Severe Storms

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1213 AM CDT Tue Sep 24 2024 Valid 251200Z - 261200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm potential is low on Wednesday. ...Synopsis... An upper low within the base of the larger-scale upper trough extending from the Great Lakes to the Lower MS Valley will become cut-off from northern stream flow on Wednesday. As this occurs, the northern shortwave trough will progress east across the Great Lakes and southern Ontario. The developing upper cyclone over the Mid-South/Lower MS Valley will not move much through the period. However, moderately enhanced southerly deep-layer flow on the eastern flank of the cut-off low will persist over the Southeast. Meanwhile, latest forecast guidance and NHC forecasts show a strengthening tropical cyclone emerging across the eastern Gulf of Mexico. This system is forecast to remain well offshore from the southwest FL coast through 12z Thursday. ...Southeast... A stalled surface boundary/inverted trough will extend from near coastal MS/AL northeast across the central Appalachians. Near and east of this boundary, south/southeasterly low-level flow will maintain a very moist airmass with dewpoints from the mid 60s to low 70s F. Potentially widespread convection may be ongoing Wednesday morning across portions of this area, limiting destabilization. Despite vertical shear that may otherwise support organized convection, weak instability and poor lapse rates will limit severe potential, though the strongest cells may produce locally gusty winds. Further south across the FL Peninsula, southeasterly low to midlevel flow will increase, especially after 00z, as the developing tropical cyclone emerges into the eastern Gulf. Forecast soundings show enlarged, favorably curved low-level hodographs developing late in the period. However, instability across the Peninsula is expected to remain weak through early Thursday morning. At this time, tropical cyclone related tornado potential appears limited through 12z Thursday. ...Upper OH Valley/Lower Great Lakes vicinity... A cold front will move east/southeast across the Lower Great Lakes during the afternoon and into the overnight hours. Ahead of this feature, a corridor of 60s F dewpoints will be in place. However, surface heating is expected to be muted by cloud cover and showers. As a result, instability will be weak and lapse rates will remain poor, precluding severe thunderstorm potential. ..Leitman.. 09/24/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1213 AM CDT Tue Sep 24 2024 Valid 251200Z - 261200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm potential is low on Wednesday. ...Synopsis... An upper low within the base of the larger-scale upper trough extending from the Great Lakes to the Lower MS Valley will become cut-off from northern stream flow on Wednesday. As this occurs, the northern shortwave trough will progress east across the Great Lakes and southern Ontario. The developing upper cyclone over the Mid-South/Lower MS Valley will not move much through the period. However, moderately enhanced southerly deep-layer flow on the eastern flank of the cut-off low will persist over the Southeast. Meanwhile, latest forecast guidance and NHC forecasts show a strengthening tropical cyclone emerging across the eastern Gulf of Mexico. This system is forecast to remain well offshore from the southwest FL coast through 12z Thursday. ...Southeast... A stalled surface boundary/inverted trough will extend from near coastal MS/AL northeast across the central Appalachians. Near and east of this boundary, south/southeasterly low-level flow will maintain a very moist airmass with dewpoints from the mid 60s to low 70s F. Potentially widespread convection may be ongoing Wednesday morning across portions of this area, limiting destabilization. Despite vertical shear that may otherwise support organized convection, weak instability and poor lapse rates will limit severe potential, though the strongest cells may produce locally gusty winds. Further south across the FL Peninsula, southeasterly low to midlevel flow will increase, especially after 00z, as the developing tropical cyclone emerges into the eastern Gulf. Forecast soundings show enlarged, favorably curved low-level hodographs developing late in the period. However, instability across the Peninsula is expected to remain weak through early Thursday morning. At this time, tropical cyclone related tornado potential appears limited through 12z Thursday. ...Upper OH Valley/Lower Great Lakes vicinity... A cold front will move east/southeast across the Lower Great Lakes during the afternoon and into the overnight hours. Ahead of this feature, a corridor of 60s F dewpoints will be in place. However, surface heating is expected to be muted by cloud cover and showers. As a result, instability will be weak and lapse rates will remain poor, precluding severe thunderstorm potential. ..Leitman.. 09/24/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1213 AM CDT Tue Sep 24 2024 Valid 251200Z - 261200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm potential is low on Wednesday. ...Synopsis... An upper low within the base of the larger-scale upper trough extending from the Great Lakes to the Lower MS Valley will become cut-off from northern stream flow on Wednesday. As this occurs, the northern shortwave trough will progress east across the Great Lakes and southern Ontario. The developing upper cyclone over the Mid-South/Lower MS Valley will not move much through the period. However, moderately enhanced southerly deep-layer flow on the eastern flank of the cut-off low will persist over the Southeast. Meanwhile, latest forecast guidance and NHC forecasts show a strengthening tropical cyclone emerging across the eastern Gulf of Mexico. This system is forecast to remain well offshore from the southwest FL coast through 12z Thursday. ...Southeast... A stalled surface boundary/inverted trough will extend from near coastal MS/AL northeast across the central Appalachians. Near and east of this boundary, south/southeasterly low-level flow will maintain a very moist airmass with dewpoints from the mid 60s to low 70s F. Potentially widespread convection may be ongoing Wednesday morning across portions of this area, limiting destabilization. Despite vertical shear that may otherwise support organized convection, weak instability and poor lapse rates will limit severe potential, though the strongest cells may produce locally gusty winds. Further south across the FL Peninsula, southeasterly low to midlevel flow will increase, especially after 00z, as the developing tropical cyclone emerges into the eastern Gulf. Forecast soundings show enlarged, favorably curved low-level hodographs developing late in the period. However, instability across the Peninsula is expected to remain weak through early Thursday morning. At this time, tropical cyclone related tornado potential appears limited through 12z Thursday. ...Upper OH Valley/Lower Great Lakes vicinity... A cold front will move east/southeast across the Lower Great Lakes during the afternoon and into the overnight hours. Ahead of this feature, a corridor of 60s F dewpoints will be in place. However, surface heating is expected to be muted by cloud cover and showers. As a result, instability will be weak and lapse rates will remain poor, precluding severe thunderstorm potential. ..Leitman.. 09/24/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1213 AM CDT Tue Sep 24 2024 Valid 251200Z - 261200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm potential is low on Wednesday. ...Synopsis... An upper low within the base of the larger-scale upper trough extending from the Great Lakes to the Lower MS Valley will become cut-off from northern stream flow on Wednesday. As this occurs, the northern shortwave trough will progress east across the Great Lakes and southern Ontario. The developing upper cyclone over the Mid-South/Lower MS Valley will not move much through the period. However, moderately enhanced southerly deep-layer flow on the eastern flank of the cut-off low will persist over the Southeast. Meanwhile, latest forecast guidance and NHC forecasts show a strengthening tropical cyclone emerging across the eastern Gulf of Mexico. This system is forecast to remain well offshore from the southwest FL coast through 12z Thursday. ...Southeast... A stalled surface boundary/inverted trough will extend from near coastal MS/AL northeast across the central Appalachians. Near and east of this boundary, south/southeasterly low-level flow will maintain a very moist airmass with dewpoints from the mid 60s to low 70s F. Potentially widespread convection may be ongoing Wednesday morning across portions of this area, limiting destabilization. Despite vertical shear that may otherwise support organized convection, weak instability and poor lapse rates will limit severe potential, though the strongest cells may produce locally gusty winds. Further south across the FL Peninsula, southeasterly low to midlevel flow will increase, especially after 00z, as the developing tropical cyclone emerges into the eastern Gulf. Forecast soundings show enlarged, favorably curved low-level hodographs developing late in the period. However, instability across the Peninsula is expected to remain weak through early Thursday morning. At this time, tropical cyclone related tornado potential appears limited through 12z Thursday. ...Upper OH Valley/Lower Great Lakes vicinity... A cold front will move east/southeast across the Lower Great Lakes during the afternoon and into the overnight hours. Ahead of this feature, a corridor of 60s F dewpoints will be in place. However, surface heating is expected to be muted by cloud cover and showers. As a result, instability will be weak and lapse rates will remain poor, precluding severe thunderstorm potential. ..Leitman.. 09/24/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1213 AM CDT Tue Sep 24 2024 Valid 251200Z - 261200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm potential is low on Wednesday. ...Synopsis... An upper low within the base of the larger-scale upper trough extending from the Great Lakes to the Lower MS Valley will become cut-off from northern stream flow on Wednesday. As this occurs, the northern shortwave trough will progress east across the Great Lakes and southern Ontario. The developing upper cyclone over the Mid-South/Lower MS Valley will not move much through the period. However, moderately enhanced southerly deep-layer flow on the eastern flank of the cut-off low will persist over the Southeast. Meanwhile, latest forecast guidance and NHC forecasts show a strengthening tropical cyclone emerging across the eastern Gulf of Mexico. This system is forecast to remain well offshore from the southwest FL coast through 12z Thursday. ...Southeast... A stalled surface boundary/inverted trough will extend from near coastal MS/AL northeast across the central Appalachians. Near and east of this boundary, south/southeasterly low-level flow will maintain a very moist airmass with dewpoints from the mid 60s to low 70s F. Potentially widespread convection may be ongoing Wednesday morning across portions of this area, limiting destabilization. Despite vertical shear that may otherwise support organized convection, weak instability and poor lapse rates will limit severe potential, though the strongest cells may produce locally gusty winds. Further south across the FL Peninsula, southeasterly low to midlevel flow will increase, especially after 00z, as the developing tropical cyclone emerges into the eastern Gulf. Forecast soundings show enlarged, favorably curved low-level hodographs developing late in the period. However, instability across the Peninsula is expected to remain weak through early Thursday morning. At this time, tropical cyclone related tornado potential appears limited through 12z Thursday. ...Upper OH Valley/Lower Great Lakes vicinity... A cold front will move east/southeast across the Lower Great Lakes during the afternoon and into the overnight hours. Ahead of this feature, a corridor of 60s F dewpoints will be in place. However, surface heating is expected to be muted by cloud cover and showers. As a result, instability will be weak and lapse rates will remain poor, precluding severe thunderstorm potential. ..Leitman.. 09/24/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1213 AM CDT Tue Sep 24 2024 Valid 251200Z - 261200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm potential is low on Wednesday. ...Synopsis... An upper low within the base of the larger-scale upper trough extending from the Great Lakes to the Lower MS Valley will become cut-off from northern stream flow on Wednesday. As this occurs, the northern shortwave trough will progress east across the Great Lakes and southern Ontario. The developing upper cyclone over the Mid-South/Lower MS Valley will not move much through the period. However, moderately enhanced southerly deep-layer flow on the eastern flank of the cut-off low will persist over the Southeast. Meanwhile, latest forecast guidance and NHC forecasts show a strengthening tropical cyclone emerging across the eastern Gulf of Mexico. This system is forecast to remain well offshore from the southwest FL coast through 12z Thursday. ...Southeast... A stalled surface boundary/inverted trough will extend from near coastal MS/AL northeast across the central Appalachians. Near and east of this boundary, south/southeasterly low-level flow will maintain a very moist airmass with dewpoints from the mid 60s to low 70s F. Potentially widespread convection may be ongoing Wednesday morning across portions of this area, limiting destabilization. Despite vertical shear that may otherwise support organized convection, weak instability and poor lapse rates will limit severe potential, though the strongest cells may produce locally gusty winds. Further south across the FL Peninsula, southeasterly low to midlevel flow will increase, especially after 00z, as the developing tropical cyclone emerges into the eastern Gulf. Forecast soundings show enlarged, favorably curved low-level hodographs developing late in the period. However, instability across the Peninsula is expected to remain weak through early Thursday morning. At this time, tropical cyclone related tornado potential appears limited through 12z Thursday. ...Upper OH Valley/Lower Great Lakes vicinity... A cold front will move east/southeast across the Lower Great Lakes during the afternoon and into the overnight hours. Ahead of this feature, a corridor of 60s F dewpoints will be in place. However, surface heating is expected to be muted by cloud cover and showers. As a result, instability will be weak and lapse rates will remain poor, precluding severe thunderstorm potential. ..Leitman.. 09/24/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1213 AM CDT Tue Sep 24 2024 Valid 251200Z - 261200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm potential is low on Wednesday. ...Synopsis... An upper low within the base of the larger-scale upper trough extending from the Great Lakes to the Lower MS Valley will become cut-off from northern stream flow on Wednesday. As this occurs, the northern shortwave trough will progress east across the Great Lakes and southern Ontario. The developing upper cyclone over the Mid-South/Lower MS Valley will not move much through the period. However, moderately enhanced southerly deep-layer flow on the eastern flank of the cut-off low will persist over the Southeast. Meanwhile, latest forecast guidance and NHC forecasts show a strengthening tropical cyclone emerging across the eastern Gulf of Mexico. This system is forecast to remain well offshore from the southwest FL coast through 12z Thursday. ...Southeast... A stalled surface boundary/inverted trough will extend from near coastal MS/AL northeast across the central Appalachians. Near and east of this boundary, south/southeasterly low-level flow will maintain a very moist airmass with dewpoints from the mid 60s to low 70s F. Potentially widespread convection may be ongoing Wednesday morning across portions of this area, limiting destabilization. Despite vertical shear that may otherwise support organized convection, weak instability and poor lapse rates will limit severe potential, though the strongest cells may produce locally gusty winds. Further south across the FL Peninsula, southeasterly low to midlevel flow will increase, especially after 00z, as the developing tropical cyclone emerges into the eastern Gulf. Forecast soundings show enlarged, favorably curved low-level hodographs developing late in the period. However, instability across the Peninsula is expected to remain weak through early Thursday morning. At this time, tropical cyclone related tornado potential appears limited through 12z Thursday. ...Upper OH Valley/Lower Great Lakes vicinity... A cold front will move east/southeast across the Lower Great Lakes during the afternoon and into the overnight hours. Ahead of this feature, a corridor of 60s F dewpoints will be in place. However, surface heating is expected to be muted by cloud cover and showers. As a result, instability will be weak and lapse rates will remain poor, precluding severe thunderstorm potential. ..Leitman.. 09/24/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1232 AM CDT Tue Sep 24 2024 Valid 241200Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE TENNESSEE AND OHIO VALLEYS INTO THE SOUTHERN APPALACHIANS. A FEW STRONG/SEVERE STORMS ARE ALSO POSSIBLE OVER THE SOUTHERN PLAINS.... ...SUMMARY... Isolated to scattered severe thunderstorms are possible today across portions of the Ohio and Tennessee Valleys into the central/southern Appalachians. A few strong/severe storms are also possible across portions of the southern Plains. ...Ohio and Tennessee Valleys to southern Appalachians... Positive-tilt short-wave trough is ejecting east across the mid MS Valley early this morning. This feature is gradually deamplifying as it's kicked downstream in advance of an upstream short-wave trough that's digging across the Plains. As a result, 500mb flow should increase across the TN/OH Valley region, and high-level flow will become increasingly diffluent. Early this morning, an elongated corridor of convection continues ahead of this feature, extending from southwest IN into southeast MO. Some form of this activity will likely be ongoing at the start of the period, immediately ahead of the front. While the early-day convection should not be particularly robust, boundary-layer heating should aid destabilization, especially south of the OH River where 0-3km lapse rates should steepen by 18z allowing MLCAPE values to increase to 1000-2000 J/kg. While deep-layer flow will be decidedly southwesterly, effective shear will be more than adequate for sustaining longer-lived clusters and even a few supercells. Forecast soundings suggest convection should develop fairly early in the period as mid-level lapse rates are poor, but convective temperatures will be breached quickly with temperatures rising through the 70s to near 80F. Primary concern with these storms will be damaging winds. ...Southern Plains... Upper ridge is forecast to build east into the Rockies during the day1 period, but this will allow a strong upper trough to dig south-southeast across the Plains as a 500mb speed max translates down the back side into western KS by 25/00z. Left exit region of this feature will encourage large-scale ascent, and a weak surface wave/low should evolve over southwest KS/northwest OK by early afternoon. This evolution will result in strong boundary-layer heating across the TX South Plains into northwest OK. Forecast soundings suggest 0-3km lapse rates will approach dry adiabatic by 21z, and convective temperatures will be breached in the upper 80s to near 90F. While LLJ is not expected to be particularly noteworthy, profiles across northwest into central OK will favor supercells as low-level flow will be decidedly southeasterly through 1km, and effective shear will be strong (50kt). Additionally, MLCAPE values in excess of 1000 J/kg should support robust updrafts. Will introduce low severe probabilities for hail/wind for supercells that evolve during the mid-late afternoon. This activity will spread south-southeast during the evening hours in advance of the digging short wave. Will continue to monitor this region, but at this time coverage of severe may not warrant higher probabilities. ..Darrow/Thornton.. 09/24/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1232 AM CDT Tue Sep 24 2024 Valid 241200Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE TENNESSEE AND OHIO VALLEYS INTO THE SOUTHERN APPALACHIANS. A FEW STRONG/SEVERE STORMS ARE ALSO POSSIBLE OVER THE SOUTHERN PLAINS.... ...SUMMARY... Isolated to scattered severe thunderstorms are possible today across portions of the Ohio and Tennessee Valleys into the central/southern Appalachians. A few strong/severe storms are also possible across portions of the southern Plains. ...Ohio and Tennessee Valleys to southern Appalachians... Positive-tilt short-wave trough is ejecting east across the mid MS Valley early this morning. This feature is gradually deamplifying as it's kicked downstream in advance of an upstream short-wave trough that's digging across the Plains. As a result, 500mb flow should increase across the TN/OH Valley region, and high-level flow will become increasingly diffluent. Early this morning, an elongated corridor of convection continues ahead of this feature, extending from southwest IN into southeast MO. Some form of this activity will likely be ongoing at the start of the period, immediately ahead of the front. While the early-day convection should not be particularly robust, boundary-layer heating should aid destabilization, especially south of the OH River where 0-3km lapse rates should steepen by 18z allowing MLCAPE values to increase to 1000-2000 J/kg. While deep-layer flow will be decidedly southwesterly, effective shear will be more than adequate for sustaining longer-lived clusters and even a few supercells. Forecast soundings suggest convection should develop fairly early in the period as mid-level lapse rates are poor, but convective temperatures will be breached quickly with temperatures rising through the 70s to near 80F. Primary concern with these storms will be damaging winds. ...Southern Plains... Upper ridge is forecast to build east into the Rockies during the day1 period, but this will allow a strong upper trough to dig south-southeast across the Plains as a 500mb speed max translates down the back side into western KS by 25/00z. Left exit region of this feature will encourage large-scale ascent, and a weak surface wave/low should evolve over southwest KS/northwest OK by early afternoon. This evolution will result in strong boundary-layer heating across the TX South Plains into northwest OK. Forecast soundings suggest 0-3km lapse rates will approach dry adiabatic by 21z, and convective temperatures will be breached in the upper 80s to near 90F. While LLJ is not expected to be particularly noteworthy, profiles across northwest into central OK will favor supercells as low-level flow will be decidedly southeasterly through 1km, and effective shear will be strong (50kt). Additionally, MLCAPE values in excess of 1000 J/kg should support robust updrafts. Will introduce low severe probabilities for hail/wind for supercells that evolve during the mid-late afternoon. This activity will spread south-southeast during the evening hours in advance of the digging short wave. Will continue to monitor this region, but at this time coverage of severe may not warrant higher probabilities. ..Darrow/Thornton.. 09/24/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1232 AM CDT Tue Sep 24 2024 Valid 241200Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE TENNESSEE AND OHIO VALLEYS INTO THE SOUTHERN APPALACHIANS. A FEW STRONG/SEVERE STORMS ARE ALSO POSSIBLE OVER THE SOUTHERN PLAINS.... ...SUMMARY... Isolated to scattered severe thunderstorms are possible today across portions of the Ohio and Tennessee Valleys into the central/southern Appalachians. A few strong/severe storms are also possible across portions of the southern Plains. ...Ohio and Tennessee Valleys to southern Appalachians... Positive-tilt short-wave trough is ejecting east across the mid MS Valley early this morning. This feature is gradually deamplifying as it's kicked downstream in advance of an upstream short-wave trough that's digging across the Plains. As a result, 500mb flow should increase across the TN/OH Valley region, and high-level flow will become increasingly diffluent. Early this morning, an elongated corridor of convection continues ahead of this feature, extending from southwest IN into southeast MO. Some form of this activity will likely be ongoing at the start of the period, immediately ahead of the front. While the early-day convection should not be particularly robust, boundary-layer heating should aid destabilization, especially south of the OH River where 0-3km lapse rates should steepen by 18z allowing MLCAPE values to increase to 1000-2000 J/kg. While deep-layer flow will be decidedly southwesterly, effective shear will be more than adequate for sustaining longer-lived clusters and even a few supercells. Forecast soundings suggest convection should develop fairly early in the period as mid-level lapse rates are poor, but convective temperatures will be breached quickly with temperatures rising through the 70s to near 80F. Primary concern with these storms will be damaging winds. ...Southern Plains... Upper ridge is forecast to build east into the Rockies during the day1 period, but this will allow a strong upper trough to dig south-southeast across the Plains as a 500mb speed max translates down the back side into western KS by 25/00z. Left exit region of this feature will encourage large-scale ascent, and a weak surface wave/low should evolve over southwest KS/northwest OK by early afternoon. This evolution will result in strong boundary-layer heating across the TX South Plains into northwest OK. Forecast soundings suggest 0-3km lapse rates will approach dry adiabatic by 21z, and convective temperatures will be breached in the upper 80s to near 90F. While LLJ is not expected to be particularly noteworthy, profiles across northwest into central OK will favor supercells as low-level flow will be decidedly southeasterly through 1km, and effective shear will be strong (50kt). Additionally, MLCAPE values in excess of 1000 J/kg should support robust updrafts. Will introduce low severe probabilities for hail/wind for supercells that evolve during the mid-late afternoon. This activity will spread south-southeast during the evening hours in advance of the digging short wave. Will continue to monitor this region, but at this time coverage of severe may not warrant higher probabilities. ..Darrow/Thornton.. 09/24/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1232 AM CDT Tue Sep 24 2024 Valid 241200Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE TENNESSEE AND OHIO VALLEYS INTO THE SOUTHERN APPALACHIANS. A FEW STRONG/SEVERE STORMS ARE ALSO POSSIBLE OVER THE SOUTHERN PLAINS.... ...SUMMARY... Isolated to scattered severe thunderstorms are possible today across portions of the Ohio and Tennessee Valleys into the central/southern Appalachians. A few strong/severe storms are also possible across portions of the southern Plains. ...Ohio and Tennessee Valleys to southern Appalachians... Positive-tilt short-wave trough is ejecting east across the mid MS Valley early this morning. This feature is gradually deamplifying as it's kicked downstream in advance of an upstream short-wave trough that's digging across the Plains. As a result, 500mb flow should increase across the TN/OH Valley region, and high-level flow will become increasingly diffluent. Early this morning, an elongated corridor of convection continues ahead of this feature, extending from southwest IN into southeast MO. Some form of this activity will likely be ongoing at the start of the period, immediately ahead of the front. While the early-day convection should not be particularly robust, boundary-layer heating should aid destabilization, especially south of the OH River where 0-3km lapse rates should steepen by 18z allowing MLCAPE values to increase to 1000-2000 J/kg. While deep-layer flow will be decidedly southwesterly, effective shear will be more than adequate for sustaining longer-lived clusters and even a few supercells. Forecast soundings suggest convection should develop fairly early in the period as mid-level lapse rates are poor, but convective temperatures will be breached quickly with temperatures rising through the 70s to near 80F. Primary concern with these storms will be damaging winds. ...Southern Plains... Upper ridge is forecast to build east into the Rockies during the day1 period, but this will allow a strong upper trough to dig south-southeast across the Plains as a 500mb speed max translates down the back side into western KS by 25/00z. Left exit region of this feature will encourage large-scale ascent, and a weak surface wave/low should evolve over southwest KS/northwest OK by early afternoon. This evolution will result in strong boundary-layer heating across the TX South Plains into northwest OK. Forecast soundings suggest 0-3km lapse rates will approach dry adiabatic by 21z, and convective temperatures will be breached in the upper 80s to near 90F. While LLJ is not expected to be particularly noteworthy, profiles across northwest into central OK will favor supercells as low-level flow will be decidedly southeasterly through 1km, and effective shear will be strong (50kt). Additionally, MLCAPE values in excess of 1000 J/kg should support robust updrafts. Will introduce low severe probabilities for hail/wind for supercells that evolve during the mid-late afternoon. This activity will spread south-southeast during the evening hours in advance of the digging short wave. Will continue to monitor this region, but at this time coverage of severe may not warrant higher probabilities. ..Darrow/Thornton.. 09/24/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1232 AM CDT Tue Sep 24 2024 Valid 241200Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE TENNESSEE AND OHIO VALLEYS INTO THE SOUTHERN APPALACHIANS. A FEW STRONG/SEVERE STORMS ARE ALSO POSSIBLE OVER THE SOUTHERN PLAINS.... ...SUMMARY... Isolated to scattered severe thunderstorms are possible today across portions of the Ohio and Tennessee Valleys into the central/southern Appalachians. A few strong/severe storms are also possible across portions of the southern Plains. ...Ohio and Tennessee Valleys to southern Appalachians... Positive-tilt short-wave trough is ejecting east across the mid MS Valley early this morning. This feature is gradually deamplifying as it's kicked downstream in advance of an upstream short-wave trough that's digging across the Plains. As a result, 500mb flow should increase across the TN/OH Valley region, and high-level flow will become increasingly diffluent. Early this morning, an elongated corridor of convection continues ahead of this feature, extending from southwest IN into southeast MO. Some form of this activity will likely be ongoing at the start of the period, immediately ahead of the front. While the early-day convection should not be particularly robust, boundary-layer heating should aid destabilization, especially south of the OH River where 0-3km lapse rates should steepen by 18z allowing MLCAPE values to increase to 1000-2000 J/kg. While deep-layer flow will be decidedly southwesterly, effective shear will be more than adequate for sustaining longer-lived clusters and even a few supercells. Forecast soundings suggest convection should develop fairly early in the period as mid-level lapse rates are poor, but convective temperatures will be breached quickly with temperatures rising through the 70s to near 80F. Primary concern with these storms will be damaging winds. ...Southern Plains... Upper ridge is forecast to build east into the Rockies during the day1 period, but this will allow a strong upper trough to dig south-southeast across the Plains as a 500mb speed max translates down the back side into western KS by 25/00z. Left exit region of this feature will encourage large-scale ascent, and a weak surface wave/low should evolve over southwest KS/northwest OK by early afternoon. This evolution will result in strong boundary-layer heating across the TX South Plains into northwest OK. Forecast soundings suggest 0-3km lapse rates will approach dry adiabatic by 21z, and convective temperatures will be breached in the upper 80s to near 90F. While LLJ is not expected to be particularly noteworthy, profiles across northwest into central OK will favor supercells as low-level flow will be decidedly southeasterly through 1km, and effective shear will be strong (50kt). Additionally, MLCAPE values in excess of 1000 J/kg should support robust updrafts. Will introduce low severe probabilities for hail/wind for supercells that evolve during the mid-late afternoon. This activity will spread south-southeast during the evening hours in advance of the digging short wave. Will continue to monitor this region, but at this time coverage of severe may not warrant higher probabilities. ..Darrow/Thornton.. 09/24/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1232 AM CDT Tue Sep 24 2024 Valid 241200Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE TENNESSEE AND OHIO VALLEYS INTO THE SOUTHERN APPALACHIANS. A FEW STRONG/SEVERE STORMS ARE ALSO POSSIBLE OVER THE SOUTHERN PLAINS.... ...SUMMARY... Isolated to scattered severe thunderstorms are possible today across portions of the Ohio and Tennessee Valleys into the central/southern Appalachians. A few strong/severe storms are also possible across portions of the southern Plains. ...Ohio and Tennessee Valleys to southern Appalachians... Positive-tilt short-wave trough is ejecting east across the mid MS Valley early this morning. This feature is gradually deamplifying as it's kicked downstream in advance of an upstream short-wave trough that's digging across the Plains. As a result, 500mb flow should increase across the TN/OH Valley region, and high-level flow will become increasingly diffluent. Early this morning, an elongated corridor of convection continues ahead of this feature, extending from southwest IN into southeast MO. Some form of this activity will likely be ongoing at the start of the period, immediately ahead of the front. While the early-day convection should not be particularly robust, boundary-layer heating should aid destabilization, especially south of the OH River where 0-3km lapse rates should steepen by 18z allowing MLCAPE values to increase to 1000-2000 J/kg. While deep-layer flow will be decidedly southwesterly, effective shear will be more than adequate for sustaining longer-lived clusters and even a few supercells. Forecast soundings suggest convection should develop fairly early in the period as mid-level lapse rates are poor, but convective temperatures will be breached quickly with temperatures rising through the 70s to near 80F. Primary concern with these storms will be damaging winds. ...Southern Plains... Upper ridge is forecast to build east into the Rockies during the day1 period, but this will allow a strong upper trough to dig south-southeast across the Plains as a 500mb speed max translates down the back side into western KS by 25/00z. Left exit region of this feature will encourage large-scale ascent, and a weak surface wave/low should evolve over southwest KS/northwest OK by early afternoon. This evolution will result in strong boundary-layer heating across the TX South Plains into northwest OK. Forecast soundings suggest 0-3km lapse rates will approach dry adiabatic by 21z, and convective temperatures will be breached in the upper 80s to near 90F. While LLJ is not expected to be particularly noteworthy, profiles across northwest into central OK will favor supercells as low-level flow will be decidedly southeasterly through 1km, and effective shear will be strong (50kt). Additionally, MLCAPE values in excess of 1000 J/kg should support robust updrafts. Will introduce low severe probabilities for hail/wind for supercells that evolve during the mid-late afternoon. This activity will spread south-southeast during the evening hours in advance of the digging short wave. Will continue to monitor this region, but at this time coverage of severe may not warrant higher probabilities. ..Darrow/Thornton.. 09/24/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1232 AM CDT Tue Sep 24 2024 Valid 241200Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE TENNESSEE AND OHIO VALLEYS INTO THE SOUTHERN APPALACHIANS. A FEW STRONG/SEVERE STORMS ARE ALSO POSSIBLE OVER THE SOUTHERN PLAINS.... ...SUMMARY... Isolated to scattered severe thunderstorms are possible today across portions of the Ohio and Tennessee Valleys into the central/southern Appalachians. A few strong/severe storms are also possible across portions of the southern Plains. ...Ohio and Tennessee Valleys to southern Appalachians... Positive-tilt short-wave trough is ejecting east across the mid MS Valley early this morning. This feature is gradually deamplifying as it's kicked downstream in advance of an upstream short-wave trough that's digging across the Plains. As a result, 500mb flow should increase across the TN/OH Valley region, and high-level flow will become increasingly diffluent. Early this morning, an elongated corridor of convection continues ahead of this feature, extending from southwest IN into southeast MO. Some form of this activity will likely be ongoing at the start of the period, immediately ahead of the front. While the early-day convection should not be particularly robust, boundary-layer heating should aid destabilization, especially south of the OH River where 0-3km lapse rates should steepen by 18z allowing MLCAPE values to increase to 1000-2000 J/kg. While deep-layer flow will be decidedly southwesterly, effective shear will be more than adequate for sustaining longer-lived clusters and even a few supercells. Forecast soundings suggest convection should develop fairly early in the period as mid-level lapse rates are poor, but convective temperatures will be breached quickly with temperatures rising through the 70s to near 80F. Primary concern with these storms will be damaging winds. ...Southern Plains... Upper ridge is forecast to build east into the Rockies during the day1 period, but this will allow a strong upper trough to dig south-southeast across the Plains as a 500mb speed max translates down the back side into western KS by 25/00z. Left exit region of this feature will encourage large-scale ascent, and a weak surface wave/low should evolve over southwest KS/northwest OK by early afternoon. This evolution will result in strong boundary-layer heating across the TX South Plains into northwest OK. Forecast soundings suggest 0-3km lapse rates will approach dry adiabatic by 21z, and convective temperatures will be breached in the upper 80s to near 90F. While LLJ is not expected to be particularly noteworthy, profiles across northwest into central OK will favor supercells as low-level flow will be decidedly southeasterly through 1km, and effective shear will be strong (50kt). Additionally, MLCAPE values in excess of 1000 J/kg should support robust updrafts. Will introduce low severe probabilities for hail/wind for supercells that evolve during the mid-late afternoon. This activity will spread south-southeast during the evening hours in advance of the digging short wave. Will continue to monitor this region, but at this time coverage of severe may not warrant higher probabilities. ..Darrow/Thornton.. 09/24/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0738 PM CDT Mon Sep 23 2024 Valid 240100Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS TO PARTS OF THE TENNESSEE AND OHIO VALLEYS... ...SUMMARY... Isolated strong to locally severe thunderstorms remain possible this evening from the Ozarks into parts of the Tennessee and lower Ohio Valleys. ...01z Update... Positive-tilt short-wave trough has advanced into IA-eastern KS-OK early this evening as upstream height falls appear to now be influencing the movement of this feature. Large-scale ascent is spreading across the mid Mississippi Valley into the lower Ohio Valley, and one reflection of this stronger forcing is expressed as a corridor of convection that extends from south of Springfield IL-STL-extreme northern AR. Low-level warm advection continues ahead of this activity with 10-15kt, 1km southwesterly flow from near the confluence of the MS/OH Rivers into central KY. While effective shear is not particularly strong, it's adequate for at least organized clusters and perhaps a weak supercell or two. Given the weak lapse rates, locally damaging winds should be the greatest concern this evening. ..Darrow.. 09/24/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0738 PM CDT Mon Sep 23 2024 Valid 240100Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS TO PARTS OF THE TENNESSEE AND OHIO VALLEYS... ...SUMMARY... Isolated strong to locally severe thunderstorms remain possible this evening from the Ozarks into parts of the Tennessee and lower Ohio Valleys. ...01z Update... Positive-tilt short-wave trough has advanced into IA-eastern KS-OK early this evening as upstream height falls appear to now be influencing the movement of this feature. Large-scale ascent is spreading across the mid Mississippi Valley into the lower Ohio Valley, and one reflection of this stronger forcing is expressed as a corridor of convection that extends from south of Springfield IL-STL-extreme northern AR. Low-level warm advection continues ahead of this activity with 10-15kt, 1km southwesterly flow from near the confluence of the MS/OH Rivers into central KY. While effective shear is not particularly strong, it's adequate for at least organized clusters and perhaps a weak supercell or two. Given the weak lapse rates, locally damaging winds should be the greatest concern this evening. ..Darrow.. 09/24/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0738 PM CDT Mon Sep 23 2024 Valid 240100Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE OZARKS TO PARTS OF THE TENNESSEE AND OHIO VALLEYS... ...SUMMARY... Isolated strong to locally severe thunderstorms remain possible this evening from the Ozarks into parts of the Tennessee and lower Ohio Valleys. ...01z Update... Positive-tilt short-wave trough has advanced into IA-eastern KS-OK early this evening as upstream height falls appear to now be influencing the movement of this feature. Large-scale ascent is spreading across the mid Mississippi Valley into the lower Ohio Valley, and one reflection of this stronger forcing is expressed as a corridor of convection that extends from south of Springfield IL-STL-extreme northern AR. Low-level warm advection continues ahead of this activity with 10-15kt, 1km southwesterly flow from near the confluence of the MS/OH Rivers into central KY. While effective shear is not particularly strong, it's adequate for at least organized clusters and perhaps a weak supercell or two. Given the weak lapse rates, locally damaging winds should be the greatest concern this evening. ..Darrow.. 09/24/2024 Read more

No watches are valid as of Mon Sep 23 23:20:07 UTC 2024.

No Mesoscale Discussions are in effect as of Mon Sep 23 23:20:07 UTC 2024.

MD 2098 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHEASTERN MISSOURI AND NORTHEASTERN ARKANSAS INTO THE MID MISSISSIPPI/LOWER OHIO/TENNESSEE VALLEYS
Mesoscale Discussion 2098 NWS Storm Prediction Center Norman OK 0332 PM CDT Mon Sep 23 2024 Areas affected...southeastern Missouri and northeastern Arkansas into the Mid Mississippi/Lower Ohio/Tennessee Valleys Concerning...Severe potential...Watch unlikely Valid 232032Z - 232300Z Probability of Watch Issuance...20 percent SUMMARY...Gradually increasing convection will pose some risk for gusty winds and hail, possibly reaching severe levels locally. A tornado also cannot be ruled out, though overall limited/marginal nature of the risk expected at this time may preclude the need for WW consideration. DISCUSSION...Latest visible satellite imagery shows some thinning of the high clouds across southeastern Missouri and into Arkansas, near and ahead of the surface cold front. Resulting, filtered heating has allowed 1000 to 1500 J/kg mixed-layer CAPE to evolve near and ahead of the boundary. This is supporting a gradual increase in convective coverage across the Mid Mississippi/Lower Ohio/Tennessee Valleys -- and westward into the Ozarks just to the cool side of the front. This increase includes a small/weakly rotating storm moving eastward across New Madrid County Missouri at this time. Low-level flow remains generally veered across the warm sector, limiting shear in the lowest 1km AGL. Still, 30 to 40 kt west-southwesterlies at mid levels will continue to provide shear sufficient to support organized updrafts. Ascent crossing Missouri/Arkansas at this time -- associated with a mid-level vort max -- suggests some further increase in convective coverage/intensity over the next couple of hours. While we will continue to monitor evolution, present indications remain that WW issuance should remain unnecessary. ..Goss/Guyer.. 09/23/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LMK...OHX...PAH...MEG...LSX...LZK...SGF... LAT...LON 36509225 37129079 37688976 37898795 37858688 36998690 35858800 34489103 34549181 35129232 36509225 Read more