Severe Storms

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1110 AM CST Thu Dec 07 2023 Valid 081200Z - 091200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS NORTHEAST TX TO AR AND SOUTHERN MO... ...SUMMARY... Isolated severe hail will be possible late night Friday from northeast Texas and southeast Oklahoma through central Arkansas and southwest Missouri. ...Synopsis... Guidance has clearly trended over the past 36 hours to multiple distinct shortwave impulses ejecting within the broad upper trough over the western and central states. The lead impulse in the Four Corners area at 12Z Friday will amplify across the central Great Plains towards the Mid-MS Valley. Meanwhile, a secondary impulse and attendant speed max will hold back within the basal portion of the broad trough over the Four Corners. The net result will be more prominent surface cyclogenesis occurring ahead of the lead wave, mainly on Friday night across the Lower MO Valley towards southern Lake MI. A surface cold front will sweep more rapidly east in vicinity of the cyclone track, and slow its southeast push across the southeast OK/Ark-La-Tex area late in the period. ...Northeast TX to AR/Southern MO... The aforementioned synoptic trends suggest that forcing for ascent appears to be limited across the modifying warm sector from east TX towards the Ozarks on Friday night. Timing of the wave ejections indicate near-neutral mid-level height change is anticipated overnight in this region. With substantial modification necessary of the continental polar air mass that is across the northwest Gulf coast, more than meager surface-based instability will likely struggle to advect north to/beyond the Ozarks. Within a southwesterly low to mid-level flow regime, moderate MLCIN and low RH above the capping inversion suggest that warm-sector thunderstorm initiation ahead of the cold front is unlikely through 12Z Saturday. Low-level warm theta-e advection could still be adequate for isolated slightly elevated thunderstorms centered on the southeast OK/Ark-La-Tex region deeper into AR overnight, with a primary threat of localized severe hail. ..15_ows.. 12/07/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1110 AM CST Thu Dec 07 2023 Valid 081200Z - 091200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS NORTHEAST TX TO AR AND SOUTHERN MO... ...SUMMARY... Isolated severe hail will be possible late night Friday from northeast Texas and southeast Oklahoma through central Arkansas and southwest Missouri. ...Synopsis... Guidance has clearly trended over the past 36 hours to multiple distinct shortwave impulses ejecting within the broad upper trough over the western and central states. The lead impulse in the Four Corners area at 12Z Friday will amplify across the central Great Plains towards the Mid-MS Valley. Meanwhile, a secondary impulse and attendant speed max will hold back within the basal portion of the broad trough over the Four Corners. The net result will be more prominent surface cyclogenesis occurring ahead of the lead wave, mainly on Friday night across the Lower MO Valley towards southern Lake MI. A surface cold front will sweep more rapidly east in vicinity of the cyclone track, and slow its southeast push across the southeast OK/Ark-La-Tex area late in the period. ...Northeast TX to AR/Southern MO... The aforementioned synoptic trends suggest that forcing for ascent appears to be limited across the modifying warm sector from east TX towards the Ozarks on Friday night. Timing of the wave ejections indicate near-neutral mid-level height change is anticipated overnight in this region. With substantial modification necessary of the continental polar air mass that is across the northwest Gulf coast, more than meager surface-based instability will likely struggle to advect north to/beyond the Ozarks. Within a southwesterly low to mid-level flow regime, moderate MLCIN and low RH above the capping inversion suggest that warm-sector thunderstorm initiation ahead of the cold front is unlikely through 12Z Saturday. Low-level warm theta-e advection could still be adequate for isolated slightly elevated thunderstorms centered on the southeast OK/Ark-La-Tex region deeper into AR overnight, with a primary threat of localized severe hail. ..15_ows.. 12/07/2023 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1058 AM CST Thu Dec 07 2023 Valid 071700Z - 081200Z ...NO CRITICAL AREAS... No changes. See previous discussion below. ..Bentley.. 12/07/2023 .PREV DISCUSSION... /ISSUED 1227 AM CST Thu Dec 07 2023/ ...Synopsis... A belt of strong mid-level westerly flow will move across the Rockies today which will result in development of a surface cyclone across central Plains late in the period. 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 and extending as far north as the southeast plains of Colorado. 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 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1058 AM CST Thu Dec 07 2023 Valid 071700Z - 081200Z ...NO CRITICAL AREAS... No changes. See previous discussion below. ..Bentley.. 12/07/2023 .PREV DISCUSSION... /ISSUED 1227 AM CST Thu Dec 07 2023/ ...Synopsis... A belt of strong mid-level westerly flow will move across the Rockies today which will result in development of a surface cyclone across central Plains late in the period. 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 and extending as far north as the southeast plains of Colorado. 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 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1058 AM CST Thu Dec 07 2023 Valid 071700Z - 081200Z ...NO CRITICAL AREAS... No changes. See previous discussion below. ..Bentley.. 12/07/2023 .PREV DISCUSSION... /ISSUED 1227 AM CST Thu Dec 07 2023/ ...Synopsis... A belt of strong mid-level westerly flow will move across the Rockies today which will result in development of a surface cyclone across central Plains late in the period. 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 and extending as far north as the southeast plains of Colorado. 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 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1058 AM CST Thu Dec 07 2023 Valid 071700Z - 081200Z ...NO CRITICAL AREAS... No changes. See previous discussion below. ..Bentley.. 12/07/2023 .PREV DISCUSSION... /ISSUED 1227 AM CST Thu Dec 07 2023/ ...Synopsis... A belt of strong mid-level westerly flow will move across the Rockies today which will result in development of a surface cyclone across central Plains late in the period. 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 and extending as far north as the southeast plains of Colorado. 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 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1058 AM CST Thu Dec 07 2023 Valid 071700Z - 081200Z ...NO CRITICAL AREAS... No changes. See previous discussion below. ..Bentley.. 12/07/2023 .PREV DISCUSSION... /ISSUED 1227 AM CST Thu Dec 07 2023/ ...Synopsis... A belt of strong mid-level westerly flow will move across the Rockies today which will result in development of a surface cyclone across central Plains late in the period. 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 and extending as far north as the southeast plains of Colorado. 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 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1058 AM CST Thu Dec 07 2023 Valid 071700Z - 081200Z ...NO CRITICAL AREAS... No changes. See previous discussion below. ..Bentley.. 12/07/2023 .PREV DISCUSSION... /ISSUED 1227 AM CST Thu Dec 07 2023/ ...Synopsis... A belt of strong mid-level westerly flow will move across the Rockies today which will result in development of a surface cyclone across central Plains late in the period. 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 and extending as far north as the southeast plains of Colorado. 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 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1012 AM CST Thu Dec 07 2023 Valid 071630Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis/Discussion... The mid/upper-level pattern will evolve toward a progressive, high-amplitude western CONUS trough through the period, as associated increasingly cyclonic flow is traversed by a series of shortwaves. Accompanying cold midlevel air (-20 to -34 deg C) 500-mb temperatures will spread eastward/inland across a vast section of the northwestern CONUS through the period, from the northern Great Basin northward, and the central/northern Rockies westward. Mesobeta-scale shots of localized, enhanced large-scale lift, where moving atop pockets of marginally favorable low/middle- level moisture, may prompt transient bursts of shallow cells with very isolated/brief thunder potential, almost anywhere in that swath. However, the most favorable areas for 10% or greater thunderstorm coverage appears to be 1) near-coastal Northwest from northern CA to WA, from portions of the Cascades westward, where the coldest air aloft will overlie the greatest low-level moisture content near its Pacific source, and 2) eastern OR/southwestern ID and vicinity. A strong shortwave trough now nearing the coast has contributed to some lightning offshore and near coastal southwestern OR the last few hours, and that potential should continue and shift inland through the remainder of the morning and afternoon. Another round of potential this evening may accompany a field of ascent preceding a perturbation now well west of Vancouver Island, and progged to dig southeastward toward the northern OR Coast. ..15_ows.. 12/07/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1012 AM CST Thu Dec 07 2023 Valid 071630Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis/Discussion... The mid/upper-level pattern will evolve toward a progressive, high-amplitude western CONUS trough through the period, as associated increasingly cyclonic flow is traversed by a series of shortwaves. Accompanying cold midlevel air (-20 to -34 deg C) 500-mb temperatures will spread eastward/inland across a vast section of the northwestern CONUS through the period, from the northern Great Basin northward, and the central/northern Rockies westward. Mesobeta-scale shots of localized, enhanced large-scale lift, where moving atop pockets of marginally favorable low/middle- level moisture, may prompt transient bursts of shallow cells with very isolated/brief thunder potential, almost anywhere in that swath. However, the most favorable areas for 10% or greater thunderstorm coverage appears to be 1) near-coastal Northwest from northern CA to WA, from portions of the Cascades westward, where the coldest air aloft will overlie the greatest low-level moisture content near its Pacific source, and 2) eastern OR/southwestern ID and vicinity. A strong shortwave trough now nearing the coast has contributed to some lightning offshore and near coastal southwestern OR the last few hours, and that potential should continue and shift inland through the remainder of the morning and afternoon. Another round of potential this evening may accompany a field of ascent preceding a perturbation now well west of Vancouver Island, and progged to dig southeastward toward the northern OR Coast. ..15_ows.. 12/07/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1012 AM CST Thu Dec 07 2023 Valid 071630Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis/Discussion... The mid/upper-level pattern will evolve toward a progressive, high-amplitude western CONUS trough through the period, as associated increasingly cyclonic flow is traversed by a series of shortwaves. Accompanying cold midlevel air (-20 to -34 deg C) 500-mb temperatures will spread eastward/inland across a vast section of the northwestern CONUS through the period, from the northern Great Basin northward, and the central/northern Rockies westward. Mesobeta-scale shots of localized, enhanced large-scale lift, where moving atop pockets of marginally favorable low/middle- level moisture, may prompt transient bursts of shallow cells with very isolated/brief thunder potential, almost anywhere in that swath. However, the most favorable areas for 10% or greater thunderstorm coverage appears to be 1) near-coastal Northwest from northern CA to WA, from portions of the Cascades westward, where the coldest air aloft will overlie the greatest low-level moisture content near its Pacific source, and 2) eastern OR/southwestern ID and vicinity. A strong shortwave trough now nearing the coast has contributed to some lightning offshore and near coastal southwestern OR the last few hours, and that potential should continue and shift inland through the remainder of the morning and afternoon. Another round of potential this evening may accompany a field of ascent preceding a perturbation now well west of Vancouver Island, and progged to dig southeastward toward the northern OR Coast. ..15_ows.. 12/07/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1012 AM CST Thu Dec 07 2023 Valid 071630Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis/Discussion... The mid/upper-level pattern will evolve toward a progressive, high-amplitude western CONUS trough through the period, as associated increasingly cyclonic flow is traversed by a series of shortwaves. Accompanying cold midlevel air (-20 to -34 deg C) 500-mb temperatures will spread eastward/inland across a vast section of the northwestern CONUS through the period, from the northern Great Basin northward, and the central/northern Rockies westward. Mesobeta-scale shots of localized, enhanced large-scale lift, where moving atop pockets of marginally favorable low/middle- level moisture, may prompt transient bursts of shallow cells with very isolated/brief thunder potential, almost anywhere in that swath. However, the most favorable areas for 10% or greater thunderstorm coverage appears to be 1) near-coastal Northwest from northern CA to WA, from portions of the Cascades westward, where the coldest air aloft will overlie the greatest low-level moisture content near its Pacific source, and 2) eastern OR/southwestern ID and vicinity. A strong shortwave trough now nearing the coast has contributed to some lightning offshore and near coastal southwestern OR the last few hours, and that potential should continue and shift inland through the remainder of the morning and afternoon. Another round of potential this evening may accompany a field of ascent preceding a perturbation now well west of Vancouver Island, and progged to dig southeastward toward the northern OR Coast. ..15_ows.. 12/07/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1012 AM CST Thu Dec 07 2023 Valid 071630Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis/Discussion... The mid/upper-level pattern will evolve toward a progressive, high-amplitude western CONUS trough through the period, as associated increasingly cyclonic flow is traversed by a series of shortwaves. Accompanying cold midlevel air (-20 to -34 deg C) 500-mb temperatures will spread eastward/inland across a vast section of the northwestern CONUS through the period, from the northern Great Basin northward, and the central/northern Rockies westward. Mesobeta-scale shots of localized, enhanced large-scale lift, where moving atop pockets of marginally favorable low/middle- level moisture, may prompt transient bursts of shallow cells with very isolated/brief thunder potential, almost anywhere in that swath. However, the most favorable areas for 10% or greater thunderstorm coverage appears to be 1) near-coastal Northwest from northern CA to WA, from portions of the Cascades westward, where the coldest air aloft will overlie the greatest low-level moisture content near its Pacific source, and 2) eastern OR/southwestern ID and vicinity. A strong shortwave trough now nearing the coast has contributed to some lightning offshore and near coastal southwestern OR the last few hours, and that potential should continue and shift inland through the remainder of the morning and afternoon. Another round of potential this evening may accompany a field of ascent preceding a perturbation now well west of Vancouver Island, and progged to dig southeastward toward the northern OR Coast. ..15_ows.. 12/07/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1012 AM CST Thu Dec 07 2023 Valid 071630Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis/Discussion... The mid/upper-level pattern will evolve toward a progressive, high-amplitude western CONUS trough through the period, as associated increasingly cyclonic flow is traversed by a series of shortwaves. Accompanying cold midlevel air (-20 to -34 deg C) 500-mb temperatures will spread eastward/inland across a vast section of the northwestern CONUS through the period, from the northern Great Basin northward, and the central/northern Rockies westward. Mesobeta-scale shots of localized, enhanced large-scale lift, where moving atop pockets of marginally favorable low/middle- level moisture, may prompt transient bursts of shallow cells with very isolated/brief thunder potential, almost anywhere in that swath. However, the most favorable areas for 10% or greater thunderstorm coverage appears to be 1) near-coastal Northwest from northern CA to WA, from portions of the Cascades westward, where the coldest air aloft will overlie the greatest low-level moisture content near its Pacific source, and 2) eastern OR/southwestern ID and vicinity. A strong shortwave trough now nearing the coast has contributed to some lightning offshore and near coastal southwestern OR the last few hours, and that potential should continue and shift inland through the remainder of the morning and afternoon. Another round of potential this evening may accompany a field of ascent preceding a perturbation now well west of Vancouver Island, and progged to dig southeastward toward the northern OR Coast. ..15_ows.. 12/07/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0639 AM CST Thu Dec 07 2023 Valid 071300Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis/Discussion... The mid/upper-level pattern will evolve toward a progressive, high-amplitude western CONUS trough through the period, as associated increasingly cyclonic flow is traversed by a series of shortwaves. Accompanying cold midlevel air (-20 to -34 deg C) 500-mb temperatures will spread eastward/inland across a vast section of the northwestern CONUS through the period, from the northern Great Basin northward, and the central/northern Rockies westward. Mesobeta-scale shots of localized, enhanced large-scale lift, where moving atop pockets of marginally favorable low/middle- level moisture, may prompt transient bursts of shallow cells with very isolated/brief thunder potential, almost anywhere in that swath. However, the most favorable areas for 10% or greater thunderstorm coverage appears to be 1) near-coastal Northwest from northern CA to WA, from portions of the Cascades westward, where the coldest air aloft will overlie the greatest low-level moisture content near its Pacific source, and 2) eastern OR/southwestern ID and vicinity. A strong shortwave trough now nearing the coast has contributed to some lightning offshore and near coastal southwestern OR the last few hours, and that potential should continue and shift inland through the remainder of the morning and afternoon. Another round of potential this evening may accompany a field of ascent preceding a perturbation now well west of Vancouver Island, and progged to dig southeastward toward the northern OR Coast. ..Edwards/Kerr.. 12/07/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0639 AM CST Thu Dec 07 2023 Valid 071300Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis/Discussion... The mid/upper-level pattern will evolve toward a progressive, high-amplitude western CONUS trough through the period, as associated increasingly cyclonic flow is traversed by a series of shortwaves. Accompanying cold midlevel air (-20 to -34 deg C) 500-mb temperatures will spread eastward/inland across a vast section of the northwestern CONUS through the period, from the northern Great Basin northward, and the central/northern Rockies westward. Mesobeta-scale shots of localized, enhanced large-scale lift, where moving atop pockets of marginally favorable low/middle- level moisture, may prompt transient bursts of shallow cells with very isolated/brief thunder potential, almost anywhere in that swath. However, the most favorable areas for 10% or greater thunderstorm coverage appears to be 1) near-coastal Northwest from northern CA to WA, from portions of the Cascades westward, where the coldest air aloft will overlie the greatest low-level moisture content near its Pacific source, and 2) eastern OR/southwestern ID and vicinity. A strong shortwave trough now nearing the coast has contributed to some lightning offshore and near coastal southwestern OR the last few hours, and that potential should continue and shift inland through the remainder of the morning and afternoon. Another round of potential this evening may accompany a field of ascent preceding a perturbation now well west of Vancouver Island, and progged to dig southeastward toward the northern OR Coast. ..Edwards/Kerr.. 12/07/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0639 AM CST Thu Dec 07 2023 Valid 071300Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis/Discussion... The mid/upper-level pattern will evolve toward a progressive, high-amplitude western CONUS trough through the period, as associated increasingly cyclonic flow is traversed by a series of shortwaves. Accompanying cold midlevel air (-20 to -34 deg C) 500-mb temperatures will spread eastward/inland across a vast section of the northwestern CONUS through the period, from the northern Great Basin northward, and the central/northern Rockies westward. Mesobeta-scale shots of localized, enhanced large-scale lift, where moving atop pockets of marginally favorable low/middle- level moisture, may prompt transient bursts of shallow cells with very isolated/brief thunder potential, almost anywhere in that swath. However, the most favorable areas for 10% or greater thunderstorm coverage appears to be 1) near-coastal Northwest from northern CA to WA, from portions of the Cascades westward, where the coldest air aloft will overlie the greatest low-level moisture content near its Pacific source, and 2) eastern OR/southwestern ID and vicinity. A strong shortwave trough now nearing the coast has contributed to some lightning offshore and near coastal southwestern OR the last few hours, and that potential should continue and shift inland through the remainder of the morning and afternoon. Another round of potential this evening may accompany a field of ascent preceding a perturbation now well west of Vancouver Island, and progged to dig southeastward toward the northern OR Coast. ..Edwards/Kerr.. 12/07/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0639 AM CST Thu Dec 07 2023 Valid 071300Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis/Discussion... The mid/upper-level pattern will evolve toward a progressive, high-amplitude western CONUS trough through the period, as associated increasingly cyclonic flow is traversed by a series of shortwaves. Accompanying cold midlevel air (-20 to -34 deg C) 500-mb temperatures will spread eastward/inland across a vast section of the northwestern CONUS through the period, from the northern Great Basin northward, and the central/northern Rockies westward. Mesobeta-scale shots of localized, enhanced large-scale lift, where moving atop pockets of marginally favorable low/middle- level moisture, may prompt transient bursts of shallow cells with very isolated/brief thunder potential, almost anywhere in that swath. However, the most favorable areas for 10% or greater thunderstorm coverage appears to be 1) near-coastal Northwest from northern CA to WA, from portions of the Cascades westward, where the coldest air aloft will overlie the greatest low-level moisture content near its Pacific source, and 2) eastern OR/southwestern ID and vicinity. A strong shortwave trough now nearing the coast has contributed to some lightning offshore and near coastal southwestern OR the last few hours, and that potential should continue and shift inland through the remainder of the morning and afternoon. Another round of potential this evening may accompany a field of ascent preceding a perturbation now well west of Vancouver Island, and progged to dig southeastward toward the northern OR Coast. ..Edwards/Kerr.. 12/07/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0639 AM CST Thu Dec 07 2023 Valid 071300Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis/Discussion... The mid/upper-level pattern will evolve toward a progressive, high-amplitude western CONUS trough through the period, as associated increasingly cyclonic flow is traversed by a series of shortwaves. Accompanying cold midlevel air (-20 to -34 deg C) 500-mb temperatures will spread eastward/inland across a vast section of the northwestern CONUS through the period, from the northern Great Basin northward, and the central/northern Rockies westward. Mesobeta-scale shots of localized, enhanced large-scale lift, where moving atop pockets of marginally favorable low/middle- level moisture, may prompt transient bursts of shallow cells with very isolated/brief thunder potential, almost anywhere in that swath. However, the most favorable areas for 10% or greater thunderstorm coverage appears to be 1) near-coastal Northwest from northern CA to WA, from portions of the Cascades westward, where the coldest air aloft will overlie the greatest low-level moisture content near its Pacific source, and 2) eastern OR/southwestern ID and vicinity. A strong shortwave trough now nearing the coast has contributed to some lightning offshore and near coastal southwestern OR the last few hours, and that potential should continue and shift inland through the remainder of the morning and afternoon. Another round of potential this evening may accompany a field of ascent preceding a perturbation now well west of Vancouver Island, and progged to dig southeastward toward the northern OR Coast. ..Edwards/Kerr.. 12/07/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0639 AM CST Thu Dec 07 2023 Valid 071300Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis/Discussion... The mid/upper-level pattern will evolve toward a progressive, high-amplitude western CONUS trough through the period, as associated increasingly cyclonic flow is traversed by a series of shortwaves. Accompanying cold midlevel air (-20 to -34 deg C) 500-mb temperatures will spread eastward/inland across a vast section of the northwestern CONUS through the period, from the northern Great Basin northward, and the central/northern Rockies westward. Mesobeta-scale shots of localized, enhanced large-scale lift, where moving atop pockets of marginally favorable low/middle- level moisture, may prompt transient bursts of shallow cells with very isolated/brief thunder potential, almost anywhere in that swath. However, the most favorable areas for 10% or greater thunderstorm coverage appears to be 1) near-coastal Northwest from northern CA to WA, from portions of the Cascades westward, where the coldest air aloft will overlie the greatest low-level moisture content near its Pacific source, and 2) eastern OR/southwestern ID and vicinity. A strong shortwave trough now nearing the coast has contributed to some lightning offshore and near coastal southwestern OR the last few hours, and that potential should continue and shift inland through the remainder of the morning and afternoon. Another round of potential this evening may accompany a field of ascent preceding a perturbation now well west of Vancouver Island, and progged to dig southeastward toward the northern OR Coast. ..Edwards/Kerr.. 12/07/2023 Read more