Severe Storms

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0114 AM CST Mon Nov 13 2023 Valid 141200Z - 151200Z ...NO CRITICAL AREAS... ...Synopsis... Fire weather concerns appear limited for Tuesday across the country. A lee trough will likely be in place along the northern to central High Plains at the start of the period, and is forecast to migrate east through the day in tandem with a passing upper-level impulse along the U.S./Canada border. A dry air mass will likely overspread the central Plains ahead of the trough, but winds should remain modest given a slow reduction of the regional pressure gradient through the afternoon. Breezy downslope winds may persist across eastern WY during the morning hours, but should slowly diminish through late afternoon as the trough shifts east. While an hour or two of elevated fire weather conditions appears probable during the early afternoon hours, the offset of peak winds from diurnal RH minimums limits confidence in the overall duration of fire weather conditions. This idea is reflected in recent ensemble guidance, which shows the best signal for elevated conditions across southeast WY for a couple of hours early Tuesday afternoon. ..Moore.. 11/13/2023 ...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 0114 AM CST Mon Nov 13 2023 Valid 141200Z - 151200Z ...NO CRITICAL AREAS... ...Synopsis... Fire weather concerns appear limited for Tuesday across the country. A lee trough will likely be in place along the northern to central High Plains at the start of the period, and is forecast to migrate east through the day in tandem with a passing upper-level impulse along the U.S./Canada border. A dry air mass will likely overspread the central Plains ahead of the trough, but winds should remain modest given a slow reduction of the regional pressure gradient through the afternoon. Breezy downslope winds may persist across eastern WY during the morning hours, but should slowly diminish through late afternoon as the trough shifts east. While an hour or two of elevated fire weather conditions appears probable during the early afternoon hours, the offset of peak winds from diurnal RH minimums limits confidence in the overall duration of fire weather conditions. This idea is reflected in recent ensemble guidance, which shows the best signal for elevated conditions across southeast WY for a couple of hours early Tuesday afternoon. ..Moore.. 11/13/2023 ...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 0114 AM CST Mon Nov 13 2023 Valid 141200Z - 151200Z ...NO CRITICAL AREAS... ...Synopsis... Fire weather concerns appear limited for Tuesday across the country. A lee trough will likely be in place along the northern to central High Plains at the start of the period, and is forecast to migrate east through the day in tandem with a passing upper-level impulse along the U.S./Canada border. A dry air mass will likely overspread the central Plains ahead of the trough, but winds should remain modest given a slow reduction of the regional pressure gradient through the afternoon. Breezy downslope winds may persist across eastern WY during the morning hours, but should slowly diminish through late afternoon as the trough shifts east. While an hour or two of elevated fire weather conditions appears probable during the early afternoon hours, the offset of peak winds from diurnal RH minimums limits confidence in the overall duration of fire weather conditions. This idea is reflected in recent ensemble guidance, which shows the best signal for elevated conditions across southeast WY for a couple of hours early Tuesday afternoon. ..Moore.. 11/13/2023 ...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 0114 AM CST Mon Nov 13 2023 Valid 141200Z - 151200Z ...NO CRITICAL AREAS... ...Synopsis... Fire weather concerns appear limited for Tuesday across the country. A lee trough will likely be in place along the northern to central High Plains at the start of the period, and is forecast to migrate east through the day in tandem with a passing upper-level impulse along the U.S./Canada border. A dry air mass will likely overspread the central Plains ahead of the trough, but winds should remain modest given a slow reduction of the regional pressure gradient through the afternoon. Breezy downslope winds may persist across eastern WY during the morning hours, but should slowly diminish through late afternoon as the trough shifts east. While an hour or two of elevated fire weather conditions appears probable during the early afternoon hours, the offset of peak winds from diurnal RH minimums limits confidence in the overall duration of fire weather conditions. This idea is reflected in recent ensemble guidance, which shows the best signal for elevated conditions across southeast WY for a couple of hours early Tuesday afternoon. ..Moore.. 11/13/2023 ...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 1253 AM CST Mon Nov 13 2023 Valid 131200Z - 141200Z ...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. ..Moore.. 11/13/2023 ...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 1253 AM CST Mon Nov 13 2023 Valid 131200Z - 141200Z ...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. ..Moore.. 11/13/2023 ...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 1253 AM CST Mon Nov 13 2023 Valid 131200Z - 141200Z ...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. ..Moore.. 11/13/2023 ...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 1253 AM CST Mon Nov 13 2023 Valid 131200Z - 141200Z ...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. ..Moore.. 11/13/2023 ...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 1253 AM CST Mon Nov 13 2023 Valid 131200Z - 141200Z ...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. ..Moore.. 11/13/2023 ...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 1253 AM CST Mon Nov 13 2023 Valid 131200Z - 141200Z ...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. ..Moore.. 11/13/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CST Mon Nov 13 2023 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Non-severe thunderstorms are possible from portions of the upper Texas coast to southern Louisiana and coastal Mississippi. ...Synopsis/Discussion... In mid/upper levels, a mean trough will be maintained through day 2 off the West Coast, but with a split-flow configuration developing day 1, as a cyclone breaks southward off the one now located over and westward from the BC coastline. The northern-stream portion will move eastward over BC and the Canadian Rockies as an open-wave trough, while the basal cyclone digs southward and becomes cut off well west of CA. By this period, a series of northern-stream shortwave troughs across western and central Canada will render a regime of progressive ridging, moving eastward from the upper Mississippi Valley across the Great Lakes to the northern Appalachians. Farther south, a shortwave trough was apparent in moisture-channel imagery over Chihuahua. As heights fall across the central/northern Plains from the northern-stream perturbations, the southern-stream trough is forecast to move eastward to northwest, central and south-central TX by the start of day-2, 14/12Z. It then should proceed eastward, maintaining nearly neutral tilt, and reaching from northern LA to the west-central Gulf by 15/12Z. Cyclogenesis in low/middle levels (surface-700 mb) is forecast in response over the northwestern Gulf, including a frontal-wave surface low that should move eastward while remaining offshore from TX and LA. The surface warm front likewise should stay south of the coast, though conditional on precip effects to its north, the boundary may impinge on the area near the mouth of the Mississippi River overnight. An extensive warm-advection/moisture-transport regime northeast of the low will spread/expand eastward through the period. The related increase of low-level theta-e north of the front should offset modest mid/upper-level lapse rates enough to foster around 100-500 J/kg MUCAPE over coastal areas, extending into icing layers suitable for lightning. Overall overland thunderstorm coverage appears isolated to widely scattered in this scenario. ..Edwards.. 11/13/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CST Mon Nov 13 2023 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Non-severe thunderstorms are possible from portions of the upper Texas coast to southern Louisiana and coastal Mississippi. ...Synopsis/Discussion... In mid/upper levels, a mean trough will be maintained through day 2 off the West Coast, but with a split-flow configuration developing day 1, as a cyclone breaks southward off the one now located over and westward from the BC coastline. The northern-stream portion will move eastward over BC and the Canadian Rockies as an open-wave trough, while the basal cyclone digs southward and becomes cut off well west of CA. By this period, a series of northern-stream shortwave troughs across western and central Canada will render a regime of progressive ridging, moving eastward from the upper Mississippi Valley across the Great Lakes to the northern Appalachians. Farther south, a shortwave trough was apparent in moisture-channel imagery over Chihuahua. As heights fall across the central/northern Plains from the northern-stream perturbations, the southern-stream trough is forecast to move eastward to northwest, central and south-central TX by the start of day-2, 14/12Z. It then should proceed eastward, maintaining nearly neutral tilt, and reaching from northern LA to the west-central Gulf by 15/12Z. Cyclogenesis in low/middle levels (surface-700 mb) is forecast in response over the northwestern Gulf, including a frontal-wave surface low that should move eastward while remaining offshore from TX and LA. The surface warm front likewise should stay south of the coast, though conditional on precip effects to its north, the boundary may impinge on the area near the mouth of the Mississippi River overnight. An extensive warm-advection/moisture-transport regime northeast of the low will spread/expand eastward through the period. The related increase of low-level theta-e north of the front should offset modest mid/upper-level lapse rates enough to foster around 100-500 J/kg MUCAPE over coastal areas, extending into icing layers suitable for lightning. Overall overland thunderstorm coverage appears isolated to widely scattered in this scenario. ..Edwards.. 11/13/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CST Mon Nov 13 2023 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Non-severe thunderstorms are possible from portions of the upper Texas coast to southern Louisiana and coastal Mississippi. ...Synopsis/Discussion... In mid/upper levels, a mean trough will be maintained through day 2 off the West Coast, but with a split-flow configuration developing day 1, as a cyclone breaks southward off the one now located over and westward from the BC coastline. The northern-stream portion will move eastward over BC and the Canadian Rockies as an open-wave trough, while the basal cyclone digs southward and becomes cut off well west of CA. By this period, a series of northern-stream shortwave troughs across western and central Canada will render a regime of progressive ridging, moving eastward from the upper Mississippi Valley across the Great Lakes to the northern Appalachians. Farther south, a shortwave trough was apparent in moisture-channel imagery over Chihuahua. As heights fall across the central/northern Plains from the northern-stream perturbations, the southern-stream trough is forecast to move eastward to northwest, central and south-central TX by the start of day-2, 14/12Z. It then should proceed eastward, maintaining nearly neutral tilt, and reaching from northern LA to the west-central Gulf by 15/12Z. Cyclogenesis in low/middle levels (surface-700 mb) is forecast in response over the northwestern Gulf, including a frontal-wave surface low that should move eastward while remaining offshore from TX and LA. The surface warm front likewise should stay south of the coast, though conditional on precip effects to its north, the boundary may impinge on the area near the mouth of the Mississippi River overnight. An extensive warm-advection/moisture-transport regime northeast of the low will spread/expand eastward through the period. The related increase of low-level theta-e north of the front should offset modest mid/upper-level lapse rates enough to foster around 100-500 J/kg MUCAPE over coastal areas, extending into icing layers suitable for lightning. Overall overland thunderstorm coverage appears isolated to widely scattered in this scenario. ..Edwards.. 11/13/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CST Mon Nov 13 2023 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Non-severe thunderstorms are possible from portions of the upper Texas coast to southern Louisiana and coastal Mississippi. ...Synopsis/Discussion... In mid/upper levels, a mean trough will be maintained through day 2 off the West Coast, but with a split-flow configuration developing day 1, as a cyclone breaks southward off the one now located over and westward from the BC coastline. The northern-stream portion will move eastward over BC and the Canadian Rockies as an open-wave trough, while the basal cyclone digs southward and becomes cut off well west of CA. By this period, a series of northern-stream shortwave troughs across western and central Canada will render a regime of progressive ridging, moving eastward from the upper Mississippi Valley across the Great Lakes to the northern Appalachians. Farther south, a shortwave trough was apparent in moisture-channel imagery over Chihuahua. As heights fall across the central/northern Plains from the northern-stream perturbations, the southern-stream trough is forecast to move eastward to northwest, central and south-central TX by the start of day-2, 14/12Z. It then should proceed eastward, maintaining nearly neutral tilt, and reaching from northern LA to the west-central Gulf by 15/12Z. Cyclogenesis in low/middle levels (surface-700 mb) is forecast in response over the northwestern Gulf, including a frontal-wave surface low that should move eastward while remaining offshore from TX and LA. The surface warm front likewise should stay south of the coast, though conditional on precip effects to its north, the boundary may impinge on the area near the mouth of the Mississippi River overnight. An extensive warm-advection/moisture-transport regime northeast of the low will spread/expand eastward through the period. The related increase of low-level theta-e north of the front should offset modest mid/upper-level lapse rates enough to foster around 100-500 J/kg MUCAPE over coastal areas, extending into icing layers suitable for lightning. Overall overland thunderstorm coverage appears isolated to widely scattered in this scenario. ..Edwards.. 11/13/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CST Mon Nov 13 2023 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Non-severe thunderstorms are possible from portions of the upper Texas coast to southern Louisiana and coastal Mississippi. ...Synopsis/Discussion... In mid/upper levels, a mean trough will be maintained through day 2 off the West Coast, but with a split-flow configuration developing day 1, as a cyclone breaks southward off the one now located over and westward from the BC coastline. The northern-stream portion will move eastward over BC and the Canadian Rockies as an open-wave trough, while the basal cyclone digs southward and becomes cut off well west of CA. By this period, a series of northern-stream shortwave troughs across western and central Canada will render a regime of progressive ridging, moving eastward from the upper Mississippi Valley across the Great Lakes to the northern Appalachians. Farther south, a shortwave trough was apparent in moisture-channel imagery over Chihuahua. As heights fall across the central/northern Plains from the northern-stream perturbations, the southern-stream trough is forecast to move eastward to northwest, central and south-central TX by the start of day-2, 14/12Z. It then should proceed eastward, maintaining nearly neutral tilt, and reaching from northern LA to the west-central Gulf by 15/12Z. Cyclogenesis in low/middle levels (surface-700 mb) is forecast in response over the northwestern Gulf, including a frontal-wave surface low that should move eastward while remaining offshore from TX and LA. The surface warm front likewise should stay south of the coast, though conditional on precip effects to its north, the boundary may impinge on the area near the mouth of the Mississippi River overnight. An extensive warm-advection/moisture-transport regime northeast of the low will spread/expand eastward through the period. The related increase of low-level theta-e north of the front should offset modest mid/upper-level lapse rates enough to foster around 100-500 J/kg MUCAPE over coastal areas, extending into icing layers suitable for lightning. Overall overland thunderstorm coverage appears isolated to widely scattered in this scenario. ..Edwards.. 11/13/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CST Mon Nov 13 2023 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Non-severe thunderstorms are possible from portions of the upper Texas coast to southern Louisiana and coastal Mississippi. ...Synopsis/Discussion... In mid/upper levels, a mean trough will be maintained through day 2 off the West Coast, but with a split-flow configuration developing day 1, as a cyclone breaks southward off the one now located over and westward from the BC coastline. The northern-stream portion will move eastward over BC and the Canadian Rockies as an open-wave trough, while the basal cyclone digs southward and becomes cut off well west of CA. By this period, a series of northern-stream shortwave troughs across western and central Canada will render a regime of progressive ridging, moving eastward from the upper Mississippi Valley across the Great Lakes to the northern Appalachians. Farther south, a shortwave trough was apparent in moisture-channel imagery over Chihuahua. As heights fall across the central/northern Plains from the northern-stream perturbations, the southern-stream trough is forecast to move eastward to northwest, central and south-central TX by the start of day-2, 14/12Z. It then should proceed eastward, maintaining nearly neutral tilt, and reaching from northern LA to the west-central Gulf by 15/12Z. Cyclogenesis in low/middle levels (surface-700 mb) is forecast in response over the northwestern Gulf, including a frontal-wave surface low that should move eastward while remaining offshore from TX and LA. The surface warm front likewise should stay south of the coast, though conditional on precip effects to its north, the boundary may impinge on the area near the mouth of the Mississippi River overnight. An extensive warm-advection/moisture-transport regime northeast of the low will spread/expand eastward through the period. The related increase of low-level theta-e north of the front should offset modest mid/upper-level lapse rates enough to foster around 100-500 J/kg MUCAPE over coastal areas, extending into icing layers suitable for lightning. Overall overland thunderstorm coverage appears isolated to widely scattered in this scenario. ..Edwards.. 11/13/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1125 PM CST Sun Nov 12 2023 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible along portions of the western/central Gulf Coast, a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Southern US... Northern Mexico short-wave trough is forecast to eject into west TX by 14/00z, but a weaker low-amplitude short-wave trough may precede this feature, at a lower latitude, ensuring the main surface low holds off the TX Coast. Latest model guidance maintains the primary surface baroclinic zone offshore through the period. Late this evening, organized convection is noted along this boundary, roughly 50 miles east of Padre Island. As a result, the primary focus for organized thunderstorms will remain just offshore. However, elevated convection should evolve within a warm advection corridor from the coastal Plain of TX into the LA Gulf Coastal region where forecast buoyancy supports lightning. Downstream, weak showers are currently moving inland along the central FL Atlantic Coast. Forecast soundings maintain weak buoyancy through the period as roughly 3km deep easterly flow will persist Monday. Some of the deeper updrafts may generate lightning, but overall this activity should remain isolated. ...Lower Great Lakes... Strong 500mb speed max will translate southeast across lower MI into central PA by late afternoon which will allow much cooler temperatures to spread across the lower Great Lakes. Lapse rates will steepen significantly as this occurs and weak buoyancy will develop over the warmer waters of Lake Ontario. Some risk for lightning will be noted with convection across this region. ..Darrow/Moore.. 11/13/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1125 PM CST Sun Nov 12 2023 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible along portions of the western/central Gulf Coast, a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Southern US... Northern Mexico short-wave trough is forecast to eject into west TX by 14/00z, but a weaker low-amplitude short-wave trough may precede this feature, at a lower latitude, ensuring the main surface low holds off the TX Coast. Latest model guidance maintains the primary surface baroclinic zone offshore through the period. Late this evening, organized convection is noted along this boundary, roughly 50 miles east of Padre Island. As a result, the primary focus for organized thunderstorms will remain just offshore. However, elevated convection should evolve within a warm advection corridor from the coastal Plain of TX into the LA Gulf Coastal region where forecast buoyancy supports lightning. Downstream, weak showers are currently moving inland along the central FL Atlantic Coast. Forecast soundings maintain weak buoyancy through the period as roughly 3km deep easterly flow will persist Monday. Some of the deeper updrafts may generate lightning, but overall this activity should remain isolated. ...Lower Great Lakes... Strong 500mb speed max will translate southeast across lower MI into central PA by late afternoon which will allow much cooler temperatures to spread across the lower Great Lakes. Lapse rates will steepen significantly as this occurs and weak buoyancy will develop over the warmer waters of Lake Ontario. Some risk for lightning will be noted with convection across this region. ..Darrow/Moore.. 11/13/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1125 PM CST Sun Nov 12 2023 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible along portions of the western/central Gulf Coast, a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Southern US... Northern Mexico short-wave trough is forecast to eject into west TX by 14/00z, but a weaker low-amplitude short-wave trough may precede this feature, at a lower latitude, ensuring the main surface low holds off the TX Coast. Latest model guidance maintains the primary surface baroclinic zone offshore through the period. Late this evening, organized convection is noted along this boundary, roughly 50 miles east of Padre Island. As a result, the primary focus for organized thunderstorms will remain just offshore. However, elevated convection should evolve within a warm advection corridor from the coastal Plain of TX into the LA Gulf Coastal region where forecast buoyancy supports lightning. Downstream, weak showers are currently moving inland along the central FL Atlantic Coast. Forecast soundings maintain weak buoyancy through the period as roughly 3km deep easterly flow will persist Monday. Some of the deeper updrafts may generate lightning, but overall this activity should remain isolated. ...Lower Great Lakes... Strong 500mb speed max will translate southeast across lower MI into central PA by late afternoon which will allow much cooler temperatures to spread across the lower Great Lakes. Lapse rates will steepen significantly as this occurs and weak buoyancy will develop over the warmer waters of Lake Ontario. Some risk for lightning will be noted with convection across this region. ..Darrow/Moore.. 11/13/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1125 PM CST Sun Nov 12 2023 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are possible along portions of the western/central Gulf Coast, a small part of the Florida Atlantic Coast, and in the lee of Lake Ontario. ...Southern US... Northern Mexico short-wave trough is forecast to eject into west TX by 14/00z, but a weaker low-amplitude short-wave trough may precede this feature, at a lower latitude, ensuring the main surface low holds off the TX Coast. Latest model guidance maintains the primary surface baroclinic zone offshore through the period. Late this evening, organized convection is noted along this boundary, roughly 50 miles east of Padre Island. As a result, the primary focus for organized thunderstorms will remain just offshore. However, elevated convection should evolve within a warm advection corridor from the coastal Plain of TX into the LA Gulf Coastal region where forecast buoyancy supports lightning. Downstream, weak showers are currently moving inland along the central FL Atlantic Coast. Forecast soundings maintain weak buoyancy through the period as roughly 3km deep easterly flow will persist Monday. Some of the deeper updrafts may generate lightning, but overall this activity should remain isolated. ...Lower Great Lakes... Strong 500mb speed max will translate southeast across lower MI into central PA by late afternoon which will allow much cooler temperatures to spread across the lower Great Lakes. Lapse rates will steepen significantly as this occurs and weak buoyancy will develop over the warmer waters of Lake Ontario. Some risk for lightning will be noted with convection across this region. ..Darrow/Moore.. 11/13/2023 Read more