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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1059 AM CST Mon Nov 13 2023 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the contiguous United States on Tuesday. ...Synopsis... A zone of progressive westerlies and associated mid-level shortwave troughs will reside across the northern tier of states on Tuesday. The primary feature for convective interest will be a weak mid-level trough/low over the lower MS Valley and Gulf of Mexico as it slowly moves east during the period. A surface low initially over the western Gulf of Mexico will develop northeastward to be near the mouth of the MS River by early Wednesday morning. Weak instability will be confined to southeastern LA eastward to Mobile Bay. A few elevated, weak thunderstorms are possible, especially Tuesday night close to the coast. Farther east, a few weak thunderstorms are possible over the southern third of the FL Peninsula, but only weak storm intensity is expected. Elsewhere, surface high pressure will influence weather conditions across much of the Lower 48. ..Smith.. 11/13/2023 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1059 AM CST Mon Nov 13 2023 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... No changes were made to the current D1 Fire Weather Outlook. Morning surface observations show relative humidity around 20 percent with winds gusting around 20-30 mph across eastern Colorado into western Kansas and Nebraska, where Elevated fire weather concerns are expected today. Further drying and warming will continue through the afternoon as dry/warm westerly downslope winds increase and diurnal heating leads to a deepening mixed layer. See previous discussion for more information. ..Thornton.. 11/13/2023 .PREV DISCUSSION... /ISSUED 1253 AM CST Mon Nov 13 2023/ ...Synopsis... Elevated fire weather conditions appear probable this afternoon across parts of the High Plains. Early-morning water-vapor imagery depicts an upper-ridge gradually shifting east from the northern Rockies into the Plains. Although slight surface pressure rises have been noted over the past 6-12 hours along the northern High Plains, the expectation is for steady pressure falls through the day as increasing west/southwest flow aloft drive lee troughing. In response, 15-20 mph westerly winds are expected across eastern WY. Antecedent dry conditions combined with downslope warming/drying and diurnal heating should support widespread RH reductions into the low teens and single digits. Although areas of elevated conditions appear likely, latest fuel guidance continues to suggest that most fuels are only modestly receptive, which limits confidence in the overall fire weather threat. To the southeast into northwest KS and adjacent portions of CO and NE, 15-25 mph southerly winds are expected to the east of the deepening lee trough. Recent surface observations show some degree of moisture return ongoing across the southern Plains, but this will likely be insufficient to offset the influence of diurnal heating/mixing, leading to another day of 15-25% RH values across western KS into NE (though a dry bias is noted in recent HRRR/RAP runs which cast some uncertainty on afternoon RH minimums). Fuel guidance remains somewhat nebulous regarding fuel status, but 30-day rainfall deficits, coupled with dry conditions over the weekend, has likely allowed for sufficient curing of finer fuels across parts of northwest KS/northeast CO. An Elevated risk area is introduced where confidence in receptive fuels should best overlap stronger winds/low RH. ...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 1059 AM CST Mon Nov 13 2023 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... No changes were made to the current D1 Fire Weather Outlook. Morning surface observations show relative humidity around 20 percent with winds gusting around 20-30 mph across eastern Colorado into western Kansas and Nebraska, where Elevated fire weather concerns are expected today. Further drying and warming will continue through the afternoon as dry/warm westerly downslope winds increase and diurnal heating leads to a deepening mixed layer. See previous discussion for more information. ..Thornton.. 11/13/2023 .PREV DISCUSSION... /ISSUED 1253 AM CST Mon Nov 13 2023/ ...Synopsis... Elevated fire weather conditions appear probable this afternoon across parts of the High Plains. Early-morning water-vapor imagery depicts an upper-ridge gradually shifting east from the northern Rockies into the Plains. Although slight surface pressure rises have been noted over the past 6-12 hours along the northern High Plains, the expectation is for steady pressure falls through the day as increasing west/southwest flow aloft drive lee troughing. In response, 15-20 mph westerly winds are expected across eastern WY. Antecedent dry conditions combined with downslope warming/drying and diurnal heating should support widespread RH reductions into the low teens and single digits. Although areas of elevated conditions appear likely, latest fuel guidance continues to suggest that most fuels are only modestly receptive, which limits confidence in the overall fire weather threat. To the southeast into northwest KS and adjacent portions of CO and NE, 15-25 mph southerly winds are expected to the east of the deepening lee trough. Recent surface observations show some degree of moisture return ongoing across the southern Plains, but this will likely be insufficient to offset the influence of diurnal heating/mixing, leading to another day of 15-25% RH values across western KS into NE (though a dry bias is noted in recent HRRR/RAP runs which cast some uncertainty on afternoon RH minimums). Fuel guidance remains somewhat nebulous regarding fuel status, but 30-day rainfall deficits, coupled with dry conditions over the weekend, has likely allowed for sufficient curing of finer fuels across parts of northwest KS/northeast CO. An Elevated risk area is introduced where confidence in receptive fuels should best overlap stronger winds/low RH. ...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 1059 AM CST Mon Nov 13 2023 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... No changes were made to the current D1 Fire Weather Outlook. Morning surface observations show relative humidity around 20 percent with winds gusting around 20-30 mph across eastern Colorado into western Kansas and Nebraska, where Elevated fire weather concerns are expected today. Further drying and warming will continue through the afternoon as dry/warm westerly downslope winds increase and diurnal heating leads to a deepening mixed layer. See previous discussion for more information. ..Thornton.. 11/13/2023 .PREV DISCUSSION... /ISSUED 1253 AM CST Mon Nov 13 2023/ ...Synopsis... Elevated fire weather conditions appear probable this afternoon across parts of the High Plains. Early-morning water-vapor imagery depicts an upper-ridge gradually shifting east from the northern Rockies into the Plains. Although slight surface pressure rises have been noted over the past 6-12 hours along the northern High Plains, the expectation is for steady pressure falls through the day as increasing west/southwest flow aloft drive lee troughing. In response, 15-20 mph westerly winds are expected across eastern WY. Antecedent dry conditions combined with downslope warming/drying and diurnal heating should support widespread RH reductions into the low teens and single digits. Although areas of elevated conditions appear likely, latest fuel guidance continues to suggest that most fuels are only modestly receptive, which limits confidence in the overall fire weather threat. To the southeast into northwest KS and adjacent portions of CO and NE, 15-25 mph southerly winds are expected to the east of the deepening lee trough. Recent surface observations show some degree of moisture return ongoing across the southern Plains, but this will likely be insufficient to offset the influence of diurnal heating/mixing, leading to another day of 15-25% RH values across western KS into NE (though a dry bias is noted in recent HRRR/RAP runs which cast some uncertainty on afternoon RH minimums). Fuel guidance remains somewhat nebulous regarding fuel status, but 30-day rainfall deficits, coupled with dry conditions over the weekend, has likely allowed for sufficient curing of finer fuels across parts of northwest KS/northeast CO. An Elevated risk area is introduced where confidence in receptive fuels should best overlap stronger winds/low RH. ...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 1059 AM CST Mon Nov 13 2023 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... No changes were made to the current D1 Fire Weather Outlook. Morning surface observations show relative humidity around 20 percent with winds gusting around 20-30 mph across eastern Colorado into western Kansas and Nebraska, where Elevated fire weather concerns are expected today. Further drying and warming will continue through the afternoon as dry/warm westerly downslope winds increase and diurnal heating leads to a deepening mixed layer. See previous discussion for more information. ..Thornton.. 11/13/2023 .PREV DISCUSSION... /ISSUED 1253 AM CST Mon Nov 13 2023/ ...Synopsis... Elevated fire weather conditions appear probable this afternoon across parts of the High Plains. Early-morning water-vapor imagery depicts an upper-ridge gradually shifting east from the northern Rockies into the Plains. Although slight surface pressure rises have been noted over the past 6-12 hours along the northern High Plains, the expectation is for steady pressure falls through the day as increasing west/southwest flow aloft drive lee troughing. In response, 15-20 mph westerly winds are expected across eastern WY. Antecedent dry conditions combined with downslope warming/drying and diurnal heating should support widespread RH reductions into the low teens and single digits. Although areas of elevated conditions appear likely, latest fuel guidance continues to suggest that most fuels are only modestly receptive, which limits confidence in the overall fire weather threat. To the southeast into northwest KS and adjacent portions of CO and NE, 15-25 mph southerly winds are expected to the east of the deepening lee trough. Recent surface observations show some degree of moisture return ongoing across the southern Plains, but this will likely be insufficient to offset the influence of diurnal heating/mixing, leading to another day of 15-25% RH values across western KS into NE (though a dry bias is noted in recent HRRR/RAP runs which cast some uncertainty on afternoon RH minimums). Fuel guidance remains somewhat nebulous regarding fuel status, but 30-day rainfall deficits, coupled with dry conditions over the weekend, has likely allowed for sufficient curing of finer fuels across parts of northwest KS/northeast CO. An Elevated risk area is introduced where confidence in receptive fuels should best overlap stronger winds/low RH. ...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 1059 AM CST Mon Nov 13 2023 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... No changes were made to the current D1 Fire Weather Outlook. Morning surface observations show relative humidity around 20 percent with winds gusting around 20-30 mph across eastern Colorado into western Kansas and Nebraska, where Elevated fire weather concerns are expected today. Further drying and warming will continue through the afternoon as dry/warm westerly downslope winds increase and diurnal heating leads to a deepening mixed layer. See previous discussion for more information. ..Thornton.. 11/13/2023 .PREV DISCUSSION... /ISSUED 1253 AM CST Mon Nov 13 2023/ ...Synopsis... Elevated fire weather conditions appear probable this afternoon across parts of the High Plains. Early-morning water-vapor imagery depicts an upper-ridge gradually shifting east from the northern Rockies into the Plains. Although slight surface pressure rises have been noted over the past 6-12 hours along the northern High Plains, the expectation is for steady pressure falls through the day as increasing west/southwest flow aloft drive lee troughing. In response, 15-20 mph westerly winds are expected across eastern WY. Antecedent dry conditions combined with downslope warming/drying and diurnal heating should support widespread RH reductions into the low teens and single digits. Although areas of elevated conditions appear likely, latest fuel guidance continues to suggest that most fuels are only modestly receptive, which limits confidence in the overall fire weather threat. To the southeast into northwest KS and adjacent portions of CO and NE, 15-25 mph southerly winds are expected to the east of the deepening lee trough. Recent surface observations show some degree of moisture return ongoing across the southern Plains, but this will likely be insufficient to offset the influence of diurnal heating/mixing, leading to another day of 15-25% RH values across western KS into NE (though a dry bias is noted in recent HRRR/RAP runs which cast some uncertainty on afternoon RH minimums). Fuel guidance remains somewhat nebulous regarding fuel status, but 30-day rainfall deficits, coupled with dry conditions over the weekend, has likely allowed for sufficient curing of finer fuels across parts of northwest KS/northeast CO. An Elevated risk area is introduced where confidence in receptive fuels should best overlap stronger winds/low RH. ...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 0940 AM CST Mon Nov 13 2023 Valid 131630Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis... Upper-ridging, coupled with a surface anticyclone centered over the OH/TN Valleys, will support mass subsidence and static stability across most of the CONUS today, limiting thunderstorm potential. A surface low and associated marginal buoyancy appear to be too far offshore from the lower TX coastline to support a threat for organized thunder, hence the removal of the general thunder line (though a lightning flash or two cannot be ruled out). Modest cooling aloft amid low-topped convection advecting off of Lake Ontario may support enough buoyancy (albeit scant) to support a couple of lightning flashes later today. Otherwise, modest warm-air advection inland across portions of the east-central FL coastline may support an isolated thunderstorm later tonight. ..Squitieri.. 11/13/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0940 AM CST Mon Nov 13 2023 Valid 131630Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis... Upper-ridging, coupled with a surface anticyclone centered over the OH/TN Valleys, will support mass subsidence and static stability across most of the CONUS today, limiting thunderstorm potential. A surface low and associated marginal buoyancy appear to be too far offshore from the lower TX coastline to support a threat for organized thunder, hence the removal of the general thunder line (though a lightning flash or two cannot be ruled out). Modest cooling aloft amid low-topped convection advecting off of Lake Ontario may support enough buoyancy (albeit scant) to support a couple of lightning flashes later today. Otherwise, modest warm-air advection inland across portions of the east-central FL coastline may support an isolated thunderstorm later tonight. ..Squitieri.. 11/13/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0940 AM CST Mon Nov 13 2023 Valid 131630Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis... Upper-ridging, coupled with a surface anticyclone centered over the OH/TN Valleys, will support mass subsidence and static stability across most of the CONUS today, limiting thunderstorm potential. A surface low and associated marginal buoyancy appear to be too far offshore from the lower TX coastline to support a threat for organized thunder, hence the removal of the general thunder line (though a lightning flash or two cannot be ruled out). Modest cooling aloft amid low-topped convection advecting off of Lake Ontario may support enough buoyancy (albeit scant) to support a couple of lightning flashes later today. Otherwise, modest warm-air advection inland across portions of the east-central FL coastline may support an isolated thunderstorm later tonight. ..Squitieri.. 11/13/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0940 AM CST Mon Nov 13 2023 Valid 131630Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis... Upper-ridging, coupled with a surface anticyclone centered over the OH/TN Valleys, will support mass subsidence and static stability across most of the CONUS today, limiting thunderstorm potential. A surface low and associated marginal buoyancy appear to be too far offshore from the lower TX coastline to support a threat for organized thunder, hence the removal of the general thunder line (though a lightning flash or two cannot be ruled out). Modest cooling aloft amid low-topped convection advecting off of Lake Ontario may support enough buoyancy (albeit scant) to support a couple of lightning flashes later today. Otherwise, modest warm-air advection inland across portions of the east-central FL coastline may support an isolated thunderstorm later tonight. ..Squitieri.. 11/13/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0630 AM CST Mon Nov 13 2023 Valid 131300Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along portions of the western/central Gulf Coast, a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis and Discussion... Downstream of a weak mid-level trough over west TX and northern Mexico, a surface front will remain over parts of the western and northern Gulf of Mexico. Convective activity through the period will primarily remain focused along/near the front and offshore of the Gulf Coast. Still, some chance for elevated convection appears possible as the shortwave trough moves eastward across TX through tonight. Showers are ongoing this morning across parts of the FL Atlantic Coast. Poor lapse rates should inhibit most convection from becoming deep enough to support charge separation and lighting. But, an isolated thunderstorm or two may still occur though tonight in weak easterly low-level flow. A strong mid-level jet will move across the Great Lakes and Mid-Atlantic today, with rather cold mid-level temperatures overspreading the Lower Great Lakes. Corresponding steepening of lapse rates over the warmer waters of Lake Ontario and the development of weak instability may allow for isolated lighting flashes with any convection that can develop and move across parts of western NY. ..Gleason.. 11/13/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0630 AM CST Mon Nov 13 2023 Valid 131300Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along portions of the western/central Gulf Coast, a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis and Discussion... Downstream of a weak mid-level trough over west TX and northern Mexico, a surface front will remain over parts of the western and northern Gulf of Mexico. Convective activity through the period will primarily remain focused along/near the front and offshore of the Gulf Coast. Still, some chance for elevated convection appears possible as the shortwave trough moves eastward across TX through tonight. Showers are ongoing this morning across parts of the FL Atlantic Coast. Poor lapse rates should inhibit most convection from becoming deep enough to support charge separation and lighting. But, an isolated thunderstorm or two may still occur though tonight in weak easterly low-level flow. A strong mid-level jet will move across the Great Lakes and Mid-Atlantic today, with rather cold mid-level temperatures overspreading the Lower Great Lakes. Corresponding steepening of lapse rates over the warmer waters of Lake Ontario and the development of weak instability may allow for isolated lighting flashes with any convection that can develop and move across parts of western NY. ..Gleason.. 11/13/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0630 AM CST Mon Nov 13 2023 Valid 131300Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along portions of the western/central Gulf Coast, a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis and Discussion... Downstream of a weak mid-level trough over west TX and northern Mexico, a surface front will remain over parts of the western and northern Gulf of Mexico. Convective activity through the period will primarily remain focused along/near the front and offshore of the Gulf Coast. Still, some chance for elevated convection appears possible as the shortwave trough moves eastward across TX through tonight. Showers are ongoing this morning across parts of the FL Atlantic Coast. Poor lapse rates should inhibit most convection from becoming deep enough to support charge separation and lighting. But, an isolated thunderstorm or two may still occur though tonight in weak easterly low-level flow. A strong mid-level jet will move across the Great Lakes and Mid-Atlantic today, with rather cold mid-level temperatures overspreading the Lower Great Lakes. Corresponding steepening of lapse rates over the warmer waters of Lake Ontario and the development of weak instability may allow for isolated lighting flashes with any convection that can develop and move across parts of western NY. ..Gleason.. 11/13/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0630 AM CST Mon Nov 13 2023 Valid 131300Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along portions of the western/central Gulf Coast, a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis and Discussion... Downstream of a weak mid-level trough over west TX and northern Mexico, a surface front will remain over parts of the western and northern Gulf of Mexico. Convective activity through the period will primarily remain focused along/near the front and offshore of the Gulf Coast. Still, some chance for elevated convection appears possible as the shortwave trough moves eastward across TX through tonight. Showers are ongoing this morning across parts of the FL Atlantic Coast. Poor lapse rates should inhibit most convection from becoming deep enough to support charge separation and lighting. But, an isolated thunderstorm or two may still occur though tonight in weak easterly low-level flow. A strong mid-level jet will move across the Great Lakes and Mid-Atlantic today, with rather cold mid-level temperatures overspreading the Lower Great Lakes. Corresponding steepening of lapse rates over the warmer waters of Lake Ontario and the development of weak instability may allow for isolated lighting flashes with any convection that can develop and move across parts of western NY. ..Gleason.. 11/13/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0630 AM CST Mon Nov 13 2023 Valid 131300Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms appear possible along portions of the western/central Gulf Coast, a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Synopsis and Discussion... Downstream of a weak mid-level trough over west TX and northern Mexico, a surface front will remain over parts of the western and northern Gulf of Mexico. Convective activity through the period will primarily remain focused along/near the front and offshore of the Gulf Coast. Still, some chance for elevated convection appears possible as the shortwave trough moves eastward across TX through tonight. Showers are ongoing this morning across parts of the FL Atlantic Coast. Poor lapse rates should inhibit most convection from becoming deep enough to support charge separation and lighting. But, an isolated thunderstorm or two may still occur though tonight in weak easterly low-level flow. A strong mid-level jet will move across the Great Lakes and Mid-Atlantic today, with rather cold mid-level temperatures overspreading the Lower Great Lakes. Corresponding steepening of lapse rates over the warmer waters of Lake Ontario and the development of weak instability may allow for isolated lighting flashes with any convection that can develop and move across parts of western NY. ..Gleason.. 11/13/2023 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0343 AM CST Mon Nov 13 2023 Valid 161200Z - 211200Z ...DISCUSSION... As the southern-stream mid/upper-level trough discussed in the day-2 and day-3 outlooks approaches FL day 4, with a frontal zone moving slowly northward over portions of the peninsula, thunder potential should increase. However, deep shear and low-level lift each appear on the low part of the spectrum, suggesting any severe potential near the front would be conditional and probably marginal. The shortwave trough should pass FL thereafter. A cut-off cyclone should remain off the CA Coast into day 5/18th-19th, before height falls to the north and northwest encourage inland movement. Progs thereafter show great variability in the amplitude and geometry of this system as it moves across the southwestern and eventually south-central CONUS. Meanwhile, low-level ridging within a slowly modifying continental/polar air mass will prevail over the south-central CONUS, east of or beneath 500-mb anticyclonic flow, through at least most of day 5. This should preclude favorable moisture return for severe potential ahead of the Pacific perturbation. The stronger, more-favorable ECMWF, along with a small minority of GEFS members that are in closest mid/upper pattern agreement with it, indicate some severe potential may develop over the south-central CONUS day 6/19th-20th or day 7/20th-21st, then shift eastward into the Southeast thereafter. At this time, too much spread exists in guidance to outline specific 15% unconditional severe area(s). Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0343 AM CST Mon Nov 13 2023 Valid 161200Z - 211200Z ...DISCUSSION... As the southern-stream mid/upper-level trough discussed in the day-2 and day-3 outlooks approaches FL day 4, with a frontal zone moving slowly northward over portions of the peninsula, thunder potential should increase. However, deep shear and low-level lift each appear on the low part of the spectrum, suggesting any severe potential near the front would be conditional and probably marginal. The shortwave trough should pass FL thereafter. A cut-off cyclone should remain off the CA Coast into day 5/18th-19th, before height falls to the north and northwest encourage inland movement. Progs thereafter show great variability in the amplitude and geometry of this system as it moves across the southwestern and eventually south-central CONUS. Meanwhile, low-level ridging within a slowly modifying continental/polar air mass will prevail over the south-central CONUS, east of or beneath 500-mb anticyclonic flow, through at least most of day 5. This should preclude favorable moisture return for severe potential ahead of the Pacific perturbation. The stronger, more-favorable ECMWF, along with a small minority of GEFS members that are in closest mid/upper pattern agreement with it, indicate some severe potential may develop over the south-central CONUS day 6/19th-20th or day 7/20th-21st, then shift eastward into the Southeast thereafter. At this time, too much spread exists in guidance to outline specific 15% unconditional severe area(s). Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0343 AM CST Mon Nov 13 2023 Valid 161200Z - 211200Z ...DISCUSSION... As the southern-stream mid/upper-level trough discussed in the day-2 and day-3 outlooks approaches FL day 4, with a frontal zone moving slowly northward over portions of the peninsula, thunder potential should increase. However, deep shear and low-level lift each appear on the low part of the spectrum, suggesting any severe potential near the front would be conditional and probably marginal. The shortwave trough should pass FL thereafter. A cut-off cyclone should remain off the CA Coast into day 5/18th-19th, before height falls to the north and northwest encourage inland movement. Progs thereafter show great variability in the amplitude and geometry of this system as it moves across the southwestern and eventually south-central CONUS. Meanwhile, low-level ridging within a slowly modifying continental/polar air mass will prevail over the south-central CONUS, east of or beneath 500-mb anticyclonic flow, through at least most of day 5. This should preclude favorable moisture return for severe potential ahead of the Pacific perturbation. The stronger, more-favorable ECMWF, along with a small minority of GEFS members that are in closest mid/upper pattern agreement with it, indicate some severe potential may develop over the south-central CONUS day 6/19th-20th or day 7/20th-21st, then shift eastward into the Southeast thereafter. At this time, too much spread exists in guidance to outline specific 15% unconditional severe area(s). Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0343 AM CST Mon Nov 13 2023 Valid 161200Z - 211200Z ...DISCUSSION... As the southern-stream mid/upper-level trough discussed in the day-2 and day-3 outlooks approaches FL day 4, with a frontal zone moving slowly northward over portions of the peninsula, thunder potential should increase. However, deep shear and low-level lift each appear on the low part of the spectrum, suggesting any severe potential near the front would be conditional and probably marginal. The shortwave trough should pass FL thereafter. A cut-off cyclone should remain off the CA Coast into day 5/18th-19th, before height falls to the north and northwest encourage inland movement. Progs thereafter show great variability in the amplitude and geometry of this system as it moves across the southwestern and eventually south-central CONUS. Meanwhile, low-level ridging within a slowly modifying continental/polar air mass will prevail over the south-central CONUS, east of or beneath 500-mb anticyclonic flow, through at least most of day 5. This should preclude favorable moisture return for severe potential ahead of the Pacific perturbation. The stronger, more-favorable ECMWF, along with a small minority of GEFS members that are in closest mid/upper pattern agreement with it, indicate some severe potential may develop over the south-central CONUS day 6/19th-20th or day 7/20th-21st, then shift eastward into the Southeast thereafter. At this time, too much spread exists in guidance to outline specific 15% unconditional severe area(s). Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0343 AM CST Mon Nov 13 2023 Valid 161200Z - 211200Z ...DISCUSSION... As the southern-stream mid/upper-level trough discussed in the day-2 and day-3 outlooks approaches FL day 4, with a frontal zone moving slowly northward over portions of the peninsula, thunder potential should increase. However, deep shear and low-level lift each appear on the low part of the spectrum, suggesting any severe potential near the front would be conditional and probably marginal. The shortwave trough should pass FL thereafter. A cut-off cyclone should remain off the CA Coast into day 5/18th-19th, before height falls to the north and northwest encourage inland movement. Progs thereafter show great variability in the amplitude and geometry of this system as it moves across the southwestern and eventually south-central CONUS. Meanwhile, low-level ridging within a slowly modifying continental/polar air mass will prevail over the south-central CONUS, east of or beneath 500-mb anticyclonic flow, through at least most of day 5. This should preclude favorable moisture return for severe potential ahead of the Pacific perturbation. The stronger, more-favorable ECMWF, along with a small minority of GEFS members that are in closest mid/upper pattern agreement with it, indicate some severe potential may develop over the south-central CONUS day 6/19th-20th or day 7/20th-21st, then shift eastward into the Southeast thereafter. At this time, too much spread exists in guidance to outline specific 15% unconditional severe area(s). Read more