Aggregator

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0200 PM CST Wed Dec 06 2023 Valid 071200Z - 081200Z ...NO CRITICAL AREAS... No changes. See previous discussion below. ..Bentley.. 12/06/2023 .PREV DISCUSSION... /ISSUED 1226 AM CST Wed Dec 06 2023/ ...Synopsis... A belt of strong mid-level westerly flow will move across the Rockies on Thursday. At the surface, a cyclone will begin to develop across the central Plains. As a result, dry and warm westerly downslope flow will increase across portions of the Southern Plains. Afternoon relative humidity reductions to around 15 percent will overlap sustained winds at 15-20 mph across portions of eastern New Mexico into the Texas and Oklahoma Panhandles. Fuels within this region are largely near normal moisture and only marginally receptive to spread. Locally Elevated fire weather conditions will be possible in areas where fine fuels have cured and become dormant. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0200 PM CST Wed Dec 06 2023 Valid 071200Z - 081200Z ...NO CRITICAL AREAS... No changes. See previous discussion below. ..Bentley.. 12/06/2023 .PREV DISCUSSION... /ISSUED 1226 AM CST Wed Dec 06 2023/ ...Synopsis... A belt of strong mid-level westerly flow will move across the Rockies on Thursday. At the surface, a cyclone will begin to develop across the central Plains. As a result, dry and warm westerly downslope flow will increase across portions of the Southern Plains. Afternoon relative humidity reductions to around 15 percent will overlap sustained winds at 15-20 mph across portions of eastern New Mexico into the Texas and Oklahoma Panhandles. Fuels within this region are largely near normal moisture and only marginally receptive to spread. Locally Elevated fire weather conditions will be possible in areas where fine fuels have cured and become dormant. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CST Wed Dec 06 2023 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Thursday. ...Synopsis... Embedded within a large-scale trough over the northwestern CONUS, a west-northwesterly midlevel jet streak will overspread northern CA early in the period, while a related weak surface low and cold front move ashore over the Pacific Northwest coast. Left-exit region ascent and frontal forcing will support multiple rounds of scattered eastward-spreading convection, focused over coastal WA/OR and northern CA. Despite poor boundary-layer moisture, cold temperatures aloft/steep lapse rates will still yield sufficient (albeit weak) instability for isolated/embedded low-topped thunderstorms. While modestly enhanced low-level shear is possible over northwestern CA/coastal OR early in the period, the weak buoyancy should limit strong/severe storm potential. As large-scale ascent accompanying the jet streak/midlevel impulse continues east-southeastward into the Intermountain West, steep lapse rates/weak instability could favor very isolated thunderstorms, though coverage of such activity appears too low for a General Thunderstorm area. ..Weinman/Leitman.. 12/06/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CST Wed Dec 06 2023 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Thursday. ...Synopsis... Embedded within a large-scale trough over the northwestern CONUS, a west-northwesterly midlevel jet streak will overspread northern CA early in the period, while a related weak surface low and cold front move ashore over the Pacific Northwest coast. Left-exit region ascent and frontal forcing will support multiple rounds of scattered eastward-spreading convection, focused over coastal WA/OR and northern CA. Despite poor boundary-layer moisture, cold temperatures aloft/steep lapse rates will still yield sufficient (albeit weak) instability for isolated/embedded low-topped thunderstorms. While modestly enhanced low-level shear is possible over northwestern CA/coastal OR early in the period, the weak buoyancy should limit strong/severe storm potential. As large-scale ascent accompanying the jet streak/midlevel impulse continues east-southeastward into the Intermountain West, steep lapse rates/weak instability could favor very isolated thunderstorms, though coverage of such activity appears too low for a General Thunderstorm area. ..Weinman/Leitman.. 12/06/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CST Wed Dec 06 2023 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Thursday. ...Synopsis... Embedded within a large-scale trough over the northwestern CONUS, a west-northwesterly midlevel jet streak will overspread northern CA early in the period, while a related weak surface low and cold front move ashore over the Pacific Northwest coast. Left-exit region ascent and frontal forcing will support multiple rounds of scattered eastward-spreading convection, focused over coastal WA/OR and northern CA. Despite poor boundary-layer moisture, cold temperatures aloft/steep lapse rates will still yield sufficient (albeit weak) instability for isolated/embedded low-topped thunderstorms. While modestly enhanced low-level shear is possible over northwestern CA/coastal OR early in the period, the weak buoyancy should limit strong/severe storm potential. As large-scale ascent accompanying the jet streak/midlevel impulse continues east-southeastward into the Intermountain West, steep lapse rates/weak instability could favor very isolated thunderstorms, though coverage of such activity appears too low for a General Thunderstorm area. ..Weinman/Leitman.. 12/06/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CST Wed Dec 06 2023 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Thursday. ...Synopsis... Embedded within a large-scale trough over the northwestern CONUS, a west-northwesterly midlevel jet streak will overspread northern CA early in the period, while a related weak surface low and cold front move ashore over the Pacific Northwest coast. Left-exit region ascent and frontal forcing will support multiple rounds of scattered eastward-spreading convection, focused over coastal WA/OR and northern CA. Despite poor boundary-layer moisture, cold temperatures aloft/steep lapse rates will still yield sufficient (albeit weak) instability for isolated/embedded low-topped thunderstorms. While modestly enhanced low-level shear is possible over northwestern CA/coastal OR early in the period, the weak buoyancy should limit strong/severe storm potential. As large-scale ascent accompanying the jet streak/midlevel impulse continues east-southeastward into the Intermountain West, steep lapse rates/weak instability could favor very isolated thunderstorms, though coverage of such activity appears too low for a General Thunderstorm area. ..Weinman/Leitman.. 12/06/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CST Wed Dec 06 2023 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Thursday. ...Synopsis... Embedded within a large-scale trough over the northwestern CONUS, a west-northwesterly midlevel jet streak will overspread northern CA early in the period, while a related weak surface low and cold front move ashore over the Pacific Northwest coast. Left-exit region ascent and frontal forcing will support multiple rounds of scattered eastward-spreading convection, focused over coastal WA/OR and northern CA. Despite poor boundary-layer moisture, cold temperatures aloft/steep lapse rates will still yield sufficient (albeit weak) instability for isolated/embedded low-topped thunderstorms. While modestly enhanced low-level shear is possible over northwestern CA/coastal OR early in the period, the weak buoyancy should limit strong/severe storm potential. As large-scale ascent accompanying the jet streak/midlevel impulse continues east-southeastward into the Intermountain West, steep lapse rates/weak instability could favor very isolated thunderstorms, though coverage of such activity appears too low for a General Thunderstorm area. ..Weinman/Leitman.. 12/06/2023 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1055 AM CST Wed Dec 06 2023 Valid 061700Z - 071200Z ...NO CRITICAL AREAS... No changes. See previous discussion below. ..Bentley.. 12/06/2023 .PREV DISCUSSION... /ISSUED 1224 AM CST Wed Dec 06 2023/ ...Synopsis... An upper-level high will continue to shift eastward across the central US as troughing develops across the west coast on Wednesday. Surface pressure gradients will increase between a surface high across the southeast and a surface low across the Rockies, with southwesterly breezes possible across portions of the High Plains. Pockets of locally elevated fire weather are possible in the southern High Plains and perhaps parts of southeast Wyoming should sufficiently dry fine fuels exist. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1055 AM CST Wed Dec 06 2023 Valid 061700Z - 071200Z ...NO CRITICAL AREAS... No changes. See previous discussion below. ..Bentley.. 12/06/2023 .PREV DISCUSSION... /ISSUED 1224 AM CST Wed Dec 06 2023/ ...Synopsis... An upper-level high will continue to shift eastward across the central US as troughing develops across the west coast on Wednesday. Surface pressure gradients will increase between a surface high across the southeast and a surface low across the Rockies, with southwesterly breezes possible across portions of the High Plains. Pockets of locally elevated fire weather are possible in the southern High Plains and perhaps parts of southeast Wyoming should sufficiently dry fine fuels exist. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1055 AM CST Wed Dec 06 2023 Valid 061700Z - 071200Z ...NO CRITICAL AREAS... No changes. See previous discussion below. ..Bentley.. 12/06/2023 .PREV DISCUSSION... /ISSUED 1224 AM CST Wed Dec 06 2023/ ...Synopsis... An upper-level high will continue to shift eastward across the central US as troughing develops across the west coast on Wednesday. Surface pressure gradients will increase between a surface high across the southeast and a surface low across the Rockies, with southwesterly breezes possible across portions of the High Plains. Pockets of locally elevated fire weather are possible in the southern High Plains and perhaps parts of southeast Wyoming should sufficiently dry fine fuels exist. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1055 AM CST Wed Dec 06 2023 Valid 061700Z - 071200Z ...NO CRITICAL AREAS... No changes. See previous discussion below. ..Bentley.. 12/06/2023 .PREV DISCUSSION... /ISSUED 1224 AM CST Wed Dec 06 2023/ ...Synopsis... An upper-level high will continue to shift eastward across the central US as troughing develops across the west coast on Wednesday. Surface pressure gradients will increase between a surface high across the southeast and a surface low across the Rockies, with southwesterly breezes possible across portions of the High Plains. Pockets of locally elevated fire weather are possible in the southern High Plains and perhaps parts of southeast Wyoming should sufficiently dry fine fuels exist. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1055 AM CST Wed Dec 06 2023 Valid 061700Z - 071200Z ...NO CRITICAL AREAS... No changes. See previous discussion below. ..Bentley.. 12/06/2023 .PREV DISCUSSION... /ISSUED 1224 AM CST Wed Dec 06 2023/ ...Synopsis... An upper-level high will continue to shift eastward across the central US as troughing develops across the west coast on Wednesday. Surface pressure gradients will increase between a surface high across the southeast and a surface low across the Rockies, with southwesterly breezes possible across portions of the High Plains. Pockets of locally elevated fire weather are possible in the southern High Plains and perhaps parts of southeast Wyoming should sufficiently dry fine fuels exist. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1055 AM CST Wed Dec 06 2023 Valid 061700Z - 071200Z ...NO CRITICAL AREAS... No changes. See previous discussion below. ..Bentley.. 12/06/2023 .PREV DISCUSSION... /ISSUED 1224 AM CST Wed Dec 06 2023/ ...Synopsis... An upper-level high will continue to shift eastward across the central US as troughing develops across the west coast on Wednesday. Surface pressure gradients will increase between a surface high across the southeast and a surface low across the Rockies, with southwesterly breezes possible across portions of the High Plains. Pockets of locally elevated fire weather are possible in the southern High Plains and perhaps parts of southeast Wyoming should sufficiently dry fine fuels exist. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1027 AM CST Wed Dec 06 2023 Valid 061630Z - 071200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are unlikely through tonight. ...Western OR and northern CA... A strong upper trough is approaching the coast of northern CA and southwest OR, with the associated surface cold front moving ashore in the next couple of hours. Strong onshore flow, lift in vicinity of the front, and cold temperatures aloft may result in isolated lightning flashes this afternoon along the coastal ranges and interior mountains of northern CA/western OR. Present indications are that this activity will be quite sparse. ...ID/MT... Later tonight, the aforementioned shortwave trough will track inland and affect portions of ID/MT. Steep mid-level lapse rates and continued strong large scale lift will result in convective showers over the mountains of central ID into western MT. Profiles will be quite cold, but pockets of weak instability may be sufficient for a few lightning flashes - mainly after midnight. ..Hart/Lyons.. 12/06/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1027 AM CST Wed Dec 06 2023 Valid 061630Z - 071200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are unlikely through tonight. ...Western OR and northern CA... A strong upper trough is approaching the coast of northern CA and southwest OR, with the associated surface cold front moving ashore in the next couple of hours. Strong onshore flow, lift in vicinity of the front, and cold temperatures aloft may result in isolated lightning flashes this afternoon along the coastal ranges and interior mountains of northern CA/western OR. Present indications are that this activity will be quite sparse. ...ID/MT... Later tonight, the aforementioned shortwave trough will track inland and affect portions of ID/MT. Steep mid-level lapse rates and continued strong large scale lift will result in convective showers over the mountains of central ID into western MT. Profiles will be quite cold, but pockets of weak instability may be sufficient for a few lightning flashes - mainly after midnight. ..Hart/Lyons.. 12/06/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1027 AM CST Wed Dec 06 2023 Valid 061630Z - 071200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are unlikely through tonight. ...Western OR and northern CA... A strong upper trough is approaching the coast of northern CA and southwest OR, with the associated surface cold front moving ashore in the next couple of hours. Strong onshore flow, lift in vicinity of the front, and cold temperatures aloft may result in isolated lightning flashes this afternoon along the coastal ranges and interior mountains of northern CA/western OR. Present indications are that this activity will be quite sparse. ...ID/MT... Later tonight, the aforementioned shortwave trough will track inland and affect portions of ID/MT. Steep mid-level lapse rates and continued strong large scale lift will result in convective showers over the mountains of central ID into western MT. Profiles will be quite cold, but pockets of weak instability may be sufficient for a few lightning flashes - mainly after midnight. ..Hart/Lyons.. 12/06/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1027 AM CST Wed Dec 06 2023 Valid 061630Z - 071200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are unlikely through tonight. ...Western OR and northern CA... A strong upper trough is approaching the coast of northern CA and southwest OR, with the associated surface cold front moving ashore in the next couple of hours. Strong onshore flow, lift in vicinity of the front, and cold temperatures aloft may result in isolated lightning flashes this afternoon along the coastal ranges and interior mountains of northern CA/western OR. Present indications are that this activity will be quite sparse. ...ID/MT... Later tonight, the aforementioned shortwave trough will track inland and affect portions of ID/MT. Steep mid-level lapse rates and continued strong large scale lift will result in convective showers over the mountains of central ID into western MT. Profiles will be quite cold, but pockets of weak instability may be sufficient for a few lightning flashes - mainly after midnight. ..Hart/Lyons.. 12/06/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1027 AM CST Wed Dec 06 2023 Valid 061630Z - 071200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are unlikely through tonight. ...Western OR and northern CA... A strong upper trough is approaching the coast of northern CA and southwest OR, with the associated surface cold front moving ashore in the next couple of hours. Strong onshore flow, lift in vicinity of the front, and cold temperatures aloft may result in isolated lightning flashes this afternoon along the coastal ranges and interior mountains of northern CA/western OR. Present indications are that this activity will be quite sparse. ...ID/MT... Later tonight, the aforementioned shortwave trough will track inland and affect portions of ID/MT. Steep mid-level lapse rates and continued strong large scale lift will result in convective showers over the mountains of central ID into western MT. Profiles will be quite cold, but pockets of weak instability may be sufficient for a few lightning flashes - mainly after midnight. ..Hart/Lyons.. 12/06/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0614 AM CST Wed Dec 06 2023 Valid 061300Z - 071200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are unlikely through tonight. ...Synopsis... In mid/upper levels, a progressive and highly amplified synoptic pattern will continue through the period. A substantial trough -- now just inland from and nearly parallel to the U.S. Atlantic Coast -- will move seaward before 00Z. Cold frontal passages related to this system will render the airmass over and east of the Intermountain West too stable and/or dry for thunderstorms. Meanwhile, upstream ridging will shift eastward from the Rockies across the Great Plains. This will occur as a Pacific synoptic trough -- along with a series of accompanying shortwaves and vorticity maxima -- shift inland across the Pacific Coast States from central CA northward. The leading -- and currently strongest -- of the shortwave troughs was apparent in moisture-channel imagery near 135W between about 33N-45N, preceded (as common for such troughs) by a baroclinic-leaf formation on satellite imagery. An associated band of frontogenetic forcing accompanied by a precip band should reach the coastline today. As that occurs -- and especially afterward in cooling air aloft (-20 to -30 deg C) and steepening low/middle-level lapse rates accompanying the strongest DCVA -- some of the convection may extend into icing layers suitable for lightning production. Isolated thunderstorm potential appears most probable over portions of northern CA and western OR, as well as overnight in the Bitterroots vicinity with columnar cooling/moistening. In each area, around 50-100 J/kg MUCAPE will support the convection. ..Edwards/Kerr.. 12/06/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0614 AM CST Wed Dec 06 2023 Valid 061300Z - 071200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are unlikely through tonight. ...Synopsis... In mid/upper levels, a progressive and highly amplified synoptic pattern will continue through the period. A substantial trough -- now just inland from and nearly parallel to the U.S. Atlantic Coast -- will move seaward before 00Z. Cold frontal passages related to this system will render the airmass over and east of the Intermountain West too stable and/or dry for thunderstorms. Meanwhile, upstream ridging will shift eastward from the Rockies across the Great Plains. This will occur as a Pacific synoptic trough -- along with a series of accompanying shortwaves and vorticity maxima -- shift inland across the Pacific Coast States from central CA northward. The leading -- and currently strongest -- of the shortwave troughs was apparent in moisture-channel imagery near 135W between about 33N-45N, preceded (as common for such troughs) by a baroclinic-leaf formation on satellite imagery. An associated band of frontogenetic forcing accompanied by a precip band should reach the coastline today. As that occurs -- and especially afterward in cooling air aloft (-20 to -30 deg C) and steepening low/middle-level lapse rates accompanying the strongest DCVA -- some of the convection may extend into icing layers suitable for lightning production. Isolated thunderstorm potential appears most probable over portions of northern CA and western OR, as well as overnight in the Bitterroots vicinity with columnar cooling/moistening. In each area, around 50-100 J/kg MUCAPE will support the convection. ..Edwards/Kerr.. 12/06/2023 Read more