States. ...Mid-Atlantic into North Carolina... Midday water-vapor imagery shows a cyclone over the Upper Midwest that will move eastward across the Great Lakes through tonight. A cold front will advance eastward over these regions. While low-level moisture will gradually increase across NC into the southern Mid-Atlantic by early evening, considerable cloud cover and relatively meager lapse rates will only result in pockets of weak instability. Nonetheless, low-topped convection should still form along or just ahead of the cold front across eastern OH into western PA and WV by late this afternoon according to the latest guidance. 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 storm intensity. ...Coastal Pacific Northwest... A powerful upper cyclone west of British Columbia will occlude and gradually move away from the coast. Low-level warm advection will support intermittent low-topped convection across coastal portions of the Pacific Northwest. With surface dewpoints generally in the low to mid 40s over land, instability will remain scant---precluding a severe risk. ..Smith/Flournoy.. 11/20/2024 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1016 AM CST Wed Nov 20 2024 Valid 201700Z - 211200Z ...Central Plains... The previous forecast remains on track with only minor adjustments made based on recent observations and trends in forecast guidance. Gradient winds gusting to 40-50 mph are already being observed across southern SD and will spread into NE by late morning as a shallow nocturnal inversion (evident on the 12z LBF sounding) mixes out. The greatest fire threat should be focused across southwest SD into western NE where fuels are driest, but elevated to critical fire weather conditions will likely spread into south-central NE as well. However, recent 1+ inch rainfall amounts within the past 24 hours should limit fire potential with eastward extent. ...Western to central Nevada... Localized elevated to critical fire weather conditions are ongoing this morning across far western NV within the downslope wind regime in the lee of the central Sierra Nevada. Such conditions should gradually become more widespread into central NV by late afternoon as diurnal heating promotes drying/mixing. Despite the wind/RH conditions, recent fuel guidance suggests ERCs remain below critical thresholds to warrant risk highlights. ..Moore.. 11/20/2024 .PREV DISCUSSION... /ISSUED 1141 PM CST Tue Nov 19 2024/ ...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. ...Please see www.spc.noaa.gov/fire for graphic product... Read more