Aggregator

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1219 AM CST Sun Dec 15 2024 Valid 161200Z - 171200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorm potential is expected to be low on Monday. ...TX/OK/MO to the Lower MS Valley... An upper trough over the northern/central Plains and Upper Midwest Monday morning will weaken as it shifts east/northeast across the Great Lakes. The strongest deep-layer southwesterly flow associated with this system will mainly be focused over the Mid/Lower MO and Mid-MS Valleys into the Great Lakes. Though, modest vertical shear will extend as far south as eastern OK and the Ozarks into the ArkLaTex vicinity. At the surface, a cold front is forecast to extend from southeast MO into southeast OK and northwest Texas Monday morning. This front will track east/southeast through the period, becoming positioned from the TN Valley toward the ArkLaTex and central TX by Tuesday morning. Ahead of the front, upper 50s to mid 60s dewpoints will be maintained by south/southwesterly low-level flow from central TX toward the MO Bootheel and the Lower MS Valley. Scattered elevated thunderstorms are likely to be ongoing from eastern OK into southern MO and parts of AR. Additional convection will develop near the southeast-advancing cold front as far northeast as the Lower OH Valley and southeast into central TX and the ArkLaTex/Lower MS Valley through the period. Stronger large-scale ascent and vertical shear will remain focused north, and out of phase with, the area of better low-level moisture across the south-central states. A couple of stronger storms may produce small hail early in the period from eastern OK toward the MO Bootheel. However, low-level inhibition and poor low-level lapse rates are expected to limit surface-based instability. Deep-layer flow parallel to the surface boundary, limited surface-based instability, and weakening shear/ascent with southward extent, should limit overall severe potential on Monday. ..Leitman.. 12/15/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1144 PM CST Sat Dec 14 2024 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN FAR NORTH TX TO NORTHWEST AR... ...SUMMARY... A low-end severe threat, primarily in the form of marginal hail, is possible tonight across a portion of the Red River Valley into the southern Ozark Plateau. ...Synopsis... A shortwave trough will progress from the northern Great Basin into the Upper Midwest by tonight, with low-amplitude impulses moving east across the Southwest. Primary surface cyclone will deepen as it tracks from the Black Hills to the Lake of the Woods vicinity. An occluded/cold front will arc south into the Ozarks by tonight, with trailing portion extending southwestward in OK/TX. ...North TX to the Lower OH Valley... A broad, low-level warm/moist conveyor will become established from the Lower Rio Grande Valley northeastward into the Lower OH Valley through tonight. Low-amplitude shortwave ridging should preclude appreciable thunderstorm development until late evening. A swath of elevated storms is expected to blossom into the overnight, from parts of eastern OK into the Lower OH Valley as weak mid-level height falls overspread the gradually moistening corridor. The southwest extent of this regime into far north TX should contain surface-based parcels, although low-level lapse rates may be poor. Nearly unidirectional southwesterly wind profiles are progged across much of the warm conveyor, ahead of the similarly oriented cold front. M-shaped type hodographs are anticipated from southeast OK southwestward, with weakness in the flow around 700 mb, where MUCAPE appears largest from 1000-2000 J/kg. Non-FV3 members of the 00Z HREF and available NSSL-MPAS runs indicate minimal 2-5 km UH signal. Given these factors, storm mode will probably become messy early in the convective development life cycle. Still, conditional potential exists, amid an adequate combo of effective bulk shear and MUCAPE, for a few deeper updrafts to acquire transient rotation, with an associated marginally severe hail threat. Where exactly that transitions to purely small hail magnitudes is uncertain with northeast extent, as mid-level lapse rates should be more muted and buoyancy will be less. ..Grams/Lyons.. 12/15/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1144 PM CST Sat Dec 14 2024 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN FAR NORTH TX TO NORTHWEST AR... ...SUMMARY... A low-end severe threat, primarily in the form of marginal hail, is possible tonight across a portion of the Red River Valley into the southern Ozark Plateau. ...Synopsis... A shortwave trough will progress from the northern Great Basin into the Upper Midwest by tonight, with low-amplitude impulses moving east across the Southwest. Primary surface cyclone will deepen as it tracks from the Black Hills to the Lake of the Woods vicinity. An occluded/cold front will arc south into the Ozarks by tonight, with trailing portion extending southwestward in OK/TX. ...North TX to the Lower OH Valley... A broad, low-level warm/moist conveyor will become established from the Lower Rio Grande Valley northeastward into the Lower OH Valley through tonight. Low-amplitude shortwave ridging should preclude appreciable thunderstorm development until late evening. A swath of elevated storms is expected to blossom into the overnight, from parts of eastern OK into the Lower OH Valley as weak mid-level height falls overspread the gradually moistening corridor. The southwest extent of this regime into far north TX should contain surface-based parcels, although low-level lapse rates may be poor. Nearly unidirectional southwesterly wind profiles are progged across much of the warm conveyor, ahead of the similarly oriented cold front. M-shaped type hodographs are anticipated from southeast OK southwestward, with weakness in the flow around 700 mb, where MUCAPE appears largest from 1000-2000 J/kg. Non-FV3 members of the 00Z HREF and available NSSL-MPAS runs indicate minimal 2-5 km UH signal. Given these factors, storm mode will probably become messy early in the convective development life cycle. Still, conditional potential exists, amid an adequate combo of effective bulk shear and MUCAPE, for a few deeper updrafts to acquire transient rotation, with an associated marginally severe hail threat. Where exactly that transitions to purely small hail magnitudes is uncertain with northeast extent, as mid-level lapse rates should be more muted and buoyancy will be less. ..Grams/Lyons.. 12/15/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1144 PM CST Sat Dec 14 2024 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN FAR NORTH TX TO NORTHWEST AR... ...SUMMARY... A low-end severe threat, primarily in the form of marginal hail, is possible tonight across a portion of the Red River Valley into the southern Ozark Plateau. ...Synopsis... A shortwave trough will progress from the northern Great Basin into the Upper Midwest by tonight, with low-amplitude impulses moving east across the Southwest. Primary surface cyclone will deepen as it tracks from the Black Hills to the Lake of the Woods vicinity. An occluded/cold front will arc south into the Ozarks by tonight, with trailing portion extending southwestward in OK/TX. ...North TX to the Lower OH Valley... A broad, low-level warm/moist conveyor will become established from the Lower Rio Grande Valley northeastward into the Lower OH Valley through tonight. Low-amplitude shortwave ridging should preclude appreciable thunderstorm development until late evening. A swath of elevated storms is expected to blossom into the overnight, from parts of eastern OK into the Lower OH Valley as weak mid-level height falls overspread the gradually moistening corridor. The southwest extent of this regime into far north TX should contain surface-based parcels, although low-level lapse rates may be poor. Nearly unidirectional southwesterly wind profiles are progged across much of the warm conveyor, ahead of the similarly oriented cold front. M-shaped type hodographs are anticipated from southeast OK southwestward, with weakness in the flow around 700 mb, where MUCAPE appears largest from 1000-2000 J/kg. Non-FV3 members of the 00Z HREF and available NSSL-MPAS runs indicate minimal 2-5 km UH signal. Given these factors, storm mode will probably become messy early in the convective development life cycle. Still, conditional potential exists, amid an adequate combo of effective bulk shear and MUCAPE, for a few deeper updrafts to acquire transient rotation, with an associated marginally severe hail threat. Where exactly that transitions to purely small hail magnitudes is uncertain with northeast extent, as mid-level lapse rates should be more muted and buoyancy will be less. ..Grams/Lyons.. 12/15/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1144 PM CST Sat Dec 14 2024 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN FAR NORTH TX TO NORTHWEST AR... ...SUMMARY... A low-end severe threat, primarily in the form of marginal hail, is possible tonight across a portion of the Red River Valley into the southern Ozark Plateau. ...Synopsis... A shortwave trough will progress from the northern Great Basin into the Upper Midwest by tonight, with low-amplitude impulses moving east across the Southwest. Primary surface cyclone will deepen as it tracks from the Black Hills to the Lake of the Woods vicinity. An occluded/cold front will arc south into the Ozarks by tonight, with trailing portion extending southwestward in OK/TX. ...North TX to the Lower OH Valley... A broad, low-level warm/moist conveyor will become established from the Lower Rio Grande Valley northeastward into the Lower OH Valley through tonight. Low-amplitude shortwave ridging should preclude appreciable thunderstorm development until late evening. A swath of elevated storms is expected to blossom into the overnight, from parts of eastern OK into the Lower OH Valley as weak mid-level height falls overspread the gradually moistening corridor. The southwest extent of this regime into far north TX should contain surface-based parcels, although low-level lapse rates may be poor. Nearly unidirectional southwesterly wind profiles are progged across much of the warm conveyor, ahead of the similarly oriented cold front. M-shaped type hodographs are anticipated from southeast OK southwestward, with weakness in the flow around 700 mb, where MUCAPE appears largest from 1000-2000 J/kg. Non-FV3 members of the 00Z HREF and available NSSL-MPAS runs indicate minimal 2-5 km UH signal. Given these factors, storm mode will probably become messy early in the convective development life cycle. Still, conditional potential exists, amid an adequate combo of effective bulk shear and MUCAPE, for a few deeper updrafts to acquire transient rotation, with an associated marginally severe hail threat. Where exactly that transitions to purely small hail magnitudes is uncertain with northeast extent, as mid-level lapse rates should be more muted and buoyancy will be less. ..Grams/Lyons.. 12/15/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1144 PM CST Sat Dec 14 2024 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN FAR NORTH TX TO NORTHWEST AR... ...SUMMARY... A low-end severe threat, primarily in the form of marginal hail, is possible tonight across a portion of the Red River Valley into the southern Ozark Plateau. ...Synopsis... A shortwave trough will progress from the northern Great Basin into the Upper Midwest by tonight, with low-amplitude impulses moving east across the Southwest. Primary surface cyclone will deepen as it tracks from the Black Hills to the Lake of the Woods vicinity. An occluded/cold front will arc south into the Ozarks by tonight, with trailing portion extending southwestward in OK/TX. ...North TX to the Lower OH Valley... A broad, low-level warm/moist conveyor will become established from the Lower Rio Grande Valley northeastward into the Lower OH Valley through tonight. Low-amplitude shortwave ridging should preclude appreciable thunderstorm development until late evening. A swath of elevated storms is expected to blossom into the overnight, from parts of eastern OK into the Lower OH Valley as weak mid-level height falls overspread the gradually moistening corridor. The southwest extent of this regime into far north TX should contain surface-based parcels, although low-level lapse rates may be poor. Nearly unidirectional southwesterly wind profiles are progged across much of the warm conveyor, ahead of the similarly oriented cold front. M-shaped type hodographs are anticipated from southeast OK southwestward, with weakness in the flow around 700 mb, where MUCAPE appears largest from 1000-2000 J/kg. Non-FV3 members of the 00Z HREF and available NSSL-MPAS runs indicate minimal 2-5 km UH signal. Given these factors, storm mode will probably become messy early in the convective development life cycle. Still, conditional potential exists, amid an adequate combo of effective bulk shear and MUCAPE, for a few deeper updrafts to acquire transient rotation, with an associated marginally severe hail threat. Where exactly that transitions to purely small hail magnitudes is uncertain with northeast extent, as mid-level lapse rates should be more muted and buoyancy will be less. ..Grams/Lyons.. 12/15/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0636 PM CST Sat Dec 14 2024 Valid 150100Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Discussion... Overall thunderstorm coverage will remain very isolated tonight. Convection near the cold core of a shortwave trough over central MO has nocturnally weakened. Still, scant elevated buoyancy might yield sporadic flashes as the trough continues east towards southern IN, and within the broad but modest low-level warm conveyor arcing back into the Ark-La-Miss. Greater buoyancy will remain confined to east TX but weak large-scale ascent suggests thunderstorm probabilities will be low. Sporadic thunderstorms may linger longest across parts of the Pacific Northwest coast. Here, steep mid-level lapse rates around 8 C/km per 00Z UIL/SLE soundings will eventually weaken as mid-level temperatures warm from south to north in the early morning. ..Grams.. 12/15/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0636 PM CST Sat Dec 14 2024 Valid 150100Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Discussion... Overall thunderstorm coverage will remain very isolated tonight. Convection near the cold core of a shortwave trough over central MO has nocturnally weakened. Still, scant elevated buoyancy might yield sporadic flashes as the trough continues east towards southern IN, and within the broad but modest low-level warm conveyor arcing back into the Ark-La-Miss. Greater buoyancy will remain confined to east TX but weak large-scale ascent suggests thunderstorm probabilities will be low. Sporadic thunderstorms may linger longest across parts of the Pacific Northwest coast. Here, steep mid-level lapse rates around 8 C/km per 00Z UIL/SLE soundings will eventually weaken as mid-level temperatures warm from south to north in the early morning. ..Grams.. 12/15/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0636 PM CST Sat Dec 14 2024 Valid 150100Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Discussion... Overall thunderstorm coverage will remain very isolated tonight. Convection near the cold core of a shortwave trough over central MO has nocturnally weakened. Still, scant elevated buoyancy might yield sporadic flashes as the trough continues east towards southern IN, and within the broad but modest low-level warm conveyor arcing back into the Ark-La-Miss. Greater buoyancy will remain confined to east TX but weak large-scale ascent suggests thunderstorm probabilities will be low. Sporadic thunderstorms may linger longest across parts of the Pacific Northwest coast. Here, steep mid-level lapse rates around 8 C/km per 00Z UIL/SLE soundings will eventually weaken as mid-level temperatures warm from south to north in the early morning. ..Grams.. 12/15/2024 Read more

No Mesoscale Discussions are in effect as of Sat Dec 14 22:22:02 UTC 2024.

No watches are valid as of Sat Dec 14 22:22:02 UTC 2024.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0320 PM CST Sat Dec 14 2024 Valid 161200Z - 221200Z A quasi-zonal, progressive upper-level pattern will be present this weekend into the middle of next week. Thereafter, some flow amplification is forecast to occur. Upper-level troughing will be the general pattern in the East with ridging over portions of the West. This pattern will favor cold air east of the Divide with seasonably warm temperatures farther west. Some colder air/high pressure will filter into the Great Basin and drive offshore winds in parts of southern California. With the passage of successive upper-level shortwave troughs, some dry and breezy conditions are possible in parts of the High Plains. Where precipitation remains minimal, locally heightened fire concerns could develop next week. Given the cooler temperatures expected, critical fire weather probability will remain low. Offshore flow in southern California will likely be the main area of concern for fire weather. The offshore pressure gradient still appears it will be maximized Tuesday night into Wednesday morning. Deterministic and ensemble guidance has not changed significantly in terms of the upper-level and surface pattern over the past several model cycles. Upper-level wind support should be minimal. The main variation in guidance is with the magnitude of the offshore pressure gradient. 40% critical probabilities will remain for Tuesday/Wednesday and trends in the offshore gradient will continue to be monitored. ..Wendt.. 12/14/2024 ...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 0320 PM CST Sat Dec 14 2024 Valid 161200Z - 221200Z A quasi-zonal, progressive upper-level pattern will be present this weekend into the middle of next week. Thereafter, some flow amplification is forecast to occur. Upper-level troughing will be the general pattern in the East with ridging over portions of the West. This pattern will favor cold air east of the Divide with seasonably warm temperatures farther west. Some colder air/high pressure will filter into the Great Basin and drive offshore winds in parts of southern California. With the passage of successive upper-level shortwave troughs, some dry and breezy conditions are possible in parts of the High Plains. Where precipitation remains minimal, locally heightened fire concerns could develop next week. Given the cooler temperatures expected, critical fire weather probability will remain low. Offshore flow in southern California will likely be the main area of concern for fire weather. The offshore pressure gradient still appears it will be maximized Tuesday night into Wednesday morning. Deterministic and ensemble guidance has not changed significantly in terms of the upper-level and surface pattern over the past several model cycles. Upper-level wind support should be minimal. The main variation in guidance is with the magnitude of the offshore pressure gradient. 40% critical probabilities will remain for Tuesday/Wednesday and trends in the offshore gradient will continue to be monitored. ..Wendt.. 12/14/2024 ...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 0320 PM CST Sat Dec 14 2024 Valid 161200Z - 221200Z A quasi-zonal, progressive upper-level pattern will be present this weekend into the middle of next week. Thereafter, some flow amplification is forecast to occur. Upper-level troughing will be the general pattern in the East with ridging over portions of the West. This pattern will favor cold air east of the Divide with seasonably warm temperatures farther west. Some colder air/high pressure will filter into the Great Basin and drive offshore winds in parts of southern California. With the passage of successive upper-level shortwave troughs, some dry and breezy conditions are possible in parts of the High Plains. Where precipitation remains minimal, locally heightened fire concerns could develop next week. Given the cooler temperatures expected, critical fire weather probability will remain low. Offshore flow in southern California will likely be the main area of concern for fire weather. The offshore pressure gradient still appears it will be maximized Tuesday night into Wednesday morning. Deterministic and ensemble guidance has not changed significantly in terms of the upper-level and surface pattern over the past several model cycles. Upper-level wind support should be minimal. The main variation in guidance is with the magnitude of the offshore pressure gradient. 40% critical probabilities will remain for Tuesday/Wednesday and trends in the offshore gradient will continue to be monitored. ..Wendt.. 12/14/2024 ...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 0320 PM CST Sat Dec 14 2024 Valid 161200Z - 221200Z A quasi-zonal, progressive upper-level pattern will be present this weekend into the middle of next week. Thereafter, some flow amplification is forecast to occur. Upper-level troughing will be the general pattern in the East with ridging over portions of the West. This pattern will favor cold air east of the Divide with seasonably warm temperatures farther west. Some colder air/high pressure will filter into the Great Basin and drive offshore winds in parts of southern California. With the passage of successive upper-level shortwave troughs, some dry and breezy conditions are possible in parts of the High Plains. Where precipitation remains minimal, locally heightened fire concerns could develop next week. Given the cooler temperatures expected, critical fire weather probability will remain low. Offshore flow in southern California will likely be the main area of concern for fire weather. The offshore pressure gradient still appears it will be maximized Tuesday night into Wednesday morning. Deterministic and ensemble guidance has not changed significantly in terms of the upper-level and surface pattern over the past several model cycles. Upper-level wind support should be minimal. The main variation in guidance is with the magnitude of the offshore pressure gradient. 40% critical probabilities will remain for Tuesday/Wednesday and trends in the offshore gradient will continue to be monitored. ..Wendt.. 12/14/2024 ...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 0320 PM CST Sat Dec 14 2024 Valid 161200Z - 221200Z A quasi-zonal, progressive upper-level pattern will be present this weekend into the middle of next week. Thereafter, some flow amplification is forecast to occur. Upper-level troughing will be the general pattern in the East with ridging over portions of the West. This pattern will favor cold air east of the Divide with seasonably warm temperatures farther west. Some colder air/high pressure will filter into the Great Basin and drive offshore winds in parts of southern California. With the passage of successive upper-level shortwave troughs, some dry and breezy conditions are possible in parts of the High Plains. Where precipitation remains minimal, locally heightened fire concerns could develop next week. Given the cooler temperatures expected, critical fire weather probability will remain low. Offshore flow in southern California will likely be the main area of concern for fire weather. The offshore pressure gradient still appears it will be maximized Tuesday night into Wednesday morning. Deterministic and ensemble guidance has not changed significantly in terms of the upper-level and surface pattern over the past several model cycles. Upper-level wind support should be minimal. The main variation in guidance is with the magnitude of the offshore pressure gradient. 40% critical probabilities will remain for Tuesday/Wednesday and trends in the offshore gradient will continue to be monitored. ..Wendt.. 12/14/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0153 PM CST Sat Dec 14 2024 Valid 142000Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms are not expected through tonight. ...20Z Update... The western edge of thunderstorm probabilities have been trimmed in the middle MS Valley vicinity, where additional thunderstorm development appears unlikely behind the strongly forced band of convection shifting eastward -- in tandem with the midlevel shortwave trough. Farther west, thunderstorm probabilities were also removed over portions of the Coastal Range in northern CA. Forecast soundings suggest EL temperatures/instability are no longer supportive of lightning here. For additional details, see the previous discussion below. ..Weinman.. 12/14/2024 .PREV DISCUSSION... /ISSUED 1030 AM CST Sat Dec 14 2024/ ...Coastal California... The Marginal Risk across parts of coastal CA has been removed with this update. The 12Z OAK sounding showed a dearth of boundary-layer instability, and a line of low-topped convection has weakened as it moves inland in tandem with a shortwave trough also tracking quickly eastward. While strong winds will remain possible in the short term given the enhanced low/mid-level flow noted on recent VWPs from KMUX, the lack of appreciable surface-based instability is expected to limit the overall severe threat for the rest of the period. ...East/Southeast Texas... A shortwave trough over the southern/central Plains this morning will continue to eject eastward across the mid MS Valley through tonight. Related surface low over eastern KS is forecast to weaken in this time frame, as high pressure will remain entrenched over the East Coast. A cold front is expected to stall over parts of east to central TX later today. While a favorably moist low-level airmass will be in place ahead of this front, limited large-scale ascent and poor lapse rates aloft should hinder robust updrafts and organized severe potential across east/southeast TX. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0153 PM CST Sat Dec 14 2024 Valid 142000Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms are not expected through tonight. ...20Z Update... The western edge of thunderstorm probabilities have been trimmed in the middle MS Valley vicinity, where additional thunderstorm development appears unlikely behind the strongly forced band of convection shifting eastward -- in tandem with the midlevel shortwave trough. Farther west, thunderstorm probabilities were also removed over portions of the Coastal Range in northern CA. Forecast soundings suggest EL temperatures/instability are no longer supportive of lightning here. For additional details, see the previous discussion below. ..Weinman.. 12/14/2024 .PREV DISCUSSION... /ISSUED 1030 AM CST Sat Dec 14 2024/ ...Coastal California... The Marginal Risk across parts of coastal CA has been removed with this update. The 12Z OAK sounding showed a dearth of boundary-layer instability, and a line of low-topped convection has weakened as it moves inland in tandem with a shortwave trough also tracking quickly eastward. While strong winds will remain possible in the short term given the enhanced low/mid-level flow noted on recent VWPs from KMUX, the lack of appreciable surface-based instability is expected to limit the overall severe threat for the rest of the period. ...East/Southeast Texas... A shortwave trough over the southern/central Plains this morning will continue to eject eastward across the mid MS Valley through tonight. Related surface low over eastern KS is forecast to weaken in this time frame, as high pressure will remain entrenched over the East Coast. A cold front is expected to stall over parts of east to central TX later today. While a favorably moist low-level airmass will be in place ahead of this front, limited large-scale ascent and poor lapse rates aloft should hinder robust updrafts and organized severe potential across east/southeast TX. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0153 PM CST Sat Dec 14 2024 Valid 142000Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms are not expected through tonight. ...20Z Update... The western edge of thunderstorm probabilities have been trimmed in the middle MS Valley vicinity, where additional thunderstorm development appears unlikely behind the strongly forced band of convection shifting eastward -- in tandem with the midlevel shortwave trough. Farther west, thunderstorm probabilities were also removed over portions of the Coastal Range in northern CA. Forecast soundings suggest EL temperatures/instability are no longer supportive of lightning here. For additional details, see the previous discussion below. ..Weinman.. 12/14/2024 .PREV DISCUSSION... /ISSUED 1030 AM CST Sat Dec 14 2024/ ...Coastal California... The Marginal Risk across parts of coastal CA has been removed with this update. The 12Z OAK sounding showed a dearth of boundary-layer instability, and a line of low-topped convection has weakened as it moves inland in tandem with a shortwave trough also tracking quickly eastward. While strong winds will remain possible in the short term given the enhanced low/mid-level flow noted on recent VWPs from KMUX, the lack of appreciable surface-based instability is expected to limit the overall severe threat for the rest of the period. ...East/Southeast Texas... A shortwave trough over the southern/central Plains this morning will continue to eject eastward across the mid MS Valley through tonight. Related surface low over eastern KS is forecast to weaken in this time frame, as high pressure will remain entrenched over the East Coast. A cold front is expected to stall over parts of east to central TX later today. While a favorably moist low-level airmass will be in place ahead of this front, limited large-scale ascent and poor lapse rates aloft should hinder robust updrafts and organized severe potential across east/southeast TX. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0153 PM CST Sat Dec 14 2024 Valid 142000Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms are not expected through tonight. ...20Z Update... The western edge of thunderstorm probabilities have been trimmed in the middle MS Valley vicinity, where additional thunderstorm development appears unlikely behind the strongly forced band of convection shifting eastward -- in tandem with the midlevel shortwave trough. Farther west, thunderstorm probabilities were also removed over portions of the Coastal Range in northern CA. Forecast soundings suggest EL temperatures/instability are no longer supportive of lightning here. For additional details, see the previous discussion below. ..Weinman.. 12/14/2024 .PREV DISCUSSION... /ISSUED 1030 AM CST Sat Dec 14 2024/ ...Coastal California... The Marginal Risk across parts of coastal CA has been removed with this update. The 12Z OAK sounding showed a dearth of boundary-layer instability, and a line of low-topped convection has weakened as it moves inland in tandem with a shortwave trough also tracking quickly eastward. While strong winds will remain possible in the short term given the enhanced low/mid-level flow noted on recent VWPs from KMUX, the lack of appreciable surface-based instability is expected to limit the overall severe threat for the rest of the period. ...East/Southeast Texas... A shortwave trough over the southern/central Plains this morning will continue to eject eastward across the mid MS Valley through tonight. Related surface low over eastern KS is forecast to weaken in this time frame, as high pressure will remain entrenched over the East Coast. A cold front is expected to stall over parts of east to central TX later today. While a favorably moist low-level airmass will be in place ahead of this front, limited large-scale ascent and poor lapse rates aloft should hinder robust updrafts and organized severe potential across east/southeast TX. Read more