Severe Storms

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0152 AM CST Tue Dec 17 2024 Valid 191200Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Thursday. ...Synopsis... An upper trough extending along the Atlantic coast into the eastern Gulf of Mexico will shift east across FL and moving offshore early in the forecast period. Meanwhile, a shortwave trough over the northern/central Plains will deepen and pivot east, maintaining a mean upper trough over the eastern U.S. through the period. A surface cold front will be located over north-central FL Thursday morning, and quickly develop south through the day. Weak instability is forecast ahead of the front across portions of the southeast FL Peninsula, supporting isolated thunderstorms. Poor midlevel lapse rates and very weak low and midlevel flow will preclude severe thunderstorm potential. ..Leitman.. 12/17/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0152 AM CST Tue Dec 17 2024 Valid 191200Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Thursday. ...Synopsis... An upper trough extending along the Atlantic coast into the eastern Gulf of Mexico will shift east across FL and moving offshore early in the forecast period. Meanwhile, a shortwave trough over the northern/central Plains will deepen and pivot east, maintaining a mean upper trough over the eastern U.S. through the period. A surface cold front will be located over north-central FL Thursday morning, and quickly develop south through the day. Weak instability is forecast ahead of the front across portions of the southeast FL Peninsula, supporting isolated thunderstorms. Poor midlevel lapse rates and very weak low and midlevel flow will preclude severe thunderstorm potential. ..Leitman.. 12/17/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0152 AM CST Tue Dec 17 2024 Valid 191200Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Thursday. ...Synopsis... An upper trough extending along the Atlantic coast into the eastern Gulf of Mexico will shift east across FL and moving offshore early in the forecast period. Meanwhile, a shortwave trough over the northern/central Plains will deepen and pivot east, maintaining a mean upper trough over the eastern U.S. through the period. A surface cold front will be located over north-central FL Thursday morning, and quickly develop south through the day. Weak instability is forecast ahead of the front across portions of the southeast FL Peninsula, supporting isolated thunderstorms. Poor midlevel lapse rates and very weak low and midlevel flow will preclude severe thunderstorm potential. ..Leitman.. 12/17/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0152 AM CST Tue Dec 17 2024 Valid 191200Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Thursday. ...Synopsis... An upper trough extending along the Atlantic coast into the eastern Gulf of Mexico will shift east across FL and moving offshore early in the forecast period. Meanwhile, a shortwave trough over the northern/central Plains will deepen and pivot east, maintaining a mean upper trough over the eastern U.S. through the period. A surface cold front will be located over north-central FL Thursday morning, and quickly develop south through the day. Weak instability is forecast ahead of the front across portions of the southeast FL Peninsula, supporting isolated thunderstorms. Poor midlevel lapse rates and very weak low and midlevel flow will preclude severe thunderstorm potential. ..Leitman.. 12/17/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CST Tue Dec 17 2024 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the lower Ohio Valley southwest into northeast/central Texas early on Wednesday and across the Southeast, Carolinas, and Florida Wednesday afternoon and evening. ...Synopsis... A positively tilted upper trough will develop east across the eastern U.S. on Wednesday. Moderate mid/upper level southwesterly flow ahead of the trough will overspread the OH/TN Valleys into the Carolinas and Mid-Atlantic regions. At the surface, a cold front will extend from southern OH to southeast AR to central TX at the beginning of the period. This front will develop southeast across the Southeast and Mid-Atlantic, mostly moving offshore from the Gulf and Atlantic coasts by Thursday morning. ...Northeast TX to the TN Valley... Showers and elevated thunderstorms will likely be ongoing near the surface cold front Wednesday morning. Forecast soundings show poor low-level lapse rates and little surface-based instability. However, up to 500 J/kg MUCAPE will be present, courtesy of cool midlevel temperatures and modest midlevel lapse rates. Deep-layer flow is forecast to remain mostly unidirectional and parallel to the front, suggesting convective undercutting by the boundary/outflows. While some briefly organized structure may persist the first hour or two of the forecast period, convection is expected to rapidly decrease in intensity with southeast extent across the TN Valley/Gulf Coast states. This is largely due to more modest boundary-layer moisture and weakening vertical shear across MS/AL. ...FL/GA/Carolinas... Isentropic ascent ahead of the approaching upper trough/surface front will increase across the region through day. However, large-scale ascent will remain weak until late, with the vorticity maxima trailing well behind the surface front. Nevertheless, showers and isolated thunderstorms will be possible within the low-level warm-advection regime, especially during the afternoon/early evening. Forecast guidance varies in the depiction of the low-level thermodynamics and degree of destabilization. Though some support for an organized storm or two is plausible, given around 750-1000 J/kg MLCAPE and effective shear magnitudes around 20-30 kt. While a strong storm could produce gusty winds or even small hail (given somewhat elongated/straight hodographs and cool midlevel temps), forecast confidence regarding severe potential remains fairly low. Will refrain from introducing low-end/Marginal (level 1 of 5) risk probabilities at this time, though an outlook area may be required in subsequent outlooks. ..Leitman.. 12/17/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CST Tue Dec 17 2024 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the lower Ohio Valley southwest into northeast/central Texas early on Wednesday and across the Southeast, Carolinas, and Florida Wednesday afternoon and evening. ...Synopsis... A positively tilted upper trough will develop east across the eastern U.S. on Wednesday. Moderate mid/upper level southwesterly flow ahead of the trough will overspread the OH/TN Valleys into the Carolinas and Mid-Atlantic regions. At the surface, a cold front will extend from southern OH to southeast AR to central TX at the beginning of the period. This front will develop southeast across the Southeast and Mid-Atlantic, mostly moving offshore from the Gulf and Atlantic coasts by Thursday morning. ...Northeast TX to the TN Valley... Showers and elevated thunderstorms will likely be ongoing near the surface cold front Wednesday morning. Forecast soundings show poor low-level lapse rates and little surface-based instability. However, up to 500 J/kg MUCAPE will be present, courtesy of cool midlevel temperatures and modest midlevel lapse rates. Deep-layer flow is forecast to remain mostly unidirectional and parallel to the front, suggesting convective undercutting by the boundary/outflows. While some briefly organized structure may persist the first hour or two of the forecast period, convection is expected to rapidly decrease in intensity with southeast extent across the TN Valley/Gulf Coast states. This is largely due to more modest boundary-layer moisture and weakening vertical shear across MS/AL. ...FL/GA/Carolinas... Isentropic ascent ahead of the approaching upper trough/surface front will increase across the region through day. However, large-scale ascent will remain weak until late, with the vorticity maxima trailing well behind the surface front. Nevertheless, showers and isolated thunderstorms will be possible within the low-level warm-advection regime, especially during the afternoon/early evening. Forecast guidance varies in the depiction of the low-level thermodynamics and degree of destabilization. Though some support for an organized storm or two is plausible, given around 750-1000 J/kg MLCAPE and effective shear magnitudes around 20-30 kt. While a strong storm could produce gusty winds or even small hail (given somewhat elongated/straight hodographs and cool midlevel temps), forecast confidence regarding severe potential remains fairly low. Will refrain from introducing low-end/Marginal (level 1 of 5) risk probabilities at this time, though an outlook area may be required in subsequent outlooks. ..Leitman.. 12/17/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CST Tue Dec 17 2024 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the lower Ohio Valley southwest into northeast/central Texas early on Wednesday and across the Southeast, Carolinas, and Florida Wednesday afternoon and evening. ...Synopsis... A positively tilted upper trough will develop east across the eastern U.S. on Wednesday. Moderate mid/upper level southwesterly flow ahead of the trough will overspread the OH/TN Valleys into the Carolinas and Mid-Atlantic regions. At the surface, a cold front will extend from southern OH to southeast AR to central TX at the beginning of the period. This front will develop southeast across the Southeast and Mid-Atlantic, mostly moving offshore from the Gulf and Atlantic coasts by Thursday morning. ...Northeast TX to the TN Valley... Showers and elevated thunderstorms will likely be ongoing near the surface cold front Wednesday morning. Forecast soundings show poor low-level lapse rates and little surface-based instability. However, up to 500 J/kg MUCAPE will be present, courtesy of cool midlevel temperatures and modest midlevel lapse rates. Deep-layer flow is forecast to remain mostly unidirectional and parallel to the front, suggesting convective undercutting by the boundary/outflows. While some briefly organized structure may persist the first hour or two of the forecast period, convection is expected to rapidly decrease in intensity with southeast extent across the TN Valley/Gulf Coast states. This is largely due to more modest boundary-layer moisture and weakening vertical shear across MS/AL. ...FL/GA/Carolinas... Isentropic ascent ahead of the approaching upper trough/surface front will increase across the region through day. However, large-scale ascent will remain weak until late, with the vorticity maxima trailing well behind the surface front. Nevertheless, showers and isolated thunderstorms will be possible within the low-level warm-advection regime, especially during the afternoon/early evening. Forecast guidance varies in the depiction of the low-level thermodynamics and degree of destabilization. Though some support for an organized storm or two is plausible, given around 750-1000 J/kg MLCAPE and effective shear magnitudes around 20-30 kt. While a strong storm could produce gusty winds or even small hail (given somewhat elongated/straight hodographs and cool midlevel temps), forecast confidence regarding severe potential remains fairly low. Will refrain from introducing low-end/Marginal (level 1 of 5) risk probabilities at this time, though an outlook area may be required in subsequent outlooks. ..Leitman.. 12/17/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CST Tue Dec 17 2024 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the lower Ohio Valley southwest into northeast/central Texas early on Wednesday and across the Southeast, Carolinas, and Florida Wednesday afternoon and evening. ...Synopsis... A positively tilted upper trough will develop east across the eastern U.S. on Wednesday. Moderate mid/upper level southwesterly flow ahead of the trough will overspread the OH/TN Valleys into the Carolinas and Mid-Atlantic regions. At the surface, a cold front will extend from southern OH to southeast AR to central TX at the beginning of the period. This front will develop southeast across the Southeast and Mid-Atlantic, mostly moving offshore from the Gulf and Atlantic coasts by Thursday morning. ...Northeast TX to the TN Valley... Showers and elevated thunderstorms will likely be ongoing near the surface cold front Wednesday morning. Forecast soundings show poor low-level lapse rates and little surface-based instability. However, up to 500 J/kg MUCAPE will be present, courtesy of cool midlevel temperatures and modest midlevel lapse rates. Deep-layer flow is forecast to remain mostly unidirectional and parallel to the front, suggesting convective undercutting by the boundary/outflows. While some briefly organized structure may persist the first hour or two of the forecast period, convection is expected to rapidly decrease in intensity with southeast extent across the TN Valley/Gulf Coast states. This is largely due to more modest boundary-layer moisture and weakening vertical shear across MS/AL. ...FL/GA/Carolinas... Isentropic ascent ahead of the approaching upper trough/surface front will increase across the region through day. However, large-scale ascent will remain weak until late, with the vorticity maxima trailing well behind the surface front. Nevertheless, showers and isolated thunderstorms will be possible within the low-level warm-advection regime, especially during the afternoon/early evening. Forecast guidance varies in the depiction of the low-level thermodynamics and degree of destabilization. Though some support for an organized storm or two is plausible, given around 750-1000 J/kg MLCAPE and effective shear magnitudes around 20-30 kt. While a strong storm could produce gusty winds or even small hail (given somewhat elongated/straight hodographs and cool midlevel temps), forecast confidence regarding severe potential remains fairly low. Will refrain from introducing low-end/Marginal (level 1 of 5) risk probabilities at this time, though an outlook area may be required in subsequent outlooks. ..Leitman.. 12/17/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CST Tue Dec 17 2024 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible from the lower Ohio Valley southwest into northeast/central Texas early on Wednesday and across the Southeast, Carolinas, and Florida Wednesday afternoon and evening. ...Synopsis... A positively tilted upper trough will develop east across the eastern U.S. on Wednesday. Moderate mid/upper level southwesterly flow ahead of the trough will overspread the OH/TN Valleys into the Carolinas and Mid-Atlantic regions. At the surface, a cold front will extend from southern OH to southeast AR to central TX at the beginning of the period. This front will develop southeast across the Southeast and Mid-Atlantic, mostly moving offshore from the Gulf and Atlantic coasts by Thursday morning. ...Northeast TX to the TN Valley... Showers and elevated thunderstorms will likely be ongoing near the surface cold front Wednesday morning. Forecast soundings show poor low-level lapse rates and little surface-based instability. However, up to 500 J/kg MUCAPE will be present, courtesy of cool midlevel temperatures and modest midlevel lapse rates. Deep-layer flow is forecast to remain mostly unidirectional and parallel to the front, suggesting convective undercutting by the boundary/outflows. While some briefly organized structure may persist the first hour or two of the forecast period, convection is expected to rapidly decrease in intensity with southeast extent across the TN Valley/Gulf Coast states. This is largely due to more modest boundary-layer moisture and weakening vertical shear across MS/AL. ...FL/GA/Carolinas... Isentropic ascent ahead of the approaching upper trough/surface front will increase across the region through day. However, large-scale ascent will remain weak until late, with the vorticity maxima trailing well behind the surface front. Nevertheless, showers and isolated thunderstorms will be possible within the low-level warm-advection regime, especially during the afternoon/early evening. Forecast guidance varies in the depiction of the low-level thermodynamics and degree of destabilization. Though some support for an organized storm or two is plausible, given around 750-1000 J/kg MLCAPE and effective shear magnitudes around 20-30 kt. While a strong storm could produce gusty winds or even small hail (given somewhat elongated/straight hodographs and cool midlevel temps), forecast confidence regarding severe potential remains fairly low. Will refrain from introducing low-end/Marginal (level 1 of 5) risk probabilities at this time, though an outlook area may be required in subsequent outlooks. ..Leitman.. 12/17/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1145 PM CST Mon Dec 16 2024 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE MID-SOUTH... ...SUMMARY... Isolated severe thunderstorms are possible tonight through early morning Wednesday across parts of the Red River into Western Tennessee. ...Synopsis... A shortwave trough over the Northwest will amplify across the central states, with an embedded impulse moving into the Lower MO Valley to TX Panhandle by early morning Wednesday. Mid-level height falls and the southern periphery of west-southwesterlies above 40 kts at 500 mb will overspread the Red River to KY/TN. At the surface, a front in the Ark-La-Tex to TN Valley will gradually advance north. A minor surface cyclone should develop over the Lower MO Valley, with a trailing cold front accelerating late as a surface ridge builds down the High Plains. ...Mid-South... Convective potential will be focused tonight, when large-scale ascent increases ahead of the sharpening shortwave trough. Scattered to eventually widespread thunderstorms are expected overnight into early morning Wednesday. Deep-layer shear will initially be modest within a unidirectional west-southwesterly profile, but will increase late, especially along and east of the MS River. A pocket of modest buoyancy characterized by MLCAPE near 1000 J/kg should be centered near the Ark-La-Tex. Progressively weaker surface-based instability is expected with northeast extent, with uncertainty on how far that may extend beyond western TN. The western portion of sustained convection will offer potential for small to marginally severe hail and locally strong gusts. But these storms should tend to get undercut during the early morning, given the orientation of the deep-layer shear vector and the accelerating cold front. A broadening southwest/northeast-oriented convective line will probably evolve across parts of AR/TN. Hodograph curvature should be adequate for a threat of a brief tornado and isolated damaging gusts with the strongest embedded cells through the pre-dawn hours. ..Grams/Lyons.. 12/17/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1145 PM CST Mon Dec 16 2024 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE MID-SOUTH... ...SUMMARY... Isolated severe thunderstorms are possible tonight through early morning Wednesday across parts of the Red River into Western Tennessee. ...Synopsis... A shortwave trough over the Northwest will amplify across the central states, with an embedded impulse moving into the Lower MO Valley to TX Panhandle by early morning Wednesday. Mid-level height falls and the southern periphery of west-southwesterlies above 40 kts at 500 mb will overspread the Red River to KY/TN. At the surface, a front in the Ark-La-Tex to TN Valley will gradually advance north. A minor surface cyclone should develop over the Lower MO Valley, with a trailing cold front accelerating late as a surface ridge builds down the High Plains. ...Mid-South... Convective potential will be focused tonight, when large-scale ascent increases ahead of the sharpening shortwave trough. Scattered to eventually widespread thunderstorms are expected overnight into early morning Wednesday. Deep-layer shear will initially be modest within a unidirectional west-southwesterly profile, but will increase late, especially along and east of the MS River. A pocket of modest buoyancy characterized by MLCAPE near 1000 J/kg should be centered near the Ark-La-Tex. Progressively weaker surface-based instability is expected with northeast extent, with uncertainty on how far that may extend beyond western TN. The western portion of sustained convection will offer potential for small to marginally severe hail and locally strong gusts. But these storms should tend to get undercut during the early morning, given the orientation of the deep-layer shear vector and the accelerating cold front. A broadening southwest/northeast-oriented convective line will probably evolve across parts of AR/TN. Hodograph curvature should be adequate for a threat of a brief tornado and isolated damaging gusts with the strongest embedded cells through the pre-dawn hours. ..Grams/Lyons.. 12/17/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1145 PM CST Mon Dec 16 2024 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE MID-SOUTH... ...SUMMARY... Isolated severe thunderstorms are possible tonight through early morning Wednesday across parts of the Red River into Western Tennessee. ...Synopsis... A shortwave trough over the Northwest will amplify across the central states, with an embedded impulse moving into the Lower MO Valley to TX Panhandle by early morning Wednesday. Mid-level height falls and the southern periphery of west-southwesterlies above 40 kts at 500 mb will overspread the Red River to KY/TN. At the surface, a front in the Ark-La-Tex to TN Valley will gradually advance north. A minor surface cyclone should develop over the Lower MO Valley, with a trailing cold front accelerating late as a surface ridge builds down the High Plains. ...Mid-South... Convective potential will be focused tonight, when large-scale ascent increases ahead of the sharpening shortwave trough. Scattered to eventually widespread thunderstorms are expected overnight into early morning Wednesday. Deep-layer shear will initially be modest within a unidirectional west-southwesterly profile, but will increase late, especially along and east of the MS River. A pocket of modest buoyancy characterized by MLCAPE near 1000 J/kg should be centered near the Ark-La-Tex. Progressively weaker surface-based instability is expected with northeast extent, with uncertainty on how far that may extend beyond western TN. The western portion of sustained convection will offer potential for small to marginally severe hail and locally strong gusts. But these storms should tend to get undercut during the early morning, given the orientation of the deep-layer shear vector and the accelerating cold front. A broadening southwest/northeast-oriented convective line will probably evolve across parts of AR/TN. Hodograph curvature should be adequate for a threat of a brief tornado and isolated damaging gusts with the strongest embedded cells through the pre-dawn hours. ..Grams/Lyons.. 12/17/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1145 PM CST Mon Dec 16 2024 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE MID-SOUTH... ...SUMMARY... Isolated severe thunderstorms are possible tonight through early morning Wednesday across parts of the Red River into Western Tennessee. ...Synopsis... A shortwave trough over the Northwest will amplify across the central states, with an embedded impulse moving into the Lower MO Valley to TX Panhandle by early morning Wednesday. Mid-level height falls and the southern periphery of west-southwesterlies above 40 kts at 500 mb will overspread the Red River to KY/TN. At the surface, a front in the Ark-La-Tex to TN Valley will gradually advance north. A minor surface cyclone should develop over the Lower MO Valley, with a trailing cold front accelerating late as a surface ridge builds down the High Plains. ...Mid-South... Convective potential will be focused tonight, when large-scale ascent increases ahead of the sharpening shortwave trough. Scattered to eventually widespread thunderstorms are expected overnight into early morning Wednesday. Deep-layer shear will initially be modest within a unidirectional west-southwesterly profile, but will increase late, especially along and east of the MS River. A pocket of modest buoyancy characterized by MLCAPE near 1000 J/kg should be centered near the Ark-La-Tex. Progressively weaker surface-based instability is expected with northeast extent, with uncertainty on how far that may extend beyond western TN. The western portion of sustained convection will offer potential for small to marginally severe hail and locally strong gusts. But these storms should tend to get undercut during the early morning, given the orientation of the deep-layer shear vector and the accelerating cold front. A broadening southwest/northeast-oriented convective line will probably evolve across parts of AR/TN. Hodograph curvature should be adequate for a threat of a brief tornado and isolated damaging gusts with the strongest embedded cells through the pre-dawn hours. ..Grams/Lyons.. 12/17/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1145 PM CST Mon Dec 16 2024 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE MID-SOUTH... ...SUMMARY... Isolated severe thunderstorms are possible tonight through early morning Wednesday across parts of the Red River into Western Tennessee. ...Synopsis... A shortwave trough over the Northwest will amplify across the central states, with an embedded impulse moving into the Lower MO Valley to TX Panhandle by early morning Wednesday. Mid-level height falls and the southern periphery of west-southwesterlies above 40 kts at 500 mb will overspread the Red River to KY/TN. At the surface, a front in the Ark-La-Tex to TN Valley will gradually advance north. A minor surface cyclone should develop over the Lower MO Valley, with a trailing cold front accelerating late as a surface ridge builds down the High Plains. ...Mid-South... Convective potential will be focused tonight, when large-scale ascent increases ahead of the sharpening shortwave trough. Scattered to eventually widespread thunderstorms are expected overnight into early morning Wednesday. Deep-layer shear will initially be modest within a unidirectional west-southwesterly profile, but will increase late, especially along and east of the MS River. A pocket of modest buoyancy characterized by MLCAPE near 1000 J/kg should be centered near the Ark-La-Tex. Progressively weaker surface-based instability is expected with northeast extent, with uncertainty on how far that may extend beyond western TN. The western portion of sustained convection will offer potential for small to marginally severe hail and locally strong gusts. But these storms should tend to get undercut during the early morning, given the orientation of the deep-layer shear vector and the accelerating cold front. A broadening southwest/northeast-oriented convective line will probably evolve across parts of AR/TN. Hodograph curvature should be adequate for a threat of a brief tornado and isolated damaging gusts with the strongest embedded cells through the pre-dawn hours. ..Grams/Lyons.. 12/17/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0649 PM CST Mon Dec 16 2024 Valid 170100Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN NORTHEAST TX TO SOUTHERN AR... ...SUMMARY... Small to marginally severe hail will remain possible into late evening across a portion of northeast Texas into southern Arkansas. ...Northeast TX to southern AR... A swath of scattered convection is ongoing from the Mid-South to the southeast side of the Metroplex, along a slow-moving cold front. 00Z SHV sounding sampled MLCAPE near 800 J/kg with moderately steep mid-level lapse rates around 7 C/km and modest effective bulk shear of 25-30 kts. MRMS MESH signatures of 0.5-1.0 hail have been noted over the past few hours within weakly rotating updrafts. This trend may persist for another couple hours before the effects of gradual boundary-layer cooling mitigate stronger storms. With negligible large-scale ascent, beyond convergence along the front, convective activity appears unlikely to greatly strengthen tonight. ..Grams.. 12/17/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0649 PM CST Mon Dec 16 2024 Valid 170100Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN NORTHEAST TX TO SOUTHERN AR... ...SUMMARY... Small to marginally severe hail will remain possible into late evening across a portion of northeast Texas into southern Arkansas. ...Northeast TX to southern AR... A swath of scattered convection is ongoing from the Mid-South to the southeast side of the Metroplex, along a slow-moving cold front. 00Z SHV sounding sampled MLCAPE near 800 J/kg with moderately steep mid-level lapse rates around 7 C/km and modest effective bulk shear of 25-30 kts. MRMS MESH signatures of 0.5-1.0 hail have been noted over the past few hours within weakly rotating updrafts. This trend may persist for another couple hours before the effects of gradual boundary-layer cooling mitigate stronger storms. With negligible large-scale ascent, beyond convergence along the front, convective activity appears unlikely to greatly strengthen tonight. ..Grams.. 12/17/2024 Read more

No Mesoscale Discussions are in effect as of Mon Dec 16 22:20:01 UTC 2024.

No watches are valid as of Mon Dec 16 22:20:01 UTC 2024.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0337 PM CST Mon Dec 16 2024 Valid 181200Z - 241200Z The upper-level pattern will be characterized by amplified ridging in the West with broad troughing in the East. Shortwave troughs are expected to progress through parts of the central and eastern U.S. through the rest of this week. Model guidance suggests the western ridge will break down this weekend into early next week. With the more progressive pattern east of the Divide, surface high pressure and colder air is expected to filter into the these areas. Fire weather concerns for most areas will be minimal. Some areas of stronger downslope winds are possible in the central High Plains vicinity as the shortwave troughs move through. Given the colder temperatures, it is not clear how much fire weather concern will develop, but fuels in that region remain dry enough to support increased risk at least on a localized basis. Moderately strong high pressure in the Great Basin will drive offshore winds across parts of southern California. Upper-level wind support will be notably lacking for this event. How low RH will be, especially on Wednesday morning, is also uncertain. With winds through the typical Santa Ana corridors peaking Wednesday morning, the current thinking is that there will be a few hours of critical fire weather as RH begins decrease with daytime heating. Winds are expected to diminish during the afternoon/evening. ..Wendt.. 12/16/2024 ...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 0337 PM CST Mon Dec 16 2024 Valid 181200Z - 241200Z The upper-level pattern will be characterized by amplified ridging in the West with broad troughing in the East. Shortwave troughs are expected to progress through parts of the central and eastern U.S. through the rest of this week. Model guidance suggests the western ridge will break down this weekend into early next week. With the more progressive pattern east of the Divide, surface high pressure and colder air is expected to filter into the these areas. Fire weather concerns for most areas will be minimal. Some areas of stronger downslope winds are possible in the central High Plains vicinity as the shortwave troughs move through. Given the colder temperatures, it is not clear how much fire weather concern will develop, but fuels in that region remain dry enough to support increased risk at least on a localized basis. Moderately strong high pressure in the Great Basin will drive offshore winds across parts of southern California. Upper-level wind support will be notably lacking for this event. How low RH will be, especially on Wednesday morning, is also uncertain. With winds through the typical Santa Ana corridors peaking Wednesday morning, the current thinking is that there will be a few hours of critical fire weather as RH begins decrease with daytime heating. Winds are expected to diminish during the afternoon/evening. ..Wendt.. 12/16/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more