Severe Storms

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0649 AM CST Sat Feb 17 2024 Valid 171300Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the continental U.S. through tonight. ...Synopsis/Discussion... Mid/upper-level mean troughing will persist over eastern North America and the northeastern Pacific, with ridging across western portions of the CONUS and Canada. A vast cyclonic gyre anchors the Pacific mean trough. A notable shortwave perturbation -- evident in the broader cyclone's southeastern quadrant west of CA, near 135W -- will eject northeastward today, reaching the northwestern CA coastline around 06Z. Associated midlevel DCVA and steepening of low/middle-level lapse rates, will support weak buoyancy atop a cool, moist marine layer. Associated potential for widely scattered to scattered showers and isolated thunder will approach the coast during mid/late afternoon and persist until the trough passes late this evening. East of the ridge, another shortwave trough was evident in moisture- channel imagery across portions of CO/UT. This feature will shift southeastward to the Mid-South, Arklatex and North TX by the end of the period, causing height falls over the lower Mississippi Valley and western Gulf Coast regions. In response to these developments, a southern-stream trough now over west-central/north-central MX will move eastward across the western/northern parts of the MX Gulf Coast to the western Gulf. Several lesser vorticity lobes/shortwaves will travel downstream to FL, perhaps cooling initially unfavorably warm midlevel temperatures enough to contribute to isolated thunder potential within an extensive precip plume. The convection should be mainly along and north of a slow-moving cold front now located over central FL. Weak lows may traverse the front in association with the perturbations aloft, but the most prominent surface low preceding the main Mexican trough should remain west of the peninsula through the period. The front should move slowly southward, reaching south FL by 12Z tomorrow. Weak instability (especially in midlevels) and disorganized convective modes should preclude both a severe threat and more than isolated thunderstorms. ..Edwards/Mosier.. 02/17/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CST Sat Feb 17 2024 Valid 201200Z - 251200Z ...DISCUSSION... Medium-range model guidance shows an eastward progression of a lower-latitude mid-level trough to the east of the Southeast Atlantic coastal states early in the extended period. A mid-level ridge is forecast to shift east across the central U.S. by mid week with a vigorous upstream mid-level disturbance. Models differ on the evolution of this shortwave trough as it moves east into the MS Valley and eastern U.S. during the Thursday-Friday period. As a result, predictability of both moisture-return quality and important mass features is uncertain at this time. Nonetheless, some potential for severe thunderstorms may focus over parts of the lower MS Valley and Southeast U.S. late in the work week next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CST Sat Feb 17 2024 Valid 201200Z - 251200Z ...DISCUSSION... Medium-range model guidance shows an eastward progression of a lower-latitude mid-level trough to the east of the Southeast Atlantic coastal states early in the extended period. A mid-level ridge is forecast to shift east across the central U.S. by mid week with a vigorous upstream mid-level disturbance. Models differ on the evolution of this shortwave trough as it moves east into the MS Valley and eastern U.S. during the Thursday-Friday period. As a result, predictability of both moisture-return quality and important mass features is uncertain at this time. Nonetheless, some potential for severe thunderstorms may focus over parts of the lower MS Valley and Southeast U.S. late in the work week next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CST Sat Feb 17 2024 Valid 201200Z - 251200Z ...DISCUSSION... Medium-range model guidance shows an eastward progression of a lower-latitude mid-level trough to the east of the Southeast Atlantic coastal states early in the extended period. A mid-level ridge is forecast to shift east across the central U.S. by mid week with a vigorous upstream mid-level disturbance. Models differ on the evolution of this shortwave trough as it moves east into the MS Valley and eastern U.S. during the Thursday-Friday period. As a result, predictability of both moisture-return quality and important mass features is uncertain at this time. Nonetheless, some potential for severe thunderstorms may focus over parts of the lower MS Valley and Southeast U.S. late in the work week next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CST Sat Feb 17 2024 Valid 201200Z - 251200Z ...DISCUSSION... Medium-range model guidance shows an eastward progression of a lower-latitude mid-level trough to the east of the Southeast Atlantic coastal states early in the extended period. A mid-level ridge is forecast to shift east across the central U.S. by mid week with a vigorous upstream mid-level disturbance. Models differ on the evolution of this shortwave trough as it moves east into the MS Valley and eastern U.S. during the Thursday-Friday period. As a result, predictability of both moisture-return quality and important mass features is uncertain at this time. Nonetheless, some potential for severe thunderstorms may focus over parts of the lower MS Valley and Southeast U.S. late in the work week next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CST Sat Feb 17 2024 Valid 201200Z - 251200Z ...DISCUSSION... Medium-range model guidance shows an eastward progression of a lower-latitude mid-level trough to the east of the Southeast Atlantic coastal states early in the extended period. A mid-level ridge is forecast to shift east across the central U.S. by mid week with a vigorous upstream mid-level disturbance. Models differ on the evolution of this shortwave trough as it moves east into the MS Valley and eastern U.S. during the Thursday-Friday period. As a result, predictability of both moisture-return quality and important mass features is uncertain at this time. Nonetheless, some potential for severe thunderstorms may focus over parts of the lower MS Valley and Southeast U.S. late in the work week next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CST Sat Feb 17 2024 Valid 201200Z - 251200Z ...DISCUSSION... Medium-range model guidance shows an eastward progression of a lower-latitude mid-level trough to the east of the Southeast Atlantic coastal states early in the extended period. A mid-level ridge is forecast to shift east across the central U.S. by mid week with a vigorous upstream mid-level disturbance. Models differ on the evolution of this shortwave trough as it moves east into the MS Valley and eastern U.S. during the Thursday-Friday period. As a result, predictability of both moisture-return quality and important mass features is uncertain at this time. Nonetheless, some potential for severe thunderstorms may focus over parts of the lower MS Valley and Southeast U.S. late in the work week next week. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 AM CST Sat Feb 17 2024 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR A PORTION OF THE CENTRAL VALLEY OF CALIFORNIA... ...SUMMARY... An isolated risk for severe thunderstorms may develop across the Central Valley of California on Monday. ...Central valleys of CA... A mid- to upper-level low situated over the eastern Pacific to the west of northern CA/OR will move little during the period. A belt of strong southwesterly flow will extend from the eastern Pacific east-northeast to Sierra Nevada in association with a 160-kt 250-mb jet. Episodic showers and thunderstorms are forecast to move across central/northern CA during the period. Slight mid-level cooling is forecast over central/northern CA during the day with 500-mb temperatures decreasing into the -24 to -26 deg C range by late afternoon. Considerable cloud cover will inhibit appreciable heating, but forecast high temperatures (slightly warmer than the 17/00z NAM guidance) into the upper 50s to lower-mid 60s will result in weak destabilization. Veering and strengthening flow with height in the lowest 5-6 km will favor organized storm structures contingent on adequately strong/sustained updraft development. Current thinking is a couple of stronger updrafts may develop during peak heating and mature into shallow/transient supercell structures. A localized risk for a brief tornado and/or wind damage is possible. Elsewhere, tranquil conditions will exist across a large part of the CONUS from the Desert Southwest to the East Coast. ..Smith.. 02/17/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 AM CST Sat Feb 17 2024 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR A PORTION OF THE CENTRAL VALLEY OF CALIFORNIA... ...SUMMARY... An isolated risk for severe thunderstorms may develop across the Central Valley of California on Monday. ...Central valleys of CA... A mid- to upper-level low situated over the eastern Pacific to the west of northern CA/OR will move little during the period. A belt of strong southwesterly flow will extend from the eastern Pacific east-northeast to Sierra Nevada in association with a 160-kt 250-mb jet. Episodic showers and thunderstorms are forecast to move across central/northern CA during the period. Slight mid-level cooling is forecast over central/northern CA during the day with 500-mb temperatures decreasing into the -24 to -26 deg C range by late afternoon. Considerable cloud cover will inhibit appreciable heating, but forecast high temperatures (slightly warmer than the 17/00z NAM guidance) into the upper 50s to lower-mid 60s will result in weak destabilization. Veering and strengthening flow with height in the lowest 5-6 km will favor organized storm structures contingent on adequately strong/sustained updraft development. Current thinking is a couple of stronger updrafts may develop during peak heating and mature into shallow/transient supercell structures. A localized risk for a brief tornado and/or wind damage is possible. Elsewhere, tranquil conditions will exist across a large part of the CONUS from the Desert Southwest to the East Coast. ..Smith.. 02/17/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 AM CST Sat Feb 17 2024 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR A PORTION OF THE CENTRAL VALLEY OF CALIFORNIA... ...SUMMARY... An isolated risk for severe thunderstorms may develop across the Central Valley of California on Monday. ...Central valleys of CA... A mid- to upper-level low situated over the eastern Pacific to the west of northern CA/OR will move little during the period. A belt of strong southwesterly flow will extend from the eastern Pacific east-northeast to Sierra Nevada in association with a 160-kt 250-mb jet. Episodic showers and thunderstorms are forecast to move across central/northern CA during the period. Slight mid-level cooling is forecast over central/northern CA during the day with 500-mb temperatures decreasing into the -24 to -26 deg C range by late afternoon. Considerable cloud cover will inhibit appreciable heating, but forecast high temperatures (slightly warmer than the 17/00z NAM guidance) into the upper 50s to lower-mid 60s will result in weak destabilization. Veering and strengthening flow with height in the lowest 5-6 km will favor organized storm structures contingent on adequately strong/sustained updraft development. Current thinking is a couple of stronger updrafts may develop during peak heating and mature into shallow/transient supercell structures. A localized risk for a brief tornado and/or wind damage is possible. Elsewhere, tranquil conditions will exist across a large part of the CONUS from the Desert Southwest to the East Coast. ..Smith.. 02/17/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 AM CST Sat Feb 17 2024 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR A PORTION OF THE CENTRAL VALLEY OF CALIFORNIA... ...SUMMARY... An isolated risk for severe thunderstorms may develop across the Central Valley of California on Monday. ...Central valleys of CA... A mid- to upper-level low situated over the eastern Pacific to the west of northern CA/OR will move little during the period. A belt of strong southwesterly flow will extend from the eastern Pacific east-northeast to Sierra Nevada in association with a 160-kt 250-mb jet. Episodic showers and thunderstorms are forecast to move across central/northern CA during the period. Slight mid-level cooling is forecast over central/northern CA during the day with 500-mb temperatures decreasing into the -24 to -26 deg C range by late afternoon. Considerable cloud cover will inhibit appreciable heating, but forecast high temperatures (slightly warmer than the 17/00z NAM guidance) into the upper 50s to lower-mid 60s will result in weak destabilization. Veering and strengthening flow with height in the lowest 5-6 km will favor organized storm structures contingent on adequately strong/sustained updraft development. Current thinking is a couple of stronger updrafts may develop during peak heating and mature into shallow/transient supercell structures. A localized risk for a brief tornado and/or wind damage is possible. Elsewhere, tranquil conditions will exist across a large part of the CONUS from the Desert Southwest to the East Coast. ..Smith.. 02/17/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 AM CST Sat Feb 17 2024 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR A PORTION OF THE CENTRAL VALLEY OF CALIFORNIA... ...SUMMARY... An isolated risk for severe thunderstorms may develop across the Central Valley of California on Monday. ...Central valleys of CA... A mid- to upper-level low situated over the eastern Pacific to the west of northern CA/OR will move little during the period. A belt of strong southwesterly flow will extend from the eastern Pacific east-northeast to Sierra Nevada in association with a 160-kt 250-mb jet. Episodic showers and thunderstorms are forecast to move across central/northern CA during the period. Slight mid-level cooling is forecast over central/northern CA during the day with 500-mb temperatures decreasing into the -24 to -26 deg C range by late afternoon. Considerable cloud cover will inhibit appreciable heating, but forecast high temperatures (slightly warmer than the 17/00z NAM guidance) into the upper 50s to lower-mid 60s will result in weak destabilization. Veering and strengthening flow with height in the lowest 5-6 km will favor organized storm structures contingent on adequately strong/sustained updraft development. Current thinking is a couple of stronger updrafts may develop during peak heating and mature into shallow/transient supercell structures. A localized risk for a brief tornado and/or wind damage is possible. Elsewhere, tranquil conditions will exist across a large part of the CONUS from the Desert Southwest to the East Coast. ..Smith.. 02/17/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0225 AM CST Sat Feb 17 2024 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR A PORTION OF THE CENTRAL VALLEY OF CALIFORNIA... ...SUMMARY... An isolated risk for severe thunderstorms may develop across the Central Valley of California on Monday. ...Central valleys of CA... A mid- to upper-level low situated over the eastern Pacific to the west of northern CA/OR will move little during the period. A belt of strong southwesterly flow will extend from the eastern Pacific east-northeast to Sierra Nevada in association with a 160-kt 250-mb jet. Episodic showers and thunderstorms are forecast to move across central/northern CA during the period. Slight mid-level cooling is forecast over central/northern CA during the day with 500-mb temperatures decreasing into the -24 to -26 deg C range by late afternoon. Considerable cloud cover will inhibit appreciable heating, but forecast high temperatures (slightly warmer than the 17/00z NAM guidance) into the upper 50s to lower-mid 60s will result in weak destabilization. Veering and strengthening flow with height in the lowest 5-6 km will favor organized storm structures contingent on adequately strong/sustained updraft development. Current thinking is a couple of stronger updrafts may develop during peak heating and mature into shallow/transient supercell structures. A localized risk for a brief tornado and/or wind damage is possible. Elsewhere, tranquil conditions will exist across a large part of the CONUS from the Desert Southwest to the East Coast. ..Smith.. 02/17/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0112 AM CST Sat Feb 17 2024 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... Limited fire weather concerns are expected for Sunday across the country. Short and medium-range guidance show reasonably good agreement in depicting the gradual breakdown of the upper-level ridge observed over the Pacific Northwest through the next 48 hours. As this occurs, zonal flow over the central/northern Rockies will strengthen, resulting in lee troughing from eastern WY southward into the southern High Plains. Consequently, westerly downslope winds are forecast to increase through the day to around 15-20 mph, resulting in RH reductions into the 20-35% range. Some high-res solutions suggest that areas of elevated fire weather conditions are possible in the immediate lee of the northern/central Rockies from east-central WY to eastern NM. However, confidence in the coverage/duration of such conditions - including favorable overlap with sufficiently dry fuels - remains low, owing to spread in diurnal RH minimum forecasts and poor fuel status. ..Moore.. 02/17/2024 ...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 0112 AM CST Sat Feb 17 2024 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... Limited fire weather concerns are expected for Sunday across the country. Short and medium-range guidance show reasonably good agreement in depicting the gradual breakdown of the upper-level ridge observed over the Pacific Northwest through the next 48 hours. As this occurs, zonal flow over the central/northern Rockies will strengthen, resulting in lee troughing from eastern WY southward into the southern High Plains. Consequently, westerly downslope winds are forecast to increase through the day to around 15-20 mph, resulting in RH reductions into the 20-35% range. Some high-res solutions suggest that areas of elevated fire weather conditions are possible in the immediate lee of the northern/central Rockies from east-central WY to eastern NM. However, confidence in the coverage/duration of such conditions - including favorable overlap with sufficiently dry fuels - remains low, owing to spread in diurnal RH minimum forecasts and poor fuel status. ..Moore.. 02/17/2024 ...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 0112 AM CST Sat Feb 17 2024 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... Limited fire weather concerns are expected for Sunday across the country. Short and medium-range guidance show reasonably good agreement in depicting the gradual breakdown of the upper-level ridge observed over the Pacific Northwest through the next 48 hours. As this occurs, zonal flow over the central/northern Rockies will strengthen, resulting in lee troughing from eastern WY southward into the southern High Plains. Consequently, westerly downslope winds are forecast to increase through the day to around 15-20 mph, resulting in RH reductions into the 20-35% range. Some high-res solutions suggest that areas of elevated fire weather conditions are possible in the immediate lee of the northern/central Rockies from east-central WY to eastern NM. However, confidence in the coverage/duration of such conditions - including favorable overlap with sufficiently dry fuels - remains low, owing to spread in diurnal RH minimum forecasts and poor fuel status. ..Moore.. 02/17/2024 ...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 0112 AM CST Sat Feb 17 2024 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... Limited fire weather concerns are expected for Sunday across the country. Short and medium-range guidance show reasonably good agreement in depicting the gradual breakdown of the upper-level ridge observed over the Pacific Northwest through the next 48 hours. As this occurs, zonal flow over the central/northern Rockies will strengthen, resulting in lee troughing from eastern WY southward into the southern High Plains. Consequently, westerly downslope winds are forecast to increase through the day to around 15-20 mph, resulting in RH reductions into the 20-35% range. Some high-res solutions suggest that areas of elevated fire weather conditions are possible in the immediate lee of the northern/central Rockies from east-central WY to eastern NM. However, confidence in the coverage/duration of such conditions - including favorable overlap with sufficiently dry fuels - remains low, owing to spread in diurnal RH minimum forecasts and poor fuel status. ..Moore.. 02/17/2024 ...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 0112 AM CST Sat Feb 17 2024 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... Limited fire weather concerns are expected for Sunday across the country. Short and medium-range guidance show reasonably good agreement in depicting the gradual breakdown of the upper-level ridge observed over the Pacific Northwest through the next 48 hours. As this occurs, zonal flow over the central/northern Rockies will strengthen, resulting in lee troughing from eastern WY southward into the southern High Plains. Consequently, westerly downslope winds are forecast to increase through the day to around 15-20 mph, resulting in RH reductions into the 20-35% range. Some high-res solutions suggest that areas of elevated fire weather conditions are possible in the immediate lee of the northern/central Rockies from east-central WY to eastern NM. However, confidence in the coverage/duration of such conditions - including favorable overlap with sufficiently dry fuels - remains low, owing to spread in diurnal RH minimum forecasts and poor fuel status. ..Moore.. 02/17/2024 ...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 0112 AM CST Sat Feb 17 2024 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... Limited fire weather concerns are expected for Sunday across the country. Short and medium-range guidance show reasonably good agreement in depicting the gradual breakdown of the upper-level ridge observed over the Pacific Northwest through the next 48 hours. As this occurs, zonal flow over the central/northern Rockies will strengthen, resulting in lee troughing from eastern WY southward into the southern High Plains. Consequently, westerly downslope winds are forecast to increase through the day to around 15-20 mph, resulting in RH reductions into the 20-35% range. Some high-res solutions suggest that areas of elevated fire weather conditions are possible in the immediate lee of the northern/central Rockies from east-central WY to eastern NM. However, confidence in the coverage/duration of such conditions - including favorable overlap with sufficiently dry fuels - remains low, owing to spread in diurnal RH minimum forecasts and poor fuel status. ..Moore.. 02/17/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 0149 CONCERNING HEAVY SNOW FOR NORTHEAST WEST VIRGINIA TO WESTERN NEW JERSEY
Mesoscale Discussion 0149 NWS Storm Prediction Center Norman OK 0933 PM CST Fri Feb 16 2024 Areas affected...Northeast West Virginia to western New Jersey Concerning...Heavy snow Valid 170333Z - 170730Z SUMMARY...A swath of moderate to heavy snowfall will continue to spread east across parts of the Mid-Atlantic over the next several hours. DISCUSSION...A swath of moderate snowfall continues to spread east from the upper OH River Valley region into the Mid-Atlantic based on recent regional reflectivity composites. Transient organized snow bands continue to be observed within this broader zone, resulting in visibility reductions from 1/2 to 1/4 mile and steady snowfall accumulations based on recent snow reports from the region. Favorable phasing of synoptic ascent ahead of the approaching shortwave trough and strong isentropic and frontogenetic lift within the 925-700 mb layer, which has been driving this activity so far, is expected to persist as the system pushes towards the East Coast over the next several hours. Latest forecast guidance depicts reasonably high probability in snowfall rates between 1-2 inch/hour across portions of the Mid-Atlantic region (and possibly as far east as the NJ coast) through 08 UTC. Based on observed trends, this depiction seems fairly reasonable. One caveat is a lingering warm/dry layer below 850 mb sampled by regional 00 UTC soundings and noted in surface observations across northern MD, southeast PA, and into western NJ, which may limit snowfall rates in the near term. However, a combination of evaporative cooling and persistent mesoscale ascent along the warm frontal zone should support adequate low-level saturation/cooling to allow for moderate to heavy snowfall in the coming hours. ..Moore.. 02/17/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PHI...BGM...CTP...LWX...PBZ...RLX... LAT...LON 39027964 39317946 40797816 40987781 41047727 41097559 41007515 40867482 40557450 40117448 39847474 39707510 39607581 39587636 39537690 39397762 39217805 38927844 38757868 38677897 38687925 38787956 39027964 Read more