Severe Storms

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1026 AM CST Wed Dec 11 2024 Valid 111630Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EARLY EVENING FROM EASTERN NC INTO SOUTHERN NEW ENGLAND... ...SUMMARY... Severe thunderstorm winds and a few tornadoes are possible from the eastern Carolinas to southern New England. Isolated severe thunderstorms may occur southward into portions of Florida. ...Delmarva region into the Carolinas... A large and fast-moving upper trough is tracking across the TN Valley and Gulf Coast region today, with the associated surface cold front sweeping toward the East Coast. Low and mid level wind fields are very strong ahead of the front, with VAD observations and model guidance suggesting 50-70 knot southwesterly flow in the 1-2km layer throughout the area. This will lead to a conditional risk of damaging winds and tornadoes in organized thunderstorms that can develop. However, thermodynamics are quite weak, limiting overall confidence in the extent of severe activity later today. Morning CAM solutions continue to suggest the development of a fine-line of convection this afternoon along the front from the Delmarva region southward into the Carolinas. This appears to be the area of highest confidence in locally gusty/damaging thunderstorm winds and a tornado or two. ...Southern New England... Rapid surface cyclogenesis and intense low-level wind fields will result in some risk of damaging winds in the fast-moving showers that affect Southern New England this afternoon. Forecast soundings show very weak instability, suggesting that frontal activity may struggle to develop robust updrafts/lightning. Will maintain the ongoing SLGT due to the conditional risk, but confidence in the coverage of severe weather is not very high. ...FL... The southern end of the frontal band of convection will sweep across the FL Peninsula this afternoon, with scattered thunderstorms expected to continue. This area will be farthest removed from the synoptic system, but will have better low level moisture/instability. A few strong storms are expected, capable of gusty winds and perhaps a tornado. ..Hart/Squitieri.. 12/11/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1026 AM CST Wed Dec 11 2024 Valid 111630Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EARLY EVENING FROM EASTERN NC INTO SOUTHERN NEW ENGLAND... ...SUMMARY... Severe thunderstorm winds and a few tornadoes are possible from the eastern Carolinas to southern New England. Isolated severe thunderstorms may occur southward into portions of Florida. ...Delmarva region into the Carolinas... A large and fast-moving upper trough is tracking across the TN Valley and Gulf Coast region today, with the associated surface cold front sweeping toward the East Coast. Low and mid level wind fields are very strong ahead of the front, with VAD observations and model guidance suggesting 50-70 knot southwesterly flow in the 1-2km layer throughout the area. This will lead to a conditional risk of damaging winds and tornadoes in organized thunderstorms that can develop. However, thermodynamics are quite weak, limiting overall confidence in the extent of severe activity later today. Morning CAM solutions continue to suggest the development of a fine-line of convection this afternoon along the front from the Delmarva region southward into the Carolinas. This appears to be the area of highest confidence in locally gusty/damaging thunderstorm winds and a tornado or two. ...Southern New England... Rapid surface cyclogenesis and intense low-level wind fields will result in some risk of damaging winds in the fast-moving showers that affect Southern New England this afternoon. Forecast soundings show very weak instability, suggesting that frontal activity may struggle to develop robust updrafts/lightning. Will maintain the ongoing SLGT due to the conditional risk, but confidence in the coverage of severe weather is not very high. ...FL... The southern end of the frontal band of convection will sweep across the FL Peninsula this afternoon, with scattered thunderstorms expected to continue. This area will be farthest removed from the synoptic system, but will have better low level moisture/instability. A few strong storms are expected, capable of gusty winds and perhaps a tornado. ..Hart/Squitieri.. 12/11/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0639 AM CST Wed Dec 11 2024 Valid 111300Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE EASTERN CAROLINAS TO SOUTHERN NEW ENGLAND... ...SUMMARY... Severe thunderstorm winds and a few tornadoes are possible from the eastern Carolinas to southern New England. Isolated severe thunderstorms may occur southward into portions of Florida. ...Synopsis... Moisture-channel imagery showed a substantial mid/upper trough extending from a cyclone over the MB/ON border southward over the Mississippi Valley to a strong, basal shortwave trough over portions of MS/LA. The latter feature is forecast to pivot eastward to the TN Valley and FL Panhandle through 18Z, then turn northeastward across WV, western VA and the west-central Carolinas by 00Z. As that occurs, the entire synoptic trough will become more negatively tilted, with preceding speed maxima of 160-180-kt at 250 mb, 110-125 kt at 500 mb, and 70-85 kt at 700 mb over parts of the Atlantic Coast States. A cold front precedes the main mid/upper trough, and was analyzed at 11Z from east-central PA over western VA to a weak low near AVL, then across central/southwestern GA and the west-central FL Panhandle, to the central Gulf. The front should sweep eastward across VA, the Carolinas, GA and most of FL today, with a 00Z position progged from VT across western Long Island, over Atlantic waters to near or just offshore HSE, then southwestward over more of the Atlantic to southeastern FL. The front should proceed offshore from the remaining Atlantic Coast by around 12Z tomorrow. ...East Coast States... An ongoing, prefrontal band of convection, with scattered to widely scattered embedded thunderstorms, was apparent in radar, satellite and lightning data from the northeastern Gulf northeastward across the FL Big Bend region and southern/eastern GA. This activity should proceed eastward across much of FL and offshore from GA today, with isolated potential for damaging to severe gusts and/or a tornado, as it encounters foregoing diabatic surface destabilization and boundary-layer theta-e advection. The main changes this cycle are to the associated "marginal area, to: 1. Trim on the southwest edge in deference to ongoing convective trends (faster than earlier guidance), and 2. Add somewhat more of central/southwestern FL to the 5%-wind/Marginal area to give the trailing part of the main squall line more room to weaken, as diurnal heating of a moist airmass somewhat offsets weakening trends in both large-scale and frontal forcings. Meanwhile, the most dense potential for damaging to severe gusts is expected to develop farther north today across central/eastern parts of the Carolinas, northeastward along the coast into southern New England. As the shortwave and synoptic troughs assume negative tilt, synoptic to frontal-scale lift will increase and overlap, resulting in a narrow band of convection (some with lightning, but potentially a majority without) firming up into the Mid-Atlantic and perhaps southern New England. The aforementioned deep-layer wind maxima will contribute to fast embedded cell motions and downward momentum transfer within this band. Intense associated gusts sporadically should penetrate a deeply near-neutral to slightly above moist-adiabatic layer of lapse rates -- with a shallow near-surface absolutely stable layer possible -- from around the Delmarva region northeastward, beneath MUCAPE of around 300-800 J/kg. Buoyancy will become more surface-based with southern extent from southeastern VA southward, with the greatest values of low-level shear/SRH and largest hodographs expected over eastern NC in and near the area of relatively peaked tornado probabilities. Line-embedded supercells and/or QLCS mesovortices will be the main tornado concern, with the wind threat more generalized to any sustained, bow/LEWP segments within the line. ..Edwards/Jewell.. 12/11/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0639 AM CST Wed Dec 11 2024 Valid 111300Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE EASTERN CAROLINAS TO SOUTHERN NEW ENGLAND... ...SUMMARY... Severe thunderstorm winds and a few tornadoes are possible from the eastern Carolinas to southern New England. Isolated severe thunderstorms may occur southward into portions of Florida. ...Synopsis... Moisture-channel imagery showed a substantial mid/upper trough extending from a cyclone over the MB/ON border southward over the Mississippi Valley to a strong, basal shortwave trough over portions of MS/LA. The latter feature is forecast to pivot eastward to the TN Valley and FL Panhandle through 18Z, then turn northeastward across WV, western VA and the west-central Carolinas by 00Z. As that occurs, the entire synoptic trough will become more negatively tilted, with preceding speed maxima of 160-180-kt at 250 mb, 110-125 kt at 500 mb, and 70-85 kt at 700 mb over parts of the Atlantic Coast States. A cold front precedes the main mid/upper trough, and was analyzed at 11Z from east-central PA over western VA to a weak low near AVL, then across central/southwestern GA and the west-central FL Panhandle, to the central Gulf. The front should sweep eastward across VA, the Carolinas, GA and most of FL today, with a 00Z position progged from VT across western Long Island, over Atlantic waters to near or just offshore HSE, then southwestward over more of the Atlantic to southeastern FL. The front should proceed offshore from the remaining Atlantic Coast by around 12Z tomorrow. ...East Coast States... An ongoing, prefrontal band of convection, with scattered to widely scattered embedded thunderstorms, was apparent in radar, satellite and lightning data from the northeastern Gulf northeastward across the FL Big Bend region and southern/eastern GA. This activity should proceed eastward across much of FL and offshore from GA today, with isolated potential for damaging to severe gusts and/or a tornado, as it encounters foregoing diabatic surface destabilization and boundary-layer theta-e advection. The main changes this cycle are to the associated "marginal area, to: 1. Trim on the southwest edge in deference to ongoing convective trends (faster than earlier guidance), and 2. Add somewhat more of central/southwestern FL to the 5%-wind/Marginal area to give the trailing part of the main squall line more room to weaken, as diurnal heating of a moist airmass somewhat offsets weakening trends in both large-scale and frontal forcings. Meanwhile, the most dense potential for damaging to severe gusts is expected to develop farther north today across central/eastern parts of the Carolinas, northeastward along the coast into southern New England. As the shortwave and synoptic troughs assume negative tilt, synoptic to frontal-scale lift will increase and overlap, resulting in a narrow band of convection (some with lightning, but potentially a majority without) firming up into the Mid-Atlantic and perhaps southern New England. The aforementioned deep-layer wind maxima will contribute to fast embedded cell motions and downward momentum transfer within this band. Intense associated gusts sporadically should penetrate a deeply near-neutral to slightly above moist-adiabatic layer of lapse rates -- with a shallow near-surface absolutely stable layer possible -- from around the Delmarva region northeastward, beneath MUCAPE of around 300-800 J/kg. Buoyancy will become more surface-based with southern extent from southeastern VA southward, with the greatest values of low-level shear/SRH and largest hodographs expected over eastern NC in and near the area of relatively peaked tornado probabilities. Line-embedded supercells and/or QLCS mesovortices will be the main tornado concern, with the wind threat more generalized to any sustained, bow/LEWP segments within the line. ..Edwards/Jewell.. 12/11/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0639 AM CST Wed Dec 11 2024 Valid 111300Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE EASTERN CAROLINAS TO SOUTHERN NEW ENGLAND... ...SUMMARY... Severe thunderstorm winds and a few tornadoes are possible from the eastern Carolinas to southern New England. Isolated severe thunderstorms may occur southward into portions of Florida. ...Synopsis... Moisture-channel imagery showed a substantial mid/upper trough extending from a cyclone over the MB/ON border southward over the Mississippi Valley to a strong, basal shortwave trough over portions of MS/LA. The latter feature is forecast to pivot eastward to the TN Valley and FL Panhandle through 18Z, then turn northeastward across WV, western VA and the west-central Carolinas by 00Z. As that occurs, the entire synoptic trough will become more negatively tilted, with preceding speed maxima of 160-180-kt at 250 mb, 110-125 kt at 500 mb, and 70-85 kt at 700 mb over parts of the Atlantic Coast States. A cold front precedes the main mid/upper trough, and was analyzed at 11Z from east-central PA over western VA to a weak low near AVL, then across central/southwestern GA and the west-central FL Panhandle, to the central Gulf. The front should sweep eastward across VA, the Carolinas, GA and most of FL today, with a 00Z position progged from VT across western Long Island, over Atlantic waters to near or just offshore HSE, then southwestward over more of the Atlantic to southeastern FL. The front should proceed offshore from the remaining Atlantic Coast by around 12Z tomorrow. ...East Coast States... An ongoing, prefrontal band of convection, with scattered to widely scattered embedded thunderstorms, was apparent in radar, satellite and lightning data from the northeastern Gulf northeastward across the FL Big Bend region and southern/eastern GA. This activity should proceed eastward across much of FL and offshore from GA today, with isolated potential for damaging to severe gusts and/or a tornado, as it encounters foregoing diabatic surface destabilization and boundary-layer theta-e advection. The main changes this cycle are to the associated "marginal area, to: 1. Trim on the southwest edge in deference to ongoing convective trends (faster than earlier guidance), and 2. Add somewhat more of central/southwestern FL to the 5%-wind/Marginal area to give the trailing part of the main squall line more room to weaken, as diurnal heating of a moist airmass somewhat offsets weakening trends in both large-scale and frontal forcings. Meanwhile, the most dense potential for damaging to severe gusts is expected to develop farther north today across central/eastern parts of the Carolinas, northeastward along the coast into southern New England. As the shortwave and synoptic troughs assume negative tilt, synoptic to frontal-scale lift will increase and overlap, resulting in a narrow band of convection (some with lightning, but potentially a majority without) firming up into the Mid-Atlantic and perhaps southern New England. The aforementioned deep-layer wind maxima will contribute to fast embedded cell motions and downward momentum transfer within this band. Intense associated gusts sporadically should penetrate a deeply near-neutral to slightly above moist-adiabatic layer of lapse rates -- with a shallow near-surface absolutely stable layer possible -- from around the Delmarva region northeastward, beneath MUCAPE of around 300-800 J/kg. Buoyancy will become more surface-based with southern extent from southeastern VA southward, with the greatest values of low-level shear/SRH and largest hodographs expected over eastern NC in and near the area of relatively peaked tornado probabilities. Line-embedded supercells and/or QLCS mesovortices will be the main tornado concern, with the wind threat more generalized to any sustained, bow/LEWP segments within the line. ..Edwards/Jewell.. 12/11/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0639 AM CST Wed Dec 11 2024 Valid 111300Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE EASTERN CAROLINAS TO SOUTHERN NEW ENGLAND... ...SUMMARY... Severe thunderstorm winds and a few tornadoes are possible from the eastern Carolinas to southern New England. Isolated severe thunderstorms may occur southward into portions of Florida. ...Synopsis... Moisture-channel imagery showed a substantial mid/upper trough extending from a cyclone over the MB/ON border southward over the Mississippi Valley to a strong, basal shortwave trough over portions of MS/LA. The latter feature is forecast to pivot eastward to the TN Valley and FL Panhandle through 18Z, then turn northeastward across WV, western VA and the west-central Carolinas by 00Z. As that occurs, the entire synoptic trough will become more negatively tilted, with preceding speed maxima of 160-180-kt at 250 mb, 110-125 kt at 500 mb, and 70-85 kt at 700 mb over parts of the Atlantic Coast States. A cold front precedes the main mid/upper trough, and was analyzed at 11Z from east-central PA over western VA to a weak low near AVL, then across central/southwestern GA and the west-central FL Panhandle, to the central Gulf. The front should sweep eastward across VA, the Carolinas, GA and most of FL today, with a 00Z position progged from VT across western Long Island, over Atlantic waters to near or just offshore HSE, then southwestward over more of the Atlantic to southeastern FL. The front should proceed offshore from the remaining Atlantic Coast by around 12Z tomorrow. ...East Coast States... An ongoing, prefrontal band of convection, with scattered to widely scattered embedded thunderstorms, was apparent in radar, satellite and lightning data from the northeastern Gulf northeastward across the FL Big Bend region and southern/eastern GA. This activity should proceed eastward across much of FL and offshore from GA today, with isolated potential for damaging to severe gusts and/or a tornado, as it encounters foregoing diabatic surface destabilization and boundary-layer theta-e advection. The main changes this cycle are to the associated "marginal area, to: 1. Trim on the southwest edge in deference to ongoing convective trends (faster than earlier guidance), and 2. Add somewhat more of central/southwestern FL to the 5%-wind/Marginal area to give the trailing part of the main squall line more room to weaken, as diurnal heating of a moist airmass somewhat offsets weakening trends in both large-scale and frontal forcings. Meanwhile, the most dense potential for damaging to severe gusts is expected to develop farther north today across central/eastern parts of the Carolinas, northeastward along the coast into southern New England. As the shortwave and synoptic troughs assume negative tilt, synoptic to frontal-scale lift will increase and overlap, resulting in a narrow band of convection (some with lightning, but potentially a majority without) firming up into the Mid-Atlantic and perhaps southern New England. The aforementioned deep-layer wind maxima will contribute to fast embedded cell motions and downward momentum transfer within this band. Intense associated gusts sporadically should penetrate a deeply near-neutral to slightly above moist-adiabatic layer of lapse rates -- with a shallow near-surface absolutely stable layer possible -- from around the Delmarva region northeastward, beneath MUCAPE of around 300-800 J/kg. Buoyancy will become more surface-based with southern extent from southeastern VA southward, with the greatest values of low-level shear/SRH and largest hodographs expected over eastern NC in and near the area of relatively peaked tornado probabilities. Line-embedded supercells and/or QLCS mesovortices will be the main tornado concern, with the wind threat more generalized to any sustained, bow/LEWP segments within the line. ..Edwards/Jewell.. 12/11/2024 Read more

MD 2259 CONCERNING FREEZING RAIN FOR SOUTHERN MAINE
Mesoscale Discussion 2259 NWS Storm Prediction Center Norman OK 0215 AM CST Wed Dec 11 2024 Areas affected...Southern Maine Concerning...Freezing rain Valid 110815Z - 111215Z SUMMARY...Light to moderate freezing rain appears likely through 12 UTC across parts of southern Maine. DISCUSSION...Recent surface observations from southern ME have reported a wintry mix of light freezing rain and snow over the past hour as light precipitation migrates over the region. The 00 UTC GYX sounding sampled sub-freezing surface temperatures in the upper 20s with a 2 C warm nose at around 850 mb. This warm nose is expected to intensify through 12 UTC, amid strengthening low to mid-level warm air advection, within the warm conveyor belt of an intensifying cyclone. This should promote a change over from a wintry mix to predominantly liquid hydrometeors over the next couple of hours. Latest surface analyses/observations show the surface warm front remains well displaced to the south, so the shallow sub-freezing layer should remain in place through sunrise. Light precipitation should continue as isentropic ascent increases, but precipitation rates will increase closer to 10-12 UTC as a broader plume of stratiform rain (associated with deeper large-scale ascent and closer to the surface warm front) migrates from New England northeast into southern ME. It remains unclear how surface temperatures will respond as this precipitation approaches, given the coincident arrival of the surface warm front. However, latest high-res guidance suggests the sub-freezing layer will persist long enough to realize moderate freezing rain rates between 10-12 UTC, especially within deeper valleys. ..Moore.. 12/11/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CAR...GYX... LAT...LON 43927097 44437066 44847012 45106936 45156876 45096831 44936819 44696829 44626860 44386910 43996980 43727015 43517051 43487072 43547087 43647093 43927097 Read more

MD 2258 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR THE FLORIDA PANHANDLE INTO SOUTHWEST GEORGIA
Mesoscale Discussion 2258 NWS Storm Prediction Center Norman OK 0142 AM CST Wed Dec 11 2024 Areas affected...the Florida Panhandle into southwest Georgia Concerning...Severe potential...Watch unlikely Valid 110742Z - 111115Z Probability of Watch Issuance...20 percent SUMMARY...A gradual increase in thunderstorms is expected from parts of the Florida Panhandle into southwest Georgia, and isolated severe cannot be ruled out. DISCUSSION...Surface analysis shows a cold front extending from northern GA across southeast AL and into the northeast Gulf of Mexico. Meanwhile, a north-south oriented warm front remains draped across central GA into northern FL. MLCAPE over 500 J/kg exists across the warm sector currently, where upper 60s F dewpoints are prevalent. Also of note, are surface gusts in the 15-20 kt range, indicated a degree of boundary-layer mixing. Area VWPs show southwest winds around 40 kt about 1 km off the surface, which results in 0-1 km SRH over 100 m2/s2 near the coast to over 200 m2/s2 near the GA warm front. As such, any increase in convection tonight along or just ahead of the cold front could result in a brief tornado or damaging-wind risk, but coverage of severe is not expected to necessitate a watch. ..Jewell.. 12/11/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...JAX...FFC...TAE... LAT...LON 29908596 30808517 31968448 32528410 33078376 33198340 33148292 32788271 32218274 31268288 30788311 29978371 29488454 29488513 29618574 29908596 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0348 AM CST Wed Dec 11 2024 Valid 141200Z - 191200Z ...DISCUSSION... A progressive upper pattern is expected in the extended, with several low-amplitude shortwave troughs forecast to traverse the CONUS. Lead shortwave in this series will likely be over the central Plains on D4/Saturday morning before then moving through the Mid MS Valley by late D4/Saturday and through the OH Valley on D5/Sunday. Another shortwave is expected to follow in the wake of the first, progressing across the Great Basin and Four Corners on D5/Sunday and the southern/central Plains on D6/Monday. This wave may phase with another shortwave moving through central Canada, with resultant troughing extended from the Canadian Prairies into the southern Plains by D6/Monday afternoon. Yet another shortwave is currently progged to drop from the Pacific Northwest/northern CA into the Great Basin late D6/Monday. Guidance varies significantly on the evolution of this wave, and its strength/maturity and location currently have limited predictability. Moisture return is anticipated across the Plains ahead of each of these waves. Enough moisture and buoyancy should exist ahead of the first shortwave to support thunderstorms, as it moves eastward on into the MS Valley on D4/Saturday and through the remainder of the eastern CONUS on D5/Sunday. The most significant moisture return is currently expected ahead of the second shortwave on D5/Sunday and D6/Monday. Thunderstorms are likely as the shortwave and associated cold front interact with this return moisture, although variability within the guidance of the strength and speed of this wave results in differing areas of highest thunderstorm coverage. Some severe appears possible, particularly if the wave is stronger and further south as suggested by the 00Z ECMWF. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0348 AM CST Wed Dec 11 2024 Valid 141200Z - 191200Z ...DISCUSSION... A progressive upper pattern is expected in the extended, with several low-amplitude shortwave troughs forecast to traverse the CONUS. Lead shortwave in this series will likely be over the central Plains on D4/Saturday morning before then moving through the Mid MS Valley by late D4/Saturday and through the OH Valley on D5/Sunday. Another shortwave is expected to follow in the wake of the first, progressing across the Great Basin and Four Corners on D5/Sunday and the southern/central Plains on D6/Monday. This wave may phase with another shortwave moving through central Canada, with resultant troughing extended from the Canadian Prairies into the southern Plains by D6/Monday afternoon. Yet another shortwave is currently progged to drop from the Pacific Northwest/northern CA into the Great Basin late D6/Monday. Guidance varies significantly on the evolution of this wave, and its strength/maturity and location currently have limited predictability. Moisture return is anticipated across the Plains ahead of each of these waves. Enough moisture and buoyancy should exist ahead of the first shortwave to support thunderstorms, as it moves eastward on into the MS Valley on D4/Saturday and through the remainder of the eastern CONUS on D5/Sunday. The most significant moisture return is currently expected ahead of the second shortwave on D5/Sunday and D6/Monday. Thunderstorms are likely as the shortwave and associated cold front interact with this return moisture, although variability within the guidance of the strength and speed of this wave results in differing areas of highest thunderstorm coverage. Some severe appears possible, particularly if the wave is stronger and further south as suggested by the 00Z ECMWF. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0348 AM CST Wed Dec 11 2024 Valid 141200Z - 191200Z ...DISCUSSION... A progressive upper pattern is expected in the extended, with several low-amplitude shortwave troughs forecast to traverse the CONUS. Lead shortwave in this series will likely be over the central Plains on D4/Saturday morning before then moving through the Mid MS Valley by late D4/Saturday and through the OH Valley on D5/Sunday. Another shortwave is expected to follow in the wake of the first, progressing across the Great Basin and Four Corners on D5/Sunday and the southern/central Plains on D6/Monday. This wave may phase with another shortwave moving through central Canada, with resultant troughing extended from the Canadian Prairies into the southern Plains by D6/Monday afternoon. Yet another shortwave is currently progged to drop from the Pacific Northwest/northern CA into the Great Basin late D6/Monday. Guidance varies significantly on the evolution of this wave, and its strength/maturity and location currently have limited predictability. Moisture return is anticipated across the Plains ahead of each of these waves. Enough moisture and buoyancy should exist ahead of the first shortwave to support thunderstorms, as it moves eastward on into the MS Valley on D4/Saturday and through the remainder of the eastern CONUS on D5/Sunday. The most significant moisture return is currently expected ahead of the second shortwave on D5/Sunday and D6/Monday. Thunderstorms are likely as the shortwave and associated cold front interact with this return moisture, although variability within the guidance of the strength and speed of this wave results in differing areas of highest thunderstorm coverage. Some severe appears possible, particularly if the wave is stronger and further south as suggested by the 00Z ECMWF. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0348 AM CST Wed Dec 11 2024 Valid 141200Z - 191200Z ...DISCUSSION... A progressive upper pattern is expected in the extended, with several low-amplitude shortwave troughs forecast to traverse the CONUS. Lead shortwave in this series will likely be over the central Plains on D4/Saturday morning before then moving through the Mid MS Valley by late D4/Saturday and through the OH Valley on D5/Sunday. Another shortwave is expected to follow in the wake of the first, progressing across the Great Basin and Four Corners on D5/Sunday and the southern/central Plains on D6/Monday. This wave may phase with another shortwave moving through central Canada, with resultant troughing extended from the Canadian Prairies into the southern Plains by D6/Monday afternoon. Yet another shortwave is currently progged to drop from the Pacific Northwest/northern CA into the Great Basin late D6/Monday. Guidance varies significantly on the evolution of this wave, and its strength/maturity and location currently have limited predictability. Moisture return is anticipated across the Plains ahead of each of these waves. Enough moisture and buoyancy should exist ahead of the first shortwave to support thunderstorms, as it moves eastward on into the MS Valley on D4/Saturday and through the remainder of the eastern CONUS on D5/Sunday. The most significant moisture return is currently expected ahead of the second shortwave on D5/Sunday and D6/Monday. Thunderstorms are likely as the shortwave and associated cold front interact with this return moisture, although variability within the guidance of the strength and speed of this wave results in differing areas of highest thunderstorm coverage. Some severe appears possible, particularly if the wave is stronger and further south as suggested by the 00Z ECMWF. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0348 AM CST Wed Dec 11 2024 Valid 141200Z - 191200Z ...DISCUSSION... A progressive upper pattern is expected in the extended, with several low-amplitude shortwave troughs forecast to traverse the CONUS. Lead shortwave in this series will likely be over the central Plains on D4/Saturday morning before then moving through the Mid MS Valley by late D4/Saturday and through the OH Valley on D5/Sunday. Another shortwave is expected to follow in the wake of the first, progressing across the Great Basin and Four Corners on D5/Sunday and the southern/central Plains on D6/Monday. This wave may phase with another shortwave moving through central Canada, with resultant troughing extended from the Canadian Prairies into the southern Plains by D6/Monday afternoon. Yet another shortwave is currently progged to drop from the Pacific Northwest/northern CA into the Great Basin late D6/Monday. Guidance varies significantly on the evolution of this wave, and its strength/maturity and location currently have limited predictability. Moisture return is anticipated across the Plains ahead of each of these waves. Enough moisture and buoyancy should exist ahead of the first shortwave to support thunderstorms, as it moves eastward on into the MS Valley on D4/Saturday and through the remainder of the eastern CONUS on D5/Sunday. The most significant moisture return is currently expected ahead of the second shortwave on D5/Sunday and D6/Monday. Thunderstorms are likely as the shortwave and associated cold front interact with this return moisture, although variability within the guidance of the strength and speed of this wave results in differing areas of highest thunderstorm coverage. Some severe appears possible, particularly if the wave is stronger and further south as suggested by the 00Z ECMWF. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0348 AM CST Wed Dec 11 2024 Valid 141200Z - 191200Z ...DISCUSSION... A progressive upper pattern is expected in the extended, with several low-amplitude shortwave troughs forecast to traverse the CONUS. Lead shortwave in this series will likely be over the central Plains on D4/Saturday morning before then moving through the Mid MS Valley by late D4/Saturday and through the OH Valley on D5/Sunday. Another shortwave is expected to follow in the wake of the first, progressing across the Great Basin and Four Corners on D5/Sunday and the southern/central Plains on D6/Monday. This wave may phase with another shortwave moving through central Canada, with resultant troughing extended from the Canadian Prairies into the southern Plains by D6/Monday afternoon. Yet another shortwave is currently progged to drop from the Pacific Northwest/northern CA into the Great Basin late D6/Monday. Guidance varies significantly on the evolution of this wave, and its strength/maturity and location currently have limited predictability. Moisture return is anticipated across the Plains ahead of each of these waves. Enough moisture and buoyancy should exist ahead of the first shortwave to support thunderstorms, as it moves eastward on into the MS Valley on D4/Saturday and through the remainder of the eastern CONUS on D5/Sunday. The most significant moisture return is currently expected ahead of the second shortwave on D5/Sunday and D6/Monday. Thunderstorms are likely as the shortwave and associated cold front interact with this return moisture, although variability within the guidance of the strength and speed of this wave results in differing areas of highest thunderstorm coverage. Some severe appears possible, particularly if the wave is stronger and further south as suggested by the 00Z ECMWF. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0150 AM CST Wed Dec 11 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible Friday afternoon through early Saturday morning from the Middle Texas Coast into the Ozark Plateau. ...Synopsis and Discussion... A shortwave trough is forecast to begin the period over the Four Corners before then continuing eastward across the central Rockies and ending the period over the central Plains. An associated surface low is expected to move quickly northeastward just ahead of this shortwave, progressing from the northeast NM/southeast CO vicinity across KS into the Mid MO Valley. As it does, an attendant cold front will push eastward across the central and southern Plains. Moderate moisture return is anticipated within the strong low to mid-level flow preceding this shortwave and its attendant cold front. Expectation is for low 60s dewpoints to reach north Texas by early Saturday morning, with mid 60s dewpoints remaining confined to the TX Coastal Plain. Mid-level temperatures will be relatively warm, and this modified Gulf moisture is not expected to result in significant buoyancy. Nevertheless, persistent warm-air advection will likely result in elevated thunderstorms with the warm sector extending from the Middle TX Coast into the Ozark Plateau. Stronger vertical shear is anticipated with northward extent, and there is some potential for a few more organized storms capable of small hail across in the eastern OK/northwest AR vicinity. Even so, the overall severe threat is currently too low to introduce any probabilities. ..Mosier.. 12/11/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0150 AM CST Wed Dec 11 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible Friday afternoon through early Saturday morning from the Middle Texas Coast into the Ozark Plateau. ...Synopsis and Discussion... A shortwave trough is forecast to begin the period over the Four Corners before then continuing eastward across the central Rockies and ending the period over the central Plains. An associated surface low is expected to move quickly northeastward just ahead of this shortwave, progressing from the northeast NM/southeast CO vicinity across KS into the Mid MO Valley. As it does, an attendant cold front will push eastward across the central and southern Plains. Moderate moisture return is anticipated within the strong low to mid-level flow preceding this shortwave and its attendant cold front. Expectation is for low 60s dewpoints to reach north Texas by early Saturday morning, with mid 60s dewpoints remaining confined to the TX Coastal Plain. Mid-level temperatures will be relatively warm, and this modified Gulf moisture is not expected to result in significant buoyancy. Nevertheless, persistent warm-air advection will likely result in elevated thunderstorms with the warm sector extending from the Middle TX Coast into the Ozark Plateau. Stronger vertical shear is anticipated with northward extent, and there is some potential for a few more organized storms capable of small hail across in the eastern OK/northwest AR vicinity. Even so, the overall severe threat is currently too low to introduce any probabilities. ..Mosier.. 12/11/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0150 AM CST Wed Dec 11 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible Friday afternoon through early Saturday morning from the Middle Texas Coast into the Ozark Plateau. ...Synopsis and Discussion... A shortwave trough is forecast to begin the period over the Four Corners before then continuing eastward across the central Rockies and ending the period over the central Plains. An associated surface low is expected to move quickly northeastward just ahead of this shortwave, progressing from the northeast NM/southeast CO vicinity across KS into the Mid MO Valley. As it does, an attendant cold front will push eastward across the central and southern Plains. Moderate moisture return is anticipated within the strong low to mid-level flow preceding this shortwave and its attendant cold front. Expectation is for low 60s dewpoints to reach north Texas by early Saturday morning, with mid 60s dewpoints remaining confined to the TX Coastal Plain. Mid-level temperatures will be relatively warm, and this modified Gulf moisture is not expected to result in significant buoyancy. Nevertheless, persistent warm-air advection will likely result in elevated thunderstorms with the warm sector extending from the Middle TX Coast into the Ozark Plateau. Stronger vertical shear is anticipated with northward extent, and there is some potential for a few more organized storms capable of small hail across in the eastern OK/northwest AR vicinity. Even so, the overall severe threat is currently too low to introduce any probabilities. ..Mosier.. 12/11/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0150 AM CST Wed Dec 11 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible Friday afternoon through early Saturday morning from the Middle Texas Coast into the Ozark Plateau. ...Synopsis and Discussion... A shortwave trough is forecast to begin the period over the Four Corners before then continuing eastward across the central Rockies and ending the period over the central Plains. An associated surface low is expected to move quickly northeastward just ahead of this shortwave, progressing from the northeast NM/southeast CO vicinity across KS into the Mid MO Valley. As it does, an attendant cold front will push eastward across the central and southern Plains. Moderate moisture return is anticipated within the strong low to mid-level flow preceding this shortwave and its attendant cold front. Expectation is for low 60s dewpoints to reach north Texas by early Saturday morning, with mid 60s dewpoints remaining confined to the TX Coastal Plain. Mid-level temperatures will be relatively warm, and this modified Gulf moisture is not expected to result in significant buoyancy. Nevertheless, persistent warm-air advection will likely result in elevated thunderstorms with the warm sector extending from the Middle TX Coast into the Ozark Plateau. Stronger vertical shear is anticipated with northward extent, and there is some potential for a few more organized storms capable of small hail across in the eastern OK/northwest AR vicinity. Even so, the overall severe threat is currently too low to introduce any probabilities. ..Mosier.. 12/11/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0150 AM CST Wed Dec 11 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible Friday afternoon through early Saturday morning from the Middle Texas Coast into the Ozark Plateau. ...Synopsis and Discussion... A shortwave trough is forecast to begin the period over the Four Corners before then continuing eastward across the central Rockies and ending the period over the central Plains. An associated surface low is expected to move quickly northeastward just ahead of this shortwave, progressing from the northeast NM/southeast CO vicinity across KS into the Mid MO Valley. As it does, an attendant cold front will push eastward across the central and southern Plains. Moderate moisture return is anticipated within the strong low to mid-level flow preceding this shortwave and its attendant cold front. Expectation is for low 60s dewpoints to reach north Texas by early Saturday morning, with mid 60s dewpoints remaining confined to the TX Coastal Plain. Mid-level temperatures will be relatively warm, and this modified Gulf moisture is not expected to result in significant buoyancy. Nevertheless, persistent warm-air advection will likely result in elevated thunderstorms with the warm sector extending from the Middle TX Coast into the Ozark Plateau. Stronger vertical shear is anticipated with northward extent, and there is some potential for a few more organized storms capable of small hail across in the eastern OK/northwest AR vicinity. Even so, the overall severe threat is currently too low to introduce any probabilities. ..Mosier.. 12/11/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0150 AM CST Wed Dec 11 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible Friday afternoon through early Saturday morning from the Middle Texas Coast into the Ozark Plateau. ...Synopsis and Discussion... A shortwave trough is forecast to begin the period over the Four Corners before then continuing eastward across the central Rockies and ending the period over the central Plains. An associated surface low is expected to move quickly northeastward just ahead of this shortwave, progressing from the northeast NM/southeast CO vicinity across KS into the Mid MO Valley. As it does, an attendant cold front will push eastward across the central and southern Plains. Moderate moisture return is anticipated within the strong low to mid-level flow preceding this shortwave and its attendant cold front. Expectation is for low 60s dewpoints to reach north Texas by early Saturday morning, with mid 60s dewpoints remaining confined to the TX Coastal Plain. Mid-level temperatures will be relatively warm, and this modified Gulf moisture is not expected to result in significant buoyancy. Nevertheless, persistent warm-air advection will likely result in elevated thunderstorms with the warm sector extending from the Middle TX Coast into the Ozark Plateau. Stronger vertical shear is anticipated with northward extent, and there is some potential for a few more organized storms capable of small hail across in the eastern OK/northwest AR vicinity. Even so, the overall severe threat is currently too low to introduce any probabilities. ..Mosier.. 12/11/2024 Read more