Severe Storms

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CST Mon Dec 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF CENTRAL AND SOUTH AL...SOUTHWEST GA...AND THE ADJACENT FL PANHANDLE... ...SUMMARY... Isolated severe thunderstorms are possible across portions of central and south Alabama, southwest Georgia, and the adjacent Florida Panhandle on Tuesday. ...Synopsis... Deep upper troughing is forecast to extend from central CA into the Southwest/northern Mexico Tuesday. This troughing will be anchored by a shortwave trough expected to move from the southern High Plains eastward across the southern Plains and Lower MS Valley. Progression of this shortwave will foster a more neutral tilt to the parent upper troughing while also significantly strengthening the mid-level flow through its eastern periphery. A belt of 100-120 kt 500 mb flow will likely extend from AL into the central Appalachians early Wednesday morning. A surface low initially near the ArkLaMiss region is expected to move quickly northeast toward the upper Ohio Valley, with some guidance showing secondary cyclogenesis later in the period along the trailing cold front that will move across the Southeast. ...Southeast... A moderately moist warm sector will precede the front forecast to move across the region, with dewpoints increasing into the mid 60s by the afternoon across central AL/GA and the FL Panhandle. Modest secondary cyclogenesis appears possible along the front as it moves through central AL and intersects slightly greater returning low-level moisture. Buoyancy will remain modest, mitigated by poor lapse rates and relatively warm profiles, but vertical shear will be strong (i.e. 0-6 km bulk shear greater than 50 kt) and supportive of organization with any deeper, more persistent updrafts. These deeper updrafts appear most probable within the warm sector near the developing secondary surface low (i.e. central/southern AL into southwest GA and the adjacent FL Panhandle) during the late afternoon. Any sustained cells/clusters within this environment could pose a threat of isolated damaging gusts and possibly a tornado. A gradually narrowing warm sector will likely limit the northern and eastern extent of the severe threat, though a strong storm or two cannot be ruled out from north AL/GA into middle/eastern TN. ...GA/north FL in the Carolinas and Outer Banks late Tuesday night into early Wednesday morning... A strong south-southwesterly low-level jet is expected to develop from Georgia through the eastern Carolinas late Tuesday night into Wednesday morning, in response to the intensifying shortwave trough moving into the Southeast. Warm-air advection associated with this jet coupled with strengthening large-scale ascent is expected to result in increasingly broad area of precipitation across the region. Surface-based storms appears unlikely within this environment, but robust wind fields could still support a strong gust or two. Greater low-level moisture may advect into the NC Outer Banks vicinity early Wednesday morning, with low-level and deep-layer shear increasing across the region as well. Any surface-based storms could have some severe potential. However, guidance differs on how far the mid 60s dewpoints penetrate inland, which, given the warm mid-level temperatures, currently limits the predictability of surface-based storms. ..Mosier.. 12/09/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CST Mon Dec 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF CENTRAL AND SOUTH AL...SOUTHWEST GA...AND THE ADJACENT FL PANHANDLE... ...SUMMARY... Isolated severe thunderstorms are possible across portions of central and south Alabama, southwest Georgia, and the adjacent Florida Panhandle on Tuesday. ...Synopsis... Deep upper troughing is forecast to extend from central CA into the Southwest/northern Mexico Tuesday. This troughing will be anchored by a shortwave trough expected to move from the southern High Plains eastward across the southern Plains and Lower MS Valley. Progression of this shortwave will foster a more neutral tilt to the parent upper troughing while also significantly strengthening the mid-level flow through its eastern periphery. A belt of 100-120 kt 500 mb flow will likely extend from AL into the central Appalachians early Wednesday morning. A surface low initially near the ArkLaMiss region is expected to move quickly northeast toward the upper Ohio Valley, with some guidance showing secondary cyclogenesis later in the period along the trailing cold front that will move across the Southeast. ...Southeast... A moderately moist warm sector will precede the front forecast to move across the region, with dewpoints increasing into the mid 60s by the afternoon across central AL/GA and the FL Panhandle. Modest secondary cyclogenesis appears possible along the front as it moves through central AL and intersects slightly greater returning low-level moisture. Buoyancy will remain modest, mitigated by poor lapse rates and relatively warm profiles, but vertical shear will be strong (i.e. 0-6 km bulk shear greater than 50 kt) and supportive of organization with any deeper, more persistent updrafts. These deeper updrafts appear most probable within the warm sector near the developing secondary surface low (i.e. central/southern AL into southwest GA and the adjacent FL Panhandle) during the late afternoon. Any sustained cells/clusters within this environment could pose a threat of isolated damaging gusts and possibly a tornado. A gradually narrowing warm sector will likely limit the northern and eastern extent of the severe threat, though a strong storm or two cannot be ruled out from north AL/GA into middle/eastern TN. ...GA/north FL in the Carolinas and Outer Banks late Tuesday night into early Wednesday morning... A strong south-southwesterly low-level jet is expected to develop from Georgia through the eastern Carolinas late Tuesday night into Wednesday morning, in response to the intensifying shortwave trough moving into the Southeast. Warm-air advection associated with this jet coupled with strengthening large-scale ascent is expected to result in increasingly broad area of precipitation across the region. Surface-based storms appears unlikely within this environment, but robust wind fields could still support a strong gust or two. Greater low-level moisture may advect into the NC Outer Banks vicinity early Wednesday morning, with low-level and deep-layer shear increasing across the region as well. Any surface-based storms could have some severe potential. However, guidance differs on how far the mid 60s dewpoints penetrate inland, which, given the warm mid-level temperatures, currently limits the predictability of surface-based storms. ..Mosier.. 12/09/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CST Mon Dec 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF CENTRAL AND SOUTH AL...SOUTHWEST GA...AND THE ADJACENT FL PANHANDLE... ...SUMMARY... Isolated severe thunderstorms are possible across portions of central and south Alabama, southwest Georgia, and the adjacent Florida Panhandle on Tuesday. ...Synopsis... Deep upper troughing is forecast to extend from central CA into the Southwest/northern Mexico Tuesday. This troughing will be anchored by a shortwave trough expected to move from the southern High Plains eastward across the southern Plains and Lower MS Valley. Progression of this shortwave will foster a more neutral tilt to the parent upper troughing while also significantly strengthening the mid-level flow through its eastern periphery. A belt of 100-120 kt 500 mb flow will likely extend from AL into the central Appalachians early Wednesday morning. A surface low initially near the ArkLaMiss region is expected to move quickly northeast toward the upper Ohio Valley, with some guidance showing secondary cyclogenesis later in the period along the trailing cold front that will move across the Southeast. ...Southeast... A moderately moist warm sector will precede the front forecast to move across the region, with dewpoints increasing into the mid 60s by the afternoon across central AL/GA and the FL Panhandle. Modest secondary cyclogenesis appears possible along the front as it moves through central AL and intersects slightly greater returning low-level moisture. Buoyancy will remain modest, mitigated by poor lapse rates and relatively warm profiles, but vertical shear will be strong (i.e. 0-6 km bulk shear greater than 50 kt) and supportive of organization with any deeper, more persistent updrafts. These deeper updrafts appear most probable within the warm sector near the developing secondary surface low (i.e. central/southern AL into southwest GA and the adjacent FL Panhandle) during the late afternoon. Any sustained cells/clusters within this environment could pose a threat of isolated damaging gusts and possibly a tornado. A gradually narrowing warm sector will likely limit the northern and eastern extent of the severe threat, though a strong storm or two cannot be ruled out from north AL/GA into middle/eastern TN. ...GA/north FL in the Carolinas and Outer Banks late Tuesday night into early Wednesday morning... A strong south-southwesterly low-level jet is expected to develop from Georgia through the eastern Carolinas late Tuesday night into Wednesday morning, in response to the intensifying shortwave trough moving into the Southeast. Warm-air advection associated with this jet coupled with strengthening large-scale ascent is expected to result in increasingly broad area of precipitation across the region. Surface-based storms appears unlikely within this environment, but robust wind fields could still support a strong gust or two. Greater low-level moisture may advect into the NC Outer Banks vicinity early Wednesday morning, with low-level and deep-layer shear increasing across the region as well. Any surface-based storms could have some severe potential. However, guidance differs on how far the mid 60s dewpoints penetrate inland, which, given the warm mid-level temperatures, currently limits the predictability of surface-based storms. ..Mosier.. 12/09/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CST Mon Dec 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF CENTRAL AND SOUTH AL...SOUTHWEST GA...AND THE ADJACENT FL PANHANDLE... ...SUMMARY... Isolated severe thunderstorms are possible across portions of central and south Alabama, southwest Georgia, and the adjacent Florida Panhandle on Tuesday. ...Synopsis... Deep upper troughing is forecast to extend from central CA into the Southwest/northern Mexico Tuesday. This troughing will be anchored by a shortwave trough expected to move from the southern High Plains eastward across the southern Plains and Lower MS Valley. Progression of this shortwave will foster a more neutral tilt to the parent upper troughing while also significantly strengthening the mid-level flow through its eastern periphery. A belt of 100-120 kt 500 mb flow will likely extend from AL into the central Appalachians early Wednesday morning. A surface low initially near the ArkLaMiss region is expected to move quickly northeast toward the upper Ohio Valley, with some guidance showing secondary cyclogenesis later in the period along the trailing cold front that will move across the Southeast. ...Southeast... A moderately moist warm sector will precede the front forecast to move across the region, with dewpoints increasing into the mid 60s by the afternoon across central AL/GA and the FL Panhandle. Modest secondary cyclogenesis appears possible along the front as it moves through central AL and intersects slightly greater returning low-level moisture. Buoyancy will remain modest, mitigated by poor lapse rates and relatively warm profiles, but vertical shear will be strong (i.e. 0-6 km bulk shear greater than 50 kt) and supportive of organization with any deeper, more persistent updrafts. These deeper updrafts appear most probable within the warm sector near the developing secondary surface low (i.e. central/southern AL into southwest GA and the adjacent FL Panhandle) during the late afternoon. Any sustained cells/clusters within this environment could pose a threat of isolated damaging gusts and possibly a tornado. A gradually narrowing warm sector will likely limit the northern and eastern extent of the severe threat, though a strong storm or two cannot be ruled out from north AL/GA into middle/eastern TN. ...GA/north FL in the Carolinas and Outer Banks late Tuesday night into early Wednesday morning... A strong south-southwesterly low-level jet is expected to develop from Georgia through the eastern Carolinas late Tuesday night into Wednesday morning, in response to the intensifying shortwave trough moving into the Southeast. Warm-air advection associated with this jet coupled with strengthening large-scale ascent is expected to result in increasingly broad area of precipitation across the region. Surface-based storms appears unlikely within this environment, but robust wind fields could still support a strong gust or two. Greater low-level moisture may advect into the NC Outer Banks vicinity early Wednesday morning, with low-level and deep-layer shear increasing across the region as well. Any surface-based storms could have some severe potential. However, guidance differs on how far the mid 60s dewpoints penetrate inland, which, given the warm mid-level temperatures, currently limits the predictability of surface-based storms. ..Mosier.. 12/09/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CST Mon Dec 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF CENTRAL AND SOUTH AL...SOUTHWEST GA...AND THE ADJACENT FL PANHANDLE... ...SUMMARY... Isolated severe thunderstorms are possible across portions of central and south Alabama, southwest Georgia, and the adjacent Florida Panhandle on Tuesday. ...Synopsis... Deep upper troughing is forecast to extend from central CA into the Southwest/northern Mexico Tuesday. This troughing will be anchored by a shortwave trough expected to move from the southern High Plains eastward across the southern Plains and Lower MS Valley. Progression of this shortwave will foster a more neutral tilt to the parent upper troughing while also significantly strengthening the mid-level flow through its eastern periphery. A belt of 100-120 kt 500 mb flow will likely extend from AL into the central Appalachians early Wednesday morning. A surface low initially near the ArkLaMiss region is expected to move quickly northeast toward the upper Ohio Valley, with some guidance showing secondary cyclogenesis later in the period along the trailing cold front that will move across the Southeast. ...Southeast... A moderately moist warm sector will precede the front forecast to move across the region, with dewpoints increasing into the mid 60s by the afternoon across central AL/GA and the FL Panhandle. Modest secondary cyclogenesis appears possible along the front as it moves through central AL and intersects slightly greater returning low-level moisture. Buoyancy will remain modest, mitigated by poor lapse rates and relatively warm profiles, but vertical shear will be strong (i.e. 0-6 km bulk shear greater than 50 kt) and supportive of organization with any deeper, more persistent updrafts. These deeper updrafts appear most probable within the warm sector near the developing secondary surface low (i.e. central/southern AL into southwest GA and the adjacent FL Panhandle) during the late afternoon. Any sustained cells/clusters within this environment could pose a threat of isolated damaging gusts and possibly a tornado. A gradually narrowing warm sector will likely limit the northern and eastern extent of the severe threat, though a strong storm or two cannot be ruled out from north AL/GA into middle/eastern TN. ...GA/north FL in the Carolinas and Outer Banks late Tuesday night into early Wednesday morning... A strong south-southwesterly low-level jet is expected to develop from Georgia through the eastern Carolinas late Tuesday night into Wednesday morning, in response to the intensifying shortwave trough moving into the Southeast. Warm-air advection associated with this jet coupled with strengthening large-scale ascent is expected to result in increasingly broad area of precipitation across the region. Surface-based storms appears unlikely within this environment, but robust wind fields could still support a strong gust or two. Greater low-level moisture may advect into the NC Outer Banks vicinity early Wednesday morning, with low-level and deep-layer shear increasing across the region as well. Any surface-based storms could have some severe potential. However, guidance differs on how far the mid 60s dewpoints penetrate inland, which, given the warm mid-level temperatures, currently limits the predictability of surface-based storms. ..Mosier.. 12/09/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CST Mon Dec 09 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF CENTRAL AND SOUTH AL...SOUTHWEST GA...AND THE ADJACENT FL PANHANDLE... ...SUMMARY... Isolated severe thunderstorms are possible across portions of central and south Alabama, southwest Georgia, and the adjacent Florida Panhandle on Tuesday. ...Synopsis... Deep upper troughing is forecast to extend from central CA into the Southwest/northern Mexico Tuesday. This troughing will be anchored by a shortwave trough expected to move from the southern High Plains eastward across the southern Plains and Lower MS Valley. Progression of this shortwave will foster a more neutral tilt to the parent upper troughing while also significantly strengthening the mid-level flow through its eastern periphery. A belt of 100-120 kt 500 mb flow will likely extend from AL into the central Appalachians early Wednesday morning. A surface low initially near the ArkLaMiss region is expected to move quickly northeast toward the upper Ohio Valley, with some guidance showing secondary cyclogenesis later in the period along the trailing cold front that will move across the Southeast. ...Southeast... A moderately moist warm sector will precede the front forecast to move across the region, with dewpoints increasing into the mid 60s by the afternoon across central AL/GA and the FL Panhandle. Modest secondary cyclogenesis appears possible along the front as it moves through central AL and intersects slightly greater returning low-level moisture. Buoyancy will remain modest, mitigated by poor lapse rates and relatively warm profiles, but vertical shear will be strong (i.e. 0-6 km bulk shear greater than 50 kt) and supportive of organization with any deeper, more persistent updrafts. These deeper updrafts appear most probable within the warm sector near the developing secondary surface low (i.e. central/southern AL into southwest GA and the adjacent FL Panhandle) during the late afternoon. Any sustained cells/clusters within this environment could pose a threat of isolated damaging gusts and possibly a tornado. A gradually narrowing warm sector will likely limit the northern and eastern extent of the severe threat, though a strong storm or two cannot be ruled out from north AL/GA into middle/eastern TN. ...GA/north FL in the Carolinas and Outer Banks late Tuesday night into early Wednesday morning... A strong south-southwesterly low-level jet is expected to develop from Georgia through the eastern Carolinas late Tuesday night into Wednesday morning, in response to the intensifying shortwave trough moving into the Southeast. Warm-air advection associated with this jet coupled with strengthening large-scale ascent is expected to result in increasingly broad area of precipitation across the region. Surface-based storms appears unlikely within this environment, but robust wind fields could still support a strong gust or two. Greater low-level moisture may advect into the NC Outer Banks vicinity early Wednesday morning, with low-level and deep-layer shear increasing across the region as well. Any surface-based storms could have some severe potential. However, guidance differs on how far the mid 60s dewpoints penetrate inland, which, given the warm mid-level temperatures, currently limits the predictability of surface-based storms. ..Mosier.. 12/09/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1150 PM CST Sun Dec 08 2024 Valid 091200Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the Lower Mississippi Valley into much of the Southeast States today through early Tuesday. The probability for severe thunderstorms appears low. ...Synopsis... A weakening shortwave trough will quickly progress eastward across the lower OH river valley early this morning, and is forecast to exit off the East Coast by afternoon. In its wake, a more amplified upper wave over the Rockies will continue to shift east, resulting in broad surface pressure falls across the Plains along and ahead of a southeastward migrating cold front. This low-level mass response, while weak, will be sufficient to maintain a southerly flow regime across the lower MS river valley that will continue to advect a warm/moist air mass inland through the next 24 hours. The persistent warm advection regime over the central Gulf coast will maintain isolated thunderstorm chances through the day. Despite 40-50 knot mid-level flow, weak low to mid-level lapse rates, sampled well by 00 UTC soundings, will modulate updraft intensities and the propensity for organized convection for much of the day. The southeastward-moving cold front is forecast to reach the lower MS river valley during the overnight hours tonight. Thunderstorm chances will likely increase between 06-12 UTC as this boundary impinges on a higher theta-e air mass overspreading southeast LA into southern MS. By this time, low-level moisture advection should be sufficient to mitigate the deleterious effects of nocturnal cooling to some degree and support surface-based convection. However, the overall weak synoptic ascent over the region, combined with limited lapse-rate advection, may not provide sufficient destabilization for robust deep convection despite improving low-level thermodynamics. Nonetheless, veering in the lowest 1-2 km may support weakly rotating shallow convection. Consideration was given for low-end tornado probabilities to address this nocturnal concern; however, latest CAM ensemble guidance generally shows a very weak convective signal (aside from the typically bullish FV3 members), which limits confidence in the overall threat. ..Moore.. 12/09/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1150 PM CST Sun Dec 08 2024 Valid 091200Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the Lower Mississippi Valley into much of the Southeast States today through early Tuesday. The probability for severe thunderstorms appears low. ...Synopsis... A weakening shortwave trough will quickly progress eastward across the lower OH river valley early this morning, and is forecast to exit off the East Coast by afternoon. In its wake, a more amplified upper wave over the Rockies will continue to shift east, resulting in broad surface pressure falls across the Plains along and ahead of a southeastward migrating cold front. This low-level mass response, while weak, will be sufficient to maintain a southerly flow regime across the lower MS river valley that will continue to advect a warm/moist air mass inland through the next 24 hours. The persistent warm advection regime over the central Gulf coast will maintain isolated thunderstorm chances through the day. Despite 40-50 knot mid-level flow, weak low to mid-level lapse rates, sampled well by 00 UTC soundings, will modulate updraft intensities and the propensity for organized convection for much of the day. The southeastward-moving cold front is forecast to reach the lower MS river valley during the overnight hours tonight. Thunderstorm chances will likely increase between 06-12 UTC as this boundary impinges on a higher theta-e air mass overspreading southeast LA into southern MS. By this time, low-level moisture advection should be sufficient to mitigate the deleterious effects of nocturnal cooling to some degree and support surface-based convection. However, the overall weak synoptic ascent over the region, combined with limited lapse-rate advection, may not provide sufficient destabilization for robust deep convection despite improving low-level thermodynamics. Nonetheless, veering in the lowest 1-2 km may support weakly rotating shallow convection. Consideration was given for low-end tornado probabilities to address this nocturnal concern; however, latest CAM ensemble guidance generally shows a very weak convective signal (aside from the typically bullish FV3 members), which limits confidence in the overall threat. ..Moore.. 12/09/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1150 PM CST Sun Dec 08 2024 Valid 091200Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the Lower Mississippi Valley into much of the Southeast States today through early Tuesday. The probability for severe thunderstorms appears low. ...Synopsis... A weakening shortwave trough will quickly progress eastward across the lower OH river valley early this morning, and is forecast to exit off the East Coast by afternoon. In its wake, a more amplified upper wave over the Rockies will continue to shift east, resulting in broad surface pressure falls across the Plains along and ahead of a southeastward migrating cold front. This low-level mass response, while weak, will be sufficient to maintain a southerly flow regime across the lower MS river valley that will continue to advect a warm/moist air mass inland through the next 24 hours. The persistent warm advection regime over the central Gulf coast will maintain isolated thunderstorm chances through the day. Despite 40-50 knot mid-level flow, weak low to mid-level lapse rates, sampled well by 00 UTC soundings, will modulate updraft intensities and the propensity for organized convection for much of the day. The southeastward-moving cold front is forecast to reach the lower MS river valley during the overnight hours tonight. Thunderstorm chances will likely increase between 06-12 UTC as this boundary impinges on a higher theta-e air mass overspreading southeast LA into southern MS. By this time, low-level moisture advection should be sufficient to mitigate the deleterious effects of nocturnal cooling to some degree and support surface-based convection. However, the overall weak synoptic ascent over the region, combined with limited lapse-rate advection, may not provide sufficient destabilization for robust deep convection despite improving low-level thermodynamics. Nonetheless, veering in the lowest 1-2 km may support weakly rotating shallow convection. Consideration was given for low-end tornado probabilities to address this nocturnal concern; however, latest CAM ensemble guidance generally shows a very weak convective signal (aside from the typically bullish FV3 members), which limits confidence in the overall threat. ..Moore.. 12/09/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1150 PM CST Sun Dec 08 2024 Valid 091200Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the Lower Mississippi Valley into much of the Southeast States today through early Tuesday. The probability for severe thunderstorms appears low. ...Synopsis... A weakening shortwave trough will quickly progress eastward across the lower OH river valley early this morning, and is forecast to exit off the East Coast by afternoon. In its wake, a more amplified upper wave over the Rockies will continue to shift east, resulting in broad surface pressure falls across the Plains along and ahead of a southeastward migrating cold front. This low-level mass response, while weak, will be sufficient to maintain a southerly flow regime across the lower MS river valley that will continue to advect a warm/moist air mass inland through the next 24 hours. The persistent warm advection regime over the central Gulf coast will maintain isolated thunderstorm chances through the day. Despite 40-50 knot mid-level flow, weak low to mid-level lapse rates, sampled well by 00 UTC soundings, will modulate updraft intensities and the propensity for organized convection for much of the day. The southeastward-moving cold front is forecast to reach the lower MS river valley during the overnight hours tonight. Thunderstorm chances will likely increase between 06-12 UTC as this boundary impinges on a higher theta-e air mass overspreading southeast LA into southern MS. By this time, low-level moisture advection should be sufficient to mitigate the deleterious effects of nocturnal cooling to some degree and support surface-based convection. However, the overall weak synoptic ascent over the region, combined with limited lapse-rate advection, may not provide sufficient destabilization for robust deep convection despite improving low-level thermodynamics. Nonetheless, veering in the lowest 1-2 km may support weakly rotating shallow convection. Consideration was given for low-end tornado probabilities to address this nocturnal concern; however, latest CAM ensemble guidance generally shows a very weak convective signal (aside from the typically bullish FV3 members), which limits confidence in the overall threat. ..Moore.. 12/09/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1150 PM CST Sun Dec 08 2024 Valid 091200Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the Lower Mississippi Valley into much of the Southeast States today through early Tuesday. The probability for severe thunderstorms appears low. ...Synopsis... A weakening shortwave trough will quickly progress eastward across the lower OH river valley early this morning, and is forecast to exit off the East Coast by afternoon. In its wake, a more amplified upper wave over the Rockies will continue to shift east, resulting in broad surface pressure falls across the Plains along and ahead of a southeastward migrating cold front. This low-level mass response, while weak, will be sufficient to maintain a southerly flow regime across the lower MS river valley that will continue to advect a warm/moist air mass inland through the next 24 hours. The persistent warm advection regime over the central Gulf coast will maintain isolated thunderstorm chances through the day. Despite 40-50 knot mid-level flow, weak low to mid-level lapse rates, sampled well by 00 UTC soundings, will modulate updraft intensities and the propensity for organized convection for much of the day. The southeastward-moving cold front is forecast to reach the lower MS river valley during the overnight hours tonight. Thunderstorm chances will likely increase between 06-12 UTC as this boundary impinges on a higher theta-e air mass overspreading southeast LA into southern MS. By this time, low-level moisture advection should be sufficient to mitigate the deleterious effects of nocturnal cooling to some degree and support surface-based convection. However, the overall weak synoptic ascent over the region, combined with limited lapse-rate advection, may not provide sufficient destabilization for robust deep convection despite improving low-level thermodynamics. Nonetheless, veering in the lowest 1-2 km may support weakly rotating shallow convection. Consideration was given for low-end tornado probabilities to address this nocturnal concern; however, latest CAM ensemble guidance generally shows a very weak convective signal (aside from the typically bullish FV3 members), which limits confidence in the overall threat. ..Moore.. 12/09/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1150 PM CST Sun Dec 08 2024 Valid 091200Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the Lower Mississippi Valley into much of the Southeast States today through early Tuesday. The probability for severe thunderstorms appears low. ...Synopsis... A weakening shortwave trough will quickly progress eastward across the lower OH river valley early this morning, and is forecast to exit off the East Coast by afternoon. In its wake, a more amplified upper wave over the Rockies will continue to shift east, resulting in broad surface pressure falls across the Plains along and ahead of a southeastward migrating cold front. This low-level mass response, while weak, will be sufficient to maintain a southerly flow regime across the lower MS river valley that will continue to advect a warm/moist air mass inland through the next 24 hours. The persistent warm advection regime over the central Gulf coast will maintain isolated thunderstorm chances through the day. Despite 40-50 knot mid-level flow, weak low to mid-level lapse rates, sampled well by 00 UTC soundings, will modulate updraft intensities and the propensity for organized convection for much of the day. The southeastward-moving cold front is forecast to reach the lower MS river valley during the overnight hours tonight. Thunderstorm chances will likely increase between 06-12 UTC as this boundary impinges on a higher theta-e air mass overspreading southeast LA into southern MS. By this time, low-level moisture advection should be sufficient to mitigate the deleterious effects of nocturnal cooling to some degree and support surface-based convection. However, the overall weak synoptic ascent over the region, combined with limited lapse-rate advection, may not provide sufficient destabilization for robust deep convection despite improving low-level thermodynamics. Nonetheless, veering in the lowest 1-2 km may support weakly rotating shallow convection. Consideration was given for low-end tornado probabilities to address this nocturnal concern; however, latest CAM ensemble guidance generally shows a very weak convective signal (aside from the typically bullish FV3 members), which limits confidence in the overall threat. ..Moore.. 12/09/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1150 PM CST Sun Dec 08 2024 Valid 091200Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the Lower Mississippi Valley into much of the Southeast States today through early Tuesday. The probability for severe thunderstorms appears low. ...Synopsis... A weakening shortwave trough will quickly progress eastward across the lower OH river valley early this morning, and is forecast to exit off the East Coast by afternoon. In its wake, a more amplified upper wave over the Rockies will continue to shift east, resulting in broad surface pressure falls across the Plains along and ahead of a southeastward migrating cold front. This low-level mass response, while weak, will be sufficient to maintain a southerly flow regime across the lower MS river valley that will continue to advect a warm/moist air mass inland through the next 24 hours. The persistent warm advection regime over the central Gulf coast will maintain isolated thunderstorm chances through the day. Despite 40-50 knot mid-level flow, weak low to mid-level lapse rates, sampled well by 00 UTC soundings, will modulate updraft intensities and the propensity for organized convection for much of the day. The southeastward-moving cold front is forecast to reach the lower MS river valley during the overnight hours tonight. Thunderstorm chances will likely increase between 06-12 UTC as this boundary impinges on a higher theta-e air mass overspreading southeast LA into southern MS. By this time, low-level moisture advection should be sufficient to mitigate the deleterious effects of nocturnal cooling to some degree and support surface-based convection. However, the overall weak synoptic ascent over the region, combined with limited lapse-rate advection, may not provide sufficient destabilization for robust deep convection despite improving low-level thermodynamics. Nonetheless, veering in the lowest 1-2 km may support weakly rotating shallow convection. Consideration was given for low-end tornado probabilities to address this nocturnal concern; however, latest CAM ensemble guidance generally shows a very weak convective signal (aside from the typically bullish FV3 members), which limits confidence in the overall threat. ..Moore.. 12/09/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0651 PM CST Sun Dec 08 2024 Valid 090100Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis... A broad stratiform rain shield persists across much of the mid to lower MS River Valley, spreading into the Southeast states. 00 UTC soundings from the region show minimal buoyancy, but low to mid-level warm advection, coupled with weak deep ascent/mid-level cooling, will continue to promote the potential for sporadic lightning flashes through the overnight/early morning hours. Weak convection has been noted across parts of eastern KS and into MO in the vicinity of the mid-level vorticity maximum where temperatures aloft are relatively cooler and ascent is somewhat stronger. Although model guidance appears to be overzealous in depicting MUCAPE based on the observed 00 UTC SGF sounding, weak convective towers noted in IR imagery in proximity to the vorticity maximum, along with a weak signal for CI across eastern MO/western IL, prompted a northward expansion of the thunder area (though the probability of lightning remains fairly low at around 10%). ..Moore.. 12/09/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0651 PM CST Sun Dec 08 2024 Valid 090100Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis... A broad stratiform rain shield persists across much of the mid to lower MS River Valley, spreading into the Southeast states. 00 UTC soundings from the region show minimal buoyancy, but low to mid-level warm advection, coupled with weak deep ascent/mid-level cooling, will continue to promote the potential for sporadic lightning flashes through the overnight/early morning hours. Weak convection has been noted across parts of eastern KS and into MO in the vicinity of the mid-level vorticity maximum where temperatures aloft are relatively cooler and ascent is somewhat stronger. Although model guidance appears to be overzealous in depicting MUCAPE based on the observed 00 UTC SGF sounding, weak convective towers noted in IR imagery in proximity to the vorticity maximum, along with a weak signal for CI across eastern MO/western IL, prompted a northward expansion of the thunder area (though the probability of lightning remains fairly low at around 10%). ..Moore.. 12/09/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0651 PM CST Sun Dec 08 2024 Valid 090100Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis... A broad stratiform rain shield persists across much of the mid to lower MS River Valley, spreading into the Southeast states. 00 UTC soundings from the region show minimal buoyancy, but low to mid-level warm advection, coupled with weak deep ascent/mid-level cooling, will continue to promote the potential for sporadic lightning flashes through the overnight/early morning hours. Weak convection has been noted across parts of eastern KS and into MO in the vicinity of the mid-level vorticity maximum where temperatures aloft are relatively cooler and ascent is somewhat stronger. Although model guidance appears to be overzealous in depicting MUCAPE based on the observed 00 UTC SGF sounding, weak convective towers noted in IR imagery in proximity to the vorticity maximum, along with a weak signal for CI across eastern MO/western IL, prompted a northward expansion of the thunder area (though the probability of lightning remains fairly low at around 10%). ..Moore.. 12/09/2024 Read more

No watches are valid as of Sun Dec 8 22:34:02 UTC 2024.

No Mesoscale Discussions are in effect as of Sun Dec 8 22:34:02 UTC 2024.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0332 PM CST Sun Dec 08 2024 Valid 101200Z - 161200Z ...Days 3-4/Tuesday-Wednesday - Southern California... Large-scale trough amplification is forecast over the western CONUS on Monday. This in combination with an anonymously strong surface high pressure over the Intermountain West will tighten offshore pressure gradients across southern CA (LAX-DAG gradient peaking around -8 to -9 mb). This pattern will favor critical fire-weather conditions across portions of Ventura and Los Angeles Counties in southern CA, given increasingly dry/receptive fuels. Critical conditions are expected to increase in coverage late D2 - Monday and continue into late D3 Tuesday - D4 Wednesday. Pressure gradients are forecast to peak on D3 - Tuesday, and 70-percent Critical probabilities have been maintained with this outlook. The 40 percent region was expanded to include mountain zones in San Luis Obispo County. Areas of Extremely Critical conditions are likely Tuesday morning and afternoon where single digit humidity overlaps stronger winds (gusting 40 - 50 mph up to 60-70+ mph in the mountains) in favored downslope regions of the mountains and foothills in Ventura and Los Angeles Counties. Fire weather concerns will linger into D4 - Wednesday morning before gradients begin to gradually weaken through the day. Given the potential for a long period of Critical conditions prior and forecast for continued single digit humidity, a 40 percent delineation was maintained for continuance of this threat overnight Tuesday into the late morning Wednesday. As the western trough ejects across the Plains D3/Tuesday into D4 - Wednesday, periods of dry/windy conditions are expected across the High/Southern Plains, however, fuels do not appear supportive of large-fire potential at this time. ERC forecasts do indicate fuels will dry, particularly across western Texas into eastern New Mexico, but largely remain below Critical thresholds. ..Thornton.. 12/08/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0332 PM CST Sun Dec 08 2024 Valid 101200Z - 161200Z ...Days 3-4/Tuesday-Wednesday - Southern California... Large-scale trough amplification is forecast over the western CONUS on Monday. This in combination with an anonymously strong surface high pressure over the Intermountain West will tighten offshore pressure gradients across southern CA (LAX-DAG gradient peaking around -8 to -9 mb). This pattern will favor critical fire-weather conditions across portions of Ventura and Los Angeles Counties in southern CA, given increasingly dry/receptive fuels. Critical conditions are expected to increase in coverage late D2 - Monday and continue into late D3 Tuesday - D4 Wednesday. Pressure gradients are forecast to peak on D3 - Tuesday, and 70-percent Critical probabilities have been maintained with this outlook. The 40 percent region was expanded to include mountain zones in San Luis Obispo County. Areas of Extremely Critical conditions are likely Tuesday morning and afternoon where single digit humidity overlaps stronger winds (gusting 40 - 50 mph up to 60-70+ mph in the mountains) in favored downslope regions of the mountains and foothills in Ventura and Los Angeles Counties. Fire weather concerns will linger into D4 - Wednesday morning before gradients begin to gradually weaken through the day. Given the potential for a long period of Critical conditions prior and forecast for continued single digit humidity, a 40 percent delineation was maintained for continuance of this threat overnight Tuesday into the late morning Wednesday. As the western trough ejects across the Plains D3/Tuesday into D4 - Wednesday, periods of dry/windy conditions are expected across the High/Southern Plains, however, fuels do not appear supportive of large-fire potential at this time. ERC forecasts do indicate fuels will dry, particularly across western Texas into eastern New Mexico, but largely remain below Critical thresholds. ..Thornton.. 12/08/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more