Severe Storms

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 AM CDT Sat Mar 23 2024 Valid 231300Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTH FLORIDA AND THE KEYS... ...SUMMARY... Isolated strong to severe thunderstorms may occur today across parts of south Florida and the Keys. ...Synopsis... In mid/upper levels, a series of shortwaves -- including the open- wave remnants of a cyclone now moving toward the Pacific Northwest Coast -- will contribute to development of a large synoptic trough over the West by 12Z tomorrow. Meanwhile, a downstream/southern- stream perturbation -- evident in moisture-channel imagery over the southern Appalachians to the FL Panhandle and central Gulf -- will shift eastward. By 00Z, the trough should extend from the Carolinas and coastal GA south-southwestward across northern FL and the extreme eastern Gulf. By 12Z, the trough should be offshore from the southern Atlantic Coast, including FL. At the surface, 11Z analysis showed a frontal-wave low over northeastern NC in the RDU/RWI area, with cold front across central portions of SC/GA to the west-central FL Panhandle and central Gulf. A prefrontal trough with northwesterly wind shift was drawn across southern GA, the FL coastal bend, and the east-central Gulf. A warm front -- poorly defined due to the presence of convection and dense precip on both sides -- was apparent from the low southeastward over parts of the Outer Banks. The low should move swiftly northeastward today, reaching near Montauk Point around 00Z, with the trailing cold front effectively catching the trough and moving offshore from the remainder of the Atlantic Coast (including FL). ...South FL/Keys... Widely scattered to scattered thunderstorms are possible through midafternoon in the destabilizing, prefrontal warm sector over south FL. The most vigorous cells may produce marginally severe gusts. The prefrontal air mass over the region will remain characterized by surface dewpoints around 68-72 F over most of south FL. Modified RAOBs and forecast soundings suggest this will support around 1000- 1500 J/kg MLCAPE with minimal CINH, and that convection now over parts of south FL already may be surface-based in the recovery zone of warm advection behind the prior night's activity. However, light and variable winds near the surface will become southwesterly to westerly through midday, while flow from just above the surface through 850 mb veers more. Though this will reduce hodograph size markedly, sufficient speed shear will remain to yield effective- shear magnitudes around 45-60 kt. Weak/intermittent supercell characteristics may be noted, while fast cell motions contribute to locally damaging downdrafts. ...Eastern NC... Somewhat organized thunderstorms extend from near HSE south- southwestward over Atlantic waters, moving northeastward. The most- intense activity should remain offshore where low-level instability and deep bulk shear each should be most favorable. Persistent overland precip has minimized buoyancy, and deep shear should continue to diminish as flow aloft weakens with time nearest the trough aloft. Behind the early precip area, some destabilization, related to both warm advection and patchy insolation, is expected diurnally. This may support isolated to widely scattered convection along/ahead of the cold front. However, with the low and associated isallobaric forcing moving quickly away from the region and up the Mid-Atlantic Coast through 18Z, warm-sector flow will veer, further reducing both vertical shear and low-level convergence. As such, unconditional potential appears too low to maintain a severe outlook. ..Edwards/Grams.. 03/23/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 AM CDT Sat Mar 23 2024 Valid 231300Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTH FLORIDA AND THE KEYS... ...SUMMARY... Isolated strong to severe thunderstorms may occur today across parts of south Florida and the Keys. ...Synopsis... In mid/upper levels, a series of shortwaves -- including the open- wave remnants of a cyclone now moving toward the Pacific Northwest Coast -- will contribute to development of a large synoptic trough over the West by 12Z tomorrow. Meanwhile, a downstream/southern- stream perturbation -- evident in moisture-channel imagery over the southern Appalachians to the FL Panhandle and central Gulf -- will shift eastward. By 00Z, the trough should extend from the Carolinas and coastal GA south-southwestward across northern FL and the extreme eastern Gulf. By 12Z, the trough should be offshore from the southern Atlantic Coast, including FL. At the surface, 11Z analysis showed a frontal-wave low over northeastern NC in the RDU/RWI area, with cold front across central portions of SC/GA to the west-central FL Panhandle and central Gulf. A prefrontal trough with northwesterly wind shift was drawn across southern GA, the FL coastal bend, and the east-central Gulf. A warm front -- poorly defined due to the presence of convection and dense precip on both sides -- was apparent from the low southeastward over parts of the Outer Banks. The low should move swiftly northeastward today, reaching near Montauk Point around 00Z, with the trailing cold front effectively catching the trough and moving offshore from the remainder of the Atlantic Coast (including FL). ...South FL/Keys... Widely scattered to scattered thunderstorms are possible through midafternoon in the destabilizing, prefrontal warm sector over south FL. The most vigorous cells may produce marginally severe gusts. The prefrontal air mass over the region will remain characterized by surface dewpoints around 68-72 F over most of south FL. Modified RAOBs and forecast soundings suggest this will support around 1000- 1500 J/kg MLCAPE with minimal CINH, and that convection now over parts of south FL already may be surface-based in the recovery zone of warm advection behind the prior night's activity. However, light and variable winds near the surface will become southwesterly to westerly through midday, while flow from just above the surface through 850 mb veers more. Though this will reduce hodograph size markedly, sufficient speed shear will remain to yield effective- shear magnitudes around 45-60 kt. Weak/intermittent supercell characteristics may be noted, while fast cell motions contribute to locally damaging downdrafts. ...Eastern NC... Somewhat organized thunderstorms extend from near HSE south- southwestward over Atlantic waters, moving northeastward. The most- intense activity should remain offshore where low-level instability and deep bulk shear each should be most favorable. Persistent overland precip has minimized buoyancy, and deep shear should continue to diminish as flow aloft weakens with time nearest the trough aloft. Behind the early precip area, some destabilization, related to both warm advection and patchy insolation, is expected diurnally. This may support isolated to widely scattered convection along/ahead of the cold front. However, with the low and associated isallobaric forcing moving quickly away from the region and up the Mid-Atlantic Coast through 18Z, warm-sector flow will veer, further reducing both vertical shear and low-level convergence. As such, unconditional potential appears too low to maintain a severe outlook. ..Edwards/Grams.. 03/23/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 AM CDT Sat Mar 23 2024 Valid 231300Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTH FLORIDA AND THE KEYS... ...SUMMARY... Isolated strong to severe thunderstorms may occur today across parts of south Florida and the Keys. ...Synopsis... In mid/upper levels, a series of shortwaves -- including the open- wave remnants of a cyclone now moving toward the Pacific Northwest Coast -- will contribute to development of a large synoptic trough over the West by 12Z tomorrow. Meanwhile, a downstream/southern- stream perturbation -- evident in moisture-channel imagery over the southern Appalachians to the FL Panhandle and central Gulf -- will shift eastward. By 00Z, the trough should extend from the Carolinas and coastal GA south-southwestward across northern FL and the extreme eastern Gulf. By 12Z, the trough should be offshore from the southern Atlantic Coast, including FL. At the surface, 11Z analysis showed a frontal-wave low over northeastern NC in the RDU/RWI area, with cold front across central portions of SC/GA to the west-central FL Panhandle and central Gulf. A prefrontal trough with northwesterly wind shift was drawn across southern GA, the FL coastal bend, and the east-central Gulf. A warm front -- poorly defined due to the presence of convection and dense precip on both sides -- was apparent from the low southeastward over parts of the Outer Banks. The low should move swiftly northeastward today, reaching near Montauk Point around 00Z, with the trailing cold front effectively catching the trough and moving offshore from the remainder of the Atlantic Coast (including FL). ...South FL/Keys... Widely scattered to scattered thunderstorms are possible through midafternoon in the destabilizing, prefrontal warm sector over south FL. The most vigorous cells may produce marginally severe gusts. The prefrontal air mass over the region will remain characterized by surface dewpoints around 68-72 F over most of south FL. Modified RAOBs and forecast soundings suggest this will support around 1000- 1500 J/kg MLCAPE with minimal CINH, and that convection now over parts of south FL already may be surface-based in the recovery zone of warm advection behind the prior night's activity. However, light and variable winds near the surface will become southwesterly to westerly through midday, while flow from just above the surface through 850 mb veers more. Though this will reduce hodograph size markedly, sufficient speed shear will remain to yield effective- shear magnitudes around 45-60 kt. Weak/intermittent supercell characteristics may be noted, while fast cell motions contribute to locally damaging downdrafts. ...Eastern NC... Somewhat organized thunderstorms extend from near HSE south- southwestward over Atlantic waters, moving northeastward. The most- intense activity should remain offshore where low-level instability and deep bulk shear each should be most favorable. Persistent overland precip has minimized buoyancy, and deep shear should continue to diminish as flow aloft weakens with time nearest the trough aloft. Behind the early precip area, some destabilization, related to both warm advection and patchy insolation, is expected diurnally. This may support isolated to widely scattered convection along/ahead of the cold front. However, with the low and associated isallobaric forcing moving quickly away from the region and up the Mid-Atlantic Coast through 18Z, warm-sector flow will veer, further reducing both vertical shear and low-level convergence. As such, unconditional potential appears too low to maintain a severe outlook. ..Edwards/Grams.. 03/23/2024 Read more

MD 0286 CONCERNING WINTER MIXED PRECIPITATION FOR PARTS OF NY INTO NEW ENGLAND
Mesoscale Discussion 0286 NWS Storm Prediction Center Norman OK 0227 AM CDT Sat Mar 23 2024 Areas affected...Parts of NY into New England Concerning...Winter mixed precipitation Valid 230727Z - 231130Z SUMMARY...A mix of heavy snow, sleet, and freezing rain will continue to spread east-northeast from parts of southern/eastern New York into New England through sunrise. Heavy snow rates of 1-1.5 in/hr will be most probable in a band along the northern periphery of the mixed transition zone. DISCUSSION...An extensive swath of mixed winter precip is ongoing across southern to eastern NY into parts of southern VT/NH. This has been aided by strong low-level warm theta-e advection amid a 50-60 kt low-level jet per ENX/BGM VWP data. Low-level warming has again been faster up the Hudson Valley than indicated by evening model guidance with prior 1"/hr snowfall rates at ALB transitioning to mixed freezing rain/sleet during the past hour. Based on recent radar trends, this mixed phase should be the dominant precip type as it gradually expands east-northeast into parts of MA and southern VT/NH in the next few hours. Precipitation rates from 0.04-0.12 in/hr should be expected based on upstream measurements/guidance. Heavier snowfall rates should still occur just to the north-northeast of the transition zone, with rates of 1-1.5 in/hr becoming increasingly probable across parts of northern VT/NH into a part of southwest ME through sunrise. ..Grams.. 03/23/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GYX...BOX...BTV...ALY...BGM... LAT...LON 43177514 44237427 44687330 44847126 44877067 44687024 44487007 44227007 43847030 43227079 42497163 42167269 41957319 41907382 41937419 42737528 43177514 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0352 AM CDT Sat Mar 23 2024 Valid 261200Z - 311200Z ...DISCUSSION... An isolated severe threat may persist into Day 4/Tuesday across parts of the lower MS Valley/central Gulf Coast and vicinity. The southern extent of a highly amplified upper trough will be present over these areas, with enhanced mid/upper-level flow supporting strong deep-layer shear and the potential for continued thunderstorm organization. However, the surface warm sector is likely to become increasingly confined to coastal portions of AL and the FL Panhandle through Tuesday afternoon/evening. This lowers confidence in appreciable inland destabilization occurring ahead of a cold front and thunderstorms likely to be ongoing Tuesday morning. Therefore, a 15% severe area has not been included for Tuesday. The southern portion of the upper trough should move slowly eastward across portions of the Southeast on Day 5/Wednesday. Rich low-level moisture should remain confined to parts of coastal GA/SC and FL. Severe potential across these areas appears fairly low given only weak instability is forecast to develop Wednesday afternoon. But, an isolated/marginal severe threat may exist in this narrow corridor ahead of a cold front. By Day 6/Thursday, medium-range guidance is in good agreement that the southern branch of upper troughing will advance more quickly eastward across the remainder of the Southeast. A related cold front should sweep eastward across the FL Peninsula through the day as a coastal low develops over/near the eastern Carolinas. While some severe threat may exist with any frontal convection, instability appears too weak to support inclusion of a 15% severe area for Thursday across FL. There are indications that by late next week and weekend, another upper trough may amplify as it moves over the western CONUS. Severe potential in this extended time frame will largely be tied to whether sufficient low-level moisture will be able to advance northward across the southern/central Plains as lee cyclogenesis occurs over the High Plains. At this point, it appears a somewhat better severe threat may exist beyond Day 8/Saturday. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0352 AM CDT Sat Mar 23 2024 Valid 261200Z - 311200Z ...DISCUSSION... An isolated severe threat may persist into Day 4/Tuesday across parts of the lower MS Valley/central Gulf Coast and vicinity. The southern extent of a highly amplified upper trough will be present over these areas, with enhanced mid/upper-level flow supporting strong deep-layer shear and the potential for continued thunderstorm organization. However, the surface warm sector is likely to become increasingly confined to coastal portions of AL and the FL Panhandle through Tuesday afternoon/evening. This lowers confidence in appreciable inland destabilization occurring ahead of a cold front and thunderstorms likely to be ongoing Tuesday morning. Therefore, a 15% severe area has not been included for Tuesday. The southern portion of the upper trough should move slowly eastward across portions of the Southeast on Day 5/Wednesday. Rich low-level moisture should remain confined to parts of coastal GA/SC and FL. Severe potential across these areas appears fairly low given only weak instability is forecast to develop Wednesday afternoon. But, an isolated/marginal severe threat may exist in this narrow corridor ahead of a cold front. By Day 6/Thursday, medium-range guidance is in good agreement that the southern branch of upper troughing will advance more quickly eastward across the remainder of the Southeast. A related cold front should sweep eastward across the FL Peninsula through the day as a coastal low develops over/near the eastern Carolinas. While some severe threat may exist with any frontal convection, instability appears too weak to support inclusion of a 15% severe area for Thursday across FL. There are indications that by late next week and weekend, another upper trough may amplify as it moves over the western CONUS. Severe potential in this extended time frame will largely be tied to whether sufficient low-level moisture will be able to advance northward across the southern/central Plains as lee cyclogenesis occurs over the High Plains. At this point, it appears a somewhat better severe threat may exist beyond Day 8/Saturday. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0352 AM CDT Sat Mar 23 2024 Valid 261200Z - 311200Z ...DISCUSSION... An isolated severe threat may persist into Day 4/Tuesday across parts of the lower MS Valley/central Gulf Coast and vicinity. The southern extent of a highly amplified upper trough will be present over these areas, with enhanced mid/upper-level flow supporting strong deep-layer shear and the potential for continued thunderstorm organization. However, the surface warm sector is likely to become increasingly confined to coastal portions of AL and the FL Panhandle through Tuesday afternoon/evening. This lowers confidence in appreciable inland destabilization occurring ahead of a cold front and thunderstorms likely to be ongoing Tuesday morning. Therefore, a 15% severe area has not been included for Tuesday. The southern portion of the upper trough should move slowly eastward across portions of the Southeast on Day 5/Wednesday. Rich low-level moisture should remain confined to parts of coastal GA/SC and FL. Severe potential across these areas appears fairly low given only weak instability is forecast to develop Wednesday afternoon. But, an isolated/marginal severe threat may exist in this narrow corridor ahead of a cold front. By Day 6/Thursday, medium-range guidance is in good agreement that the southern branch of upper troughing will advance more quickly eastward across the remainder of the Southeast. A related cold front should sweep eastward across the FL Peninsula through the day as a coastal low develops over/near the eastern Carolinas. While some severe threat may exist with any frontal convection, instability appears too weak to support inclusion of a 15% severe area for Thursday across FL. There are indications that by late next week and weekend, another upper trough may amplify as it moves over the western CONUS. Severe potential in this extended time frame will largely be tied to whether sufficient low-level moisture will be able to advance northward across the southern/central Plains as lee cyclogenesis occurs over the High Plains. At this point, it appears a somewhat better severe threat may exist beyond Day 8/Saturday. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0352 AM CDT Sat Mar 23 2024 Valid 261200Z - 311200Z ...DISCUSSION... An isolated severe threat may persist into Day 4/Tuesday across parts of the lower MS Valley/central Gulf Coast and vicinity. The southern extent of a highly amplified upper trough will be present over these areas, with enhanced mid/upper-level flow supporting strong deep-layer shear and the potential for continued thunderstorm organization. However, the surface warm sector is likely to become increasingly confined to coastal portions of AL and the FL Panhandle through Tuesday afternoon/evening. This lowers confidence in appreciable inland destabilization occurring ahead of a cold front and thunderstorms likely to be ongoing Tuesday morning. Therefore, a 15% severe area has not been included for Tuesday. The southern portion of the upper trough should move slowly eastward across portions of the Southeast on Day 5/Wednesday. Rich low-level moisture should remain confined to parts of coastal GA/SC and FL. Severe potential across these areas appears fairly low given only weak instability is forecast to develop Wednesday afternoon. But, an isolated/marginal severe threat may exist in this narrow corridor ahead of a cold front. By Day 6/Thursday, medium-range guidance is in good agreement that the southern branch of upper troughing will advance more quickly eastward across the remainder of the Southeast. A related cold front should sweep eastward across the FL Peninsula through the day as a coastal low develops over/near the eastern Carolinas. While some severe threat may exist with any frontal convection, instability appears too weak to support inclusion of a 15% severe area for Thursday across FL. There are indications that by late next week and weekend, another upper trough may amplify as it moves over the western CONUS. Severe potential in this extended time frame will largely be tied to whether sufficient low-level moisture will be able to advance northward across the southern/central Plains as lee cyclogenesis occurs over the High Plains. At this point, it appears a somewhat better severe threat may exist beyond Day 8/Saturday. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0352 AM CDT Sat Mar 23 2024 Valid 261200Z - 311200Z ...DISCUSSION... An isolated severe threat may persist into Day 4/Tuesday across parts of the lower MS Valley/central Gulf Coast and vicinity. The southern extent of a highly amplified upper trough will be present over these areas, with enhanced mid/upper-level flow supporting strong deep-layer shear and the potential for continued thunderstorm organization. However, the surface warm sector is likely to become increasingly confined to coastal portions of AL and the FL Panhandle through Tuesday afternoon/evening. This lowers confidence in appreciable inland destabilization occurring ahead of a cold front and thunderstorms likely to be ongoing Tuesday morning. Therefore, a 15% severe area has not been included for Tuesday. The southern portion of the upper trough should move slowly eastward across portions of the Southeast on Day 5/Wednesday. Rich low-level moisture should remain confined to parts of coastal GA/SC and FL. Severe potential across these areas appears fairly low given only weak instability is forecast to develop Wednesday afternoon. But, an isolated/marginal severe threat may exist in this narrow corridor ahead of a cold front. By Day 6/Thursday, medium-range guidance is in good agreement that the southern branch of upper troughing will advance more quickly eastward across the remainder of the Southeast. A related cold front should sweep eastward across the FL Peninsula through the day as a coastal low develops over/near the eastern Carolinas. While some severe threat may exist with any frontal convection, instability appears too weak to support inclusion of a 15% severe area for Thursday across FL. There are indications that by late next week and weekend, another upper trough may amplify as it moves over the western CONUS. Severe potential in this extended time frame will largely be tied to whether sufficient low-level moisture will be able to advance northward across the southern/central Plains as lee cyclogenesis occurs over the High Plains. At this point, it appears a somewhat better severe threat may exist beyond Day 8/Saturday. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0352 AM CDT Sat Mar 23 2024 Valid 261200Z - 311200Z ...DISCUSSION... An isolated severe threat may persist into Day 4/Tuesday across parts of the lower MS Valley/central Gulf Coast and vicinity. The southern extent of a highly amplified upper trough will be present over these areas, with enhanced mid/upper-level flow supporting strong deep-layer shear and the potential for continued thunderstorm organization. However, the surface warm sector is likely to become increasingly confined to coastal portions of AL and the FL Panhandle through Tuesday afternoon/evening. This lowers confidence in appreciable inland destabilization occurring ahead of a cold front and thunderstorms likely to be ongoing Tuesday morning. Therefore, a 15% severe area has not been included for Tuesday. The southern portion of the upper trough should move slowly eastward across portions of the Southeast on Day 5/Wednesday. Rich low-level moisture should remain confined to parts of coastal GA/SC and FL. Severe potential across these areas appears fairly low given only weak instability is forecast to develop Wednesday afternoon. But, an isolated/marginal severe threat may exist in this narrow corridor ahead of a cold front. By Day 6/Thursday, medium-range guidance is in good agreement that the southern branch of upper troughing will advance more quickly eastward across the remainder of the Southeast. A related cold front should sweep eastward across the FL Peninsula through the day as a coastal low develops over/near the eastern Carolinas. While some severe threat may exist with any frontal convection, instability appears too weak to support inclusion of a 15% severe area for Thursday across FL. There are indications that by late next week and weekend, another upper trough may amplify as it moves over the western CONUS. Severe potential in this extended time frame will largely be tied to whether sufficient low-level moisture will be able to advance northward across the southern/central Plains as lee cyclogenesis occurs over the High Plains. At this point, it appears a somewhat better severe threat may exist beyond Day 8/Saturday. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0352 AM CDT Sat Mar 23 2024 Valid 261200Z - 311200Z ...DISCUSSION... An isolated severe threat may persist into Day 4/Tuesday across parts of the lower MS Valley/central Gulf Coast and vicinity. The southern extent of a highly amplified upper trough will be present over these areas, with enhanced mid/upper-level flow supporting strong deep-layer shear and the potential for continued thunderstorm organization. However, the surface warm sector is likely to become increasingly confined to coastal portions of AL and the FL Panhandle through Tuesday afternoon/evening. This lowers confidence in appreciable inland destabilization occurring ahead of a cold front and thunderstorms likely to be ongoing Tuesday morning. Therefore, a 15% severe area has not been included for Tuesday. The southern portion of the upper trough should move slowly eastward across portions of the Southeast on Day 5/Wednesday. Rich low-level moisture should remain confined to parts of coastal GA/SC and FL. Severe potential across these areas appears fairly low given only weak instability is forecast to develop Wednesday afternoon. But, an isolated/marginal severe threat may exist in this narrow corridor ahead of a cold front. By Day 6/Thursday, medium-range guidance is in good agreement that the southern branch of upper troughing will advance more quickly eastward across the remainder of the Southeast. A related cold front should sweep eastward across the FL Peninsula through the day as a coastal low develops over/near the eastern Carolinas. While some severe threat may exist with any frontal convection, instability appears too weak to support inclusion of a 15% severe area for Thursday across FL. There are indications that by late next week and weekend, another upper trough may amplify as it moves over the western CONUS. Severe potential in this extended time frame will largely be tied to whether sufficient low-level moisture will be able to advance northward across the southern/central Plains as lee cyclogenesis occurs over the High Plains. At this point, it appears a somewhat better severe threat may exist beyond Day 8/Saturday. Read more

MD 0285 CONCERNING HEAVY SNOW FOR PORTIONS OF CENTRAL AND EASTERN NEW YORK INTO SOUTHERN VERMONT
Mesoscale Discussion 0285 NWS Storm Prediction Center Norman OK 1113 PM CDT Fri Mar 22 2024 Areas affected...portions of central and eastern New York into southern Vermont Concerning...Heavy snow Valid 230413Z - 230915Z SUMMARY...Periods of heavy snow are likely over the next several hours. 1+ inch/hr snowfall rates and reduced visibility are possible in the heaviest snow bands. DISCUSSION...925-850 mb warm-air advection continues to transport moisture into a sub-freezing troposphere amid a gradually amplifying mid-level trough approaching from the west. A shield of widespread moderate snow is already overspreading much of central and southern NY, with a couple instances of heavy snow already reported via surface observations. Increasing magnitudes and coverage of heavier snowfall rates (i.e. 1+ inches/hr) are expected to continue through the night as the approaching mid-level trough further amplifies and low-level warm-air advection persists. ..Squitieri.. 03/23/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BTV...ALY...BGM...BUF... LAT...LON 42667729 43177664 43567563 43577427 43507298 43357257 43027251 42837279 42587348 42457418 42487620 42667729 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Sat Mar 23 2024 Valid 251200Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF EAST TEXAS INTO THE LOWER MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms with a threat for a few tornadoes and damaging winds should occur Monday through Monday night from parts of east Texas into the lower Mississippi Valley. ...East Texas into the Lower Mississippi Valley... Large-scale upper troughing, with multiple embedded mid-level perturbations, is forecast to continue advancing eastward across the central CONUS on Monday. The primary feature of interest for severe potential will be a shortwave trough over northern Mexico and the southern Plains that will eject across the lower MS Valley by the end of the period. With the primary surface low over the Upper Midwest, a secondary low should develop across the lower MS Valley Monday evening and overnight into early Tuesday morning, as large-scale ascent preceding the shortwave trough overspreads the warm sector. A strong (40-60 kt) southerly low-level jet is also expected to develop in this time frame, which should aid in the transport of 60s surface dewpoints northward across LA/MS and southern AR. Thunderstorms may be ongoing at the start of the period Monday morning across parts of central/east TX along or just ahead of a cold front. Current expectations are for more robust convective development to occur by Monday afternoon across parts of east TX into LA, as at least weak instability develops in the presence of strong deep-layer shear. Updraft organization is anticipated, including the potential for pre-frontal supercells. But, this scenario remains rather uncertain. A greater likelihood exists for frontal convection in the form of a QLCS, posing a threat for both damaging winds and line-embedded tornadoes as it continues eastward across LA/MS and vicinity Monday evening into early Tuesday morning. The potential for nocturnal tornadoes is apparent, especially across northeastern LA into central/southern MS, as low-level shear should increase in tandem with the strengthening low-level jet. If confidence increases that supercells will develop ahead of the front/squall line, then greater severe probabilities would likely be needed. ...Iowa... A cold-core mid/upper trough will move quickly northeastward across the Upper Midwest Monday. Even though low-level moisture should remain quite limited, most guidance shows low 50s surface dewpoints present ahead of a deep surface low across IA Monday afternoon. Just modest daytime heating will support weak destabilization given the cold mid-level temperatures, and deep-layer shear appears strong enough for organized thunderstorms. Isolated hail, strong/gusty winds, and perhaps even a tornado or two all appear possible with any sustained low-topped convection. ..Gleason.. 03/23/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Sat Mar 23 2024 Valid 251200Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF EAST TEXAS INTO THE LOWER MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms with a threat for a few tornadoes and damaging winds should occur Monday through Monday night from parts of east Texas into the lower Mississippi Valley. ...East Texas into the Lower Mississippi Valley... Large-scale upper troughing, with multiple embedded mid-level perturbations, is forecast to continue advancing eastward across the central CONUS on Monday. The primary feature of interest for severe potential will be a shortwave trough over northern Mexico and the southern Plains that will eject across the lower MS Valley by the end of the period. With the primary surface low over the Upper Midwest, a secondary low should develop across the lower MS Valley Monday evening and overnight into early Tuesday morning, as large-scale ascent preceding the shortwave trough overspreads the warm sector. A strong (40-60 kt) southerly low-level jet is also expected to develop in this time frame, which should aid in the transport of 60s surface dewpoints northward across LA/MS and southern AR. Thunderstorms may be ongoing at the start of the period Monday morning across parts of central/east TX along or just ahead of a cold front. Current expectations are for more robust convective development to occur by Monday afternoon across parts of east TX into LA, as at least weak instability develops in the presence of strong deep-layer shear. Updraft organization is anticipated, including the potential for pre-frontal supercells. But, this scenario remains rather uncertain. A greater likelihood exists for frontal convection in the form of a QLCS, posing a threat for both damaging winds and line-embedded tornadoes as it continues eastward across LA/MS and vicinity Monday evening into early Tuesday morning. The potential for nocturnal tornadoes is apparent, especially across northeastern LA into central/southern MS, as low-level shear should increase in tandem with the strengthening low-level jet. If confidence increases that supercells will develop ahead of the front/squall line, then greater severe probabilities would likely be needed. ...Iowa... A cold-core mid/upper trough will move quickly northeastward across the Upper Midwest Monday. Even though low-level moisture should remain quite limited, most guidance shows low 50s surface dewpoints present ahead of a deep surface low across IA Monday afternoon. Just modest daytime heating will support weak destabilization given the cold mid-level temperatures, and deep-layer shear appears strong enough for organized thunderstorms. Isolated hail, strong/gusty winds, and perhaps even a tornado or two all appear possible with any sustained low-topped convection. ..Gleason.. 03/23/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Sat Mar 23 2024 Valid 251200Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF EAST TEXAS INTO THE LOWER MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms with a threat for a few tornadoes and damaging winds should occur Monday through Monday night from parts of east Texas into the lower Mississippi Valley. ...East Texas into the Lower Mississippi Valley... Large-scale upper troughing, with multiple embedded mid-level perturbations, is forecast to continue advancing eastward across the central CONUS on Monday. The primary feature of interest for severe potential will be a shortwave trough over northern Mexico and the southern Plains that will eject across the lower MS Valley by the end of the period. With the primary surface low over the Upper Midwest, a secondary low should develop across the lower MS Valley Monday evening and overnight into early Tuesday morning, as large-scale ascent preceding the shortwave trough overspreads the warm sector. A strong (40-60 kt) southerly low-level jet is also expected to develop in this time frame, which should aid in the transport of 60s surface dewpoints northward across LA/MS and southern AR. Thunderstorms may be ongoing at the start of the period Monday morning across parts of central/east TX along or just ahead of a cold front. Current expectations are for more robust convective development to occur by Monday afternoon across parts of east TX into LA, as at least weak instability develops in the presence of strong deep-layer shear. Updraft organization is anticipated, including the potential for pre-frontal supercells. But, this scenario remains rather uncertain. A greater likelihood exists for frontal convection in the form of a QLCS, posing a threat for both damaging winds and line-embedded tornadoes as it continues eastward across LA/MS and vicinity Monday evening into early Tuesday morning. The potential for nocturnal tornadoes is apparent, especially across northeastern LA into central/southern MS, as low-level shear should increase in tandem with the strengthening low-level jet. If confidence increases that supercells will develop ahead of the front/squall line, then greater severe probabilities would likely be needed. ...Iowa... A cold-core mid/upper trough will move quickly northeastward across the Upper Midwest Monday. Even though low-level moisture should remain quite limited, most guidance shows low 50s surface dewpoints present ahead of a deep surface low across IA Monday afternoon. Just modest daytime heating will support weak destabilization given the cold mid-level temperatures, and deep-layer shear appears strong enough for organized thunderstorms. Isolated hail, strong/gusty winds, and perhaps even a tornado or two all appear possible with any sustained low-topped convection. ..Gleason.. 03/23/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Sat Mar 23 2024 Valid 251200Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF EAST TEXAS INTO THE LOWER MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms with a threat for a few tornadoes and damaging winds should occur Monday through Monday night from parts of east Texas into the lower Mississippi Valley. ...East Texas into the Lower Mississippi Valley... Large-scale upper troughing, with multiple embedded mid-level perturbations, is forecast to continue advancing eastward across the central CONUS on Monday. The primary feature of interest for severe potential will be a shortwave trough over northern Mexico and the southern Plains that will eject across the lower MS Valley by the end of the period. With the primary surface low over the Upper Midwest, a secondary low should develop across the lower MS Valley Monday evening and overnight into early Tuesday morning, as large-scale ascent preceding the shortwave trough overspreads the warm sector. A strong (40-60 kt) southerly low-level jet is also expected to develop in this time frame, which should aid in the transport of 60s surface dewpoints northward across LA/MS and southern AR. Thunderstorms may be ongoing at the start of the period Monday morning across parts of central/east TX along or just ahead of a cold front. Current expectations are for more robust convective development to occur by Monday afternoon across parts of east TX into LA, as at least weak instability develops in the presence of strong deep-layer shear. Updraft organization is anticipated, including the potential for pre-frontal supercells. But, this scenario remains rather uncertain. A greater likelihood exists for frontal convection in the form of a QLCS, posing a threat for both damaging winds and line-embedded tornadoes as it continues eastward across LA/MS and vicinity Monday evening into early Tuesday morning. The potential for nocturnal tornadoes is apparent, especially across northeastern LA into central/southern MS, as low-level shear should increase in tandem with the strengthening low-level jet. If confidence increases that supercells will develop ahead of the front/squall line, then greater severe probabilities would likely be needed. ...Iowa... A cold-core mid/upper trough will move quickly northeastward across the Upper Midwest Monday. Even though low-level moisture should remain quite limited, most guidance shows low 50s surface dewpoints present ahead of a deep surface low across IA Monday afternoon. Just modest daytime heating will support weak destabilization given the cold mid-level temperatures, and deep-layer shear appears strong enough for organized thunderstorms. Isolated hail, strong/gusty winds, and perhaps even a tornado or two all appear possible with any sustained low-topped convection. ..Gleason.. 03/23/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Sat Mar 23 2024 Valid 251200Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF EAST TEXAS INTO THE LOWER MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms with a threat for a few tornadoes and damaging winds should occur Monday through Monday night from parts of east Texas into the lower Mississippi Valley. ...East Texas into the Lower Mississippi Valley... Large-scale upper troughing, with multiple embedded mid-level perturbations, is forecast to continue advancing eastward across the central CONUS on Monday. The primary feature of interest for severe potential will be a shortwave trough over northern Mexico and the southern Plains that will eject across the lower MS Valley by the end of the period. With the primary surface low over the Upper Midwest, a secondary low should develop across the lower MS Valley Monday evening and overnight into early Tuesday morning, as large-scale ascent preceding the shortwave trough overspreads the warm sector. A strong (40-60 kt) southerly low-level jet is also expected to develop in this time frame, which should aid in the transport of 60s surface dewpoints northward across LA/MS and southern AR. Thunderstorms may be ongoing at the start of the period Monday morning across parts of central/east TX along or just ahead of a cold front. Current expectations are for more robust convective development to occur by Monday afternoon across parts of east TX into LA, as at least weak instability develops in the presence of strong deep-layer shear. Updraft organization is anticipated, including the potential for pre-frontal supercells. But, this scenario remains rather uncertain. A greater likelihood exists for frontal convection in the form of a QLCS, posing a threat for both damaging winds and line-embedded tornadoes as it continues eastward across LA/MS and vicinity Monday evening into early Tuesday morning. The potential for nocturnal tornadoes is apparent, especially across northeastern LA into central/southern MS, as low-level shear should increase in tandem with the strengthening low-level jet. If confidence increases that supercells will develop ahead of the front/squall line, then greater severe probabilities would likely be needed. ...Iowa... A cold-core mid/upper trough will move quickly northeastward across the Upper Midwest Monday. Even though low-level moisture should remain quite limited, most guidance shows low 50s surface dewpoints present ahead of a deep surface low across IA Monday afternoon. Just modest daytime heating will support weak destabilization given the cold mid-level temperatures, and deep-layer shear appears strong enough for organized thunderstorms. Isolated hail, strong/gusty winds, and perhaps even a tornado or two all appear possible with any sustained low-topped convection. ..Gleason.. 03/23/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Sat Mar 23 2024 Valid 251200Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF EAST TEXAS INTO THE LOWER MISSISSIPPI VALLEY... ...SUMMARY... Scattered severe thunderstorms with a threat for a few tornadoes and damaging winds should occur Monday through Monday night from parts of east Texas into the lower Mississippi Valley. ...East Texas into the Lower Mississippi Valley... Large-scale upper troughing, with multiple embedded mid-level perturbations, is forecast to continue advancing eastward across the central CONUS on Monday. The primary feature of interest for severe potential will be a shortwave trough over northern Mexico and the southern Plains that will eject across the lower MS Valley by the end of the period. With the primary surface low over the Upper Midwest, a secondary low should develop across the lower MS Valley Monday evening and overnight into early Tuesday morning, as large-scale ascent preceding the shortwave trough overspreads the warm sector. A strong (40-60 kt) southerly low-level jet is also expected to develop in this time frame, which should aid in the transport of 60s surface dewpoints northward across LA/MS and southern AR. Thunderstorms may be ongoing at the start of the period Monday morning across parts of central/east TX along or just ahead of a cold front. Current expectations are for more robust convective development to occur by Monday afternoon across parts of east TX into LA, as at least weak instability develops in the presence of strong deep-layer shear. Updraft organization is anticipated, including the potential for pre-frontal supercells. But, this scenario remains rather uncertain. A greater likelihood exists for frontal convection in the form of a QLCS, posing a threat for both damaging winds and line-embedded tornadoes as it continues eastward across LA/MS and vicinity Monday evening into early Tuesday morning. The potential for nocturnal tornadoes is apparent, especially across northeastern LA into central/southern MS, as low-level shear should increase in tandem with the strengthening low-level jet. If confidence increases that supercells will develop ahead of the front/squall line, then greater severe probabilities would likely be needed. ...Iowa... A cold-core mid/upper trough will move quickly northeastward across the Upper Midwest Monday. Even though low-level moisture should remain quite limited, most guidance shows low 50s surface dewpoints present ahead of a deep surface low across IA Monday afternoon. Just modest daytime heating will support weak destabilization given the cold mid-level temperatures, and deep-layer shear appears strong enough for organized thunderstorms. Isolated hail, strong/gusty winds, and perhaps even a tornado or two all appear possible with any sustained low-topped convection. ..Gleason.. 03/23/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0128 AM CDT Sat Mar 23 2024 Valid 241200Z - 251200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...Synopsis... A pronounced mid-level trough will eject into the Plains tomorrow/Sunday, supporting the rapid deepening of a surface cyclone over the central High Plains. Strong westerly surface winds will become prevalent behind the dryline over the central and southern High Plains during the afternoon, with potentially dangerous fire weather conditions becoming likely. By afternoon peak heating, 30+ mph sustained west-southwesterly surface winds (with higher gusts) will coincide with 15-20 percent RH for several hours across portions of southwestern Kansas into the Oklahoma/Texas Panhandles, west-central Texas, and far southeastern New Mexico. While fuel receptiveness will not be extremely robust, the loading of dormant fuels remnant from the 2023 season will compensate to support high-end Critical wildfire-spread potential, given the very windy and dry meteorological surface conditions. Dry, occasionally breezy conditions are also possible across portions of the mid-Mississippi Valley tomorrow/Sunday afternoon. While guidance consensus does not strongly favor overlapping Elevated surface winds/RH across eastern Missouri into Indiana, this region has experienced a lack of appreciable rainfall in the past week and remains under drought conditions. As such, instances of localized wildfire spread may occur Sunday afternoon. ..Squitieri.. 03/23/2024 ...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 0128 AM CDT Sat Mar 23 2024 Valid 241200Z - 251200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...Synopsis... A pronounced mid-level trough will eject into the Plains tomorrow/Sunday, supporting the rapid deepening of a surface cyclone over the central High Plains. Strong westerly surface winds will become prevalent behind the dryline over the central and southern High Plains during the afternoon, with potentially dangerous fire weather conditions becoming likely. By afternoon peak heating, 30+ mph sustained west-southwesterly surface winds (with higher gusts) will coincide with 15-20 percent RH for several hours across portions of southwestern Kansas into the Oklahoma/Texas Panhandles, west-central Texas, and far southeastern New Mexico. While fuel receptiveness will not be extremely robust, the loading of dormant fuels remnant from the 2023 season will compensate to support high-end Critical wildfire-spread potential, given the very windy and dry meteorological surface conditions. Dry, occasionally breezy conditions are also possible across portions of the mid-Mississippi Valley tomorrow/Sunday afternoon. While guidance consensus does not strongly favor overlapping Elevated surface winds/RH across eastern Missouri into Indiana, this region has experienced a lack of appreciable rainfall in the past week and remains under drought conditions. As such, instances of localized wildfire spread may occur Sunday afternoon. ..Squitieri.. 03/23/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more