Severe Storms

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Mon Sep 16 2019 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN HIGH PLAINS...AND ACROSS THE MINNESOTA VICINITY LATE... ...SUMMARY... A few strong/severe storms are expected across the northern high Plains area Tuesday afternoon/early evening, and may evolve overnight into the Minnesota vicinity. Hail and locally damaging winds will be possible. ...Synopsis... An amplified upper flow field will persist across the U.S. Tuesday/Day 2, as cyclonic flow prevails over the Northeast U.S. and the western States, flanking a central U.S. ridge. Within the broader western U.S. troughing, a vigorous, negatively tilted lead wave is forecast to eject northeastward across the Intermountain region and into the northern high Plains through the period. Ahead of the aforementioned, ejecting short-wave trough, a cold front is progged to advance quickly across the Rockies and into the high Plains through the afternoon, and then eastward across the northern and central Plains overnight. This front -- and the convection associated with it -- will drive the main area of severe potential across north-central portions of the U.S. on Tuesday. ...Northern high Plains... As the surface cold front advances quickly eastward across the northern High Plains region, scattered showers and thunderstorms are expected to develop during the afternoon -- perhaps as far west as the Bighorns, and then spreading quickly across the high Plains. With somewhat limited CAPE expected, and a substantial dry slot expected to surge eastward across Wyoming and the western Dakotas, severe risk appears likely to remain limited. Still, a few of the strongest storms just ahead of the dry slot -- and perhaps north of the surge over eastern Montana -- may produce locally damaging winds, and marginal hail. ...Minnesota vicinity... While elevated storms are forecast to be ongoing over portions of the upper Mississippi Valley area at the start of the period, any severe risk appears to be limited, and confined to marginal hail, given the anticipated, elevated nature of the storms. Convection should diminish through the morning. Overnight, as the cold front advances across the northern Plains, redevelopment of storms is expected, possibly evolving into a squall line through latter stages of the period. With this said, storms are not expected to be particularly vigorous for the most part, given that stronger flow aloft is expected to lag the surface frontal location, and thus only modest shear is forecast atop the frontal zone. Still, some hail -- and possibly a strong gust or two -- may occur sporadically with stronger updrafts within the evolving convective band. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Goss.. 09/16/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Mon Sep 16 2019 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN HIGH PLAINS...AND ACROSS THE MINNESOTA VICINITY LATE... ...SUMMARY... A few strong/severe storms are expected across the northern high Plains area Tuesday afternoon/early evening, and may evolve overnight into the Minnesota vicinity. Hail and locally damaging winds will be possible. ...Synopsis... An amplified upper flow field will persist across the U.S. Tuesday/Day 2, as cyclonic flow prevails over the Northeast U.S. and the western States, flanking a central U.S. ridge. Within the broader western U.S. troughing, a vigorous, negatively tilted lead wave is forecast to eject northeastward across the Intermountain region and into the northern high Plains through the period. Ahead of the aforementioned, ejecting short-wave trough, a cold front is progged to advance quickly across the Rockies and into the high Plains through the afternoon, and then eastward across the northern and central Plains overnight. This front -- and the convection associated with it -- will drive the main area of severe potential across north-central portions of the U.S. on Tuesday. ...Northern high Plains... As the surface cold front advances quickly eastward across the northern High Plains region, scattered showers and thunderstorms are expected to develop during the afternoon -- perhaps as far west as the Bighorns, and then spreading quickly across the high Plains. With somewhat limited CAPE expected, and a substantial dry slot expected to surge eastward across Wyoming and the western Dakotas, severe risk appears likely to remain limited. Still, a few of the strongest storms just ahead of the dry slot -- and perhaps north of the surge over eastern Montana -- may produce locally damaging winds, and marginal hail. ...Minnesota vicinity... While elevated storms are forecast to be ongoing over portions of the upper Mississippi Valley area at the start of the period, any severe risk appears to be limited, and confined to marginal hail, given the anticipated, elevated nature of the storms. Convection should diminish through the morning. Overnight, as the cold front advances across the northern Plains, redevelopment of storms is expected, possibly evolving into a squall line through latter stages of the period. With this said, storms are not expected to be particularly vigorous for the most part, given that stronger flow aloft is expected to lag the surface frontal location, and thus only modest shear is forecast atop the frontal zone. Still, some hail -- and possibly a strong gust or two -- may occur sporadically with stronger updrafts within the evolving convective band. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Goss.. 09/16/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Mon Sep 16 2019 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN HIGH PLAINS...AND ACROSS THE MINNESOTA VICINITY LATE... ...SUMMARY... A few strong/severe storms are expected across the northern high Plains area Tuesday afternoon/early evening, and may evolve overnight into the Minnesota vicinity. Hail and locally damaging winds will be possible. ...Synopsis... An amplified upper flow field will persist across the U.S. Tuesday/Day 2, as cyclonic flow prevails over the Northeast U.S. and the western States, flanking a central U.S. ridge. Within the broader western U.S. troughing, a vigorous, negatively tilted lead wave is forecast to eject northeastward across the Intermountain region and into the northern high Plains through the period. Ahead of the aforementioned, ejecting short-wave trough, a cold front is progged to advance quickly across the Rockies and into the high Plains through the afternoon, and then eastward across the northern and central Plains overnight. This front -- and the convection associated with it -- will drive the main area of severe potential across north-central portions of the U.S. on Tuesday. ...Northern high Plains... As the surface cold front advances quickly eastward across the northern High Plains region, scattered showers and thunderstorms are expected to develop during the afternoon -- perhaps as far west as the Bighorns, and then spreading quickly across the high Plains. With somewhat limited CAPE expected, and a substantial dry slot expected to surge eastward across Wyoming and the western Dakotas, severe risk appears likely to remain limited. Still, a few of the strongest storms just ahead of the dry slot -- and perhaps north of the surge over eastern Montana -- may produce locally damaging winds, and marginal hail. ...Minnesota vicinity... While elevated storms are forecast to be ongoing over portions of the upper Mississippi Valley area at the start of the period, any severe risk appears to be limited, and confined to marginal hail, given the anticipated, elevated nature of the storms. Convection should diminish through the morning. Overnight, as the cold front advances across the northern Plains, redevelopment of storms is expected, possibly evolving into a squall line through latter stages of the period. With this said, storms are not expected to be particularly vigorous for the most part, given that stronger flow aloft is expected to lag the surface frontal location, and thus only modest shear is forecast atop the frontal zone. Still, some hail -- and possibly a strong gust or two -- may occur sporadically with stronger updrafts within the evolving convective band. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Goss.. 09/16/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Mon Sep 16 2019 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN HIGH PLAINS...AND ACROSS THE MINNESOTA VICINITY LATE... ...SUMMARY... A few strong/severe storms are expected across the northern high Plains area Tuesday afternoon/early evening, and may evolve overnight into the Minnesota vicinity. Hail and locally damaging winds will be possible. ...Synopsis... An amplified upper flow field will persist across the U.S. Tuesday/Day 2, as cyclonic flow prevails over the Northeast U.S. and the western States, flanking a central U.S. ridge. Within the broader western U.S. troughing, a vigorous, negatively tilted lead wave is forecast to eject northeastward across the Intermountain region and into the northern high Plains through the period. Ahead of the aforementioned, ejecting short-wave trough, a cold front is progged to advance quickly across the Rockies and into the high Plains through the afternoon, and then eastward across the northern and central Plains overnight. This front -- and the convection associated with it -- will drive the main area of severe potential across north-central portions of the U.S. on Tuesday. ...Northern high Plains... As the surface cold front advances quickly eastward across the northern High Plains region, scattered showers and thunderstorms are expected to develop during the afternoon -- perhaps as far west as the Bighorns, and then spreading quickly across the high Plains. With somewhat limited CAPE expected, and a substantial dry slot expected to surge eastward across Wyoming and the western Dakotas, severe risk appears likely to remain limited. Still, a few of the strongest storms just ahead of the dry slot -- and perhaps north of the surge over eastern Montana -- may produce locally damaging winds, and marginal hail. ...Minnesota vicinity... While elevated storms are forecast to be ongoing over portions of the upper Mississippi Valley area at the start of the period, any severe risk appears to be limited, and confined to marginal hail, given the anticipated, elevated nature of the storms. Convection should diminish through the morning. Overnight, as the cold front advances across the northern Plains, redevelopment of storms is expected, possibly evolving into a squall line through latter stages of the period. With this said, storms are not expected to be particularly vigorous for the most part, given that stronger flow aloft is expected to lag the surface frontal location, and thus only modest shear is forecast atop the frontal zone. Still, some hail -- and possibly a strong gust or two -- may occur sporadically with stronger updrafts within the evolving convective band. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Goss.. 09/16/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1110 AM CDT Mon Sep 16 2019 Valid 161630Z - 171200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe storms are unlikely today and tonight. ...Synopsis... A deep midlevel trough, with associated cool midlevel temperatures and steep lapse rates, will continue to progress inland over the Pacific Coast today and the Great Basin tonight. Isolated to widely scattered thunderstorms will be possible across portions of the Pacific Northwest into the Great Basin as the trough moves eastward. Elsewhere, multiple shortwave troughs will eject northeastward from the southern Rockies into the northern Plains, resulting in the potential for widely scattered thunderstorms from the High Plains today into portions of the Dakotas/Minnesota late tonight. A weak mid/upper-level trough over the northwestern Gulf will produce widespread convection, with some of this activity spreading inland into coastal portions of LA/TX later today and tonight. While a few stronger storms cannot be ruled out across the Interior Northwest/Great Basin into the Intermountain West, near the TX/LA Gulf Coast, and also across the eastern Dakotas into MN late tonight, the potential for severe thunderstorms is expected to generally remain low through the period. ..Dean.. 09/16/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1110 AM CDT Mon Sep 16 2019 Valid 161630Z - 171200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe storms are unlikely today and tonight. ...Synopsis... A deep midlevel trough, with associated cool midlevel temperatures and steep lapse rates, will continue to progress inland over the Pacific Coast today and the Great Basin tonight. Isolated to widely scattered thunderstorms will be possible across portions of the Pacific Northwest into the Great Basin as the trough moves eastward. Elsewhere, multiple shortwave troughs will eject northeastward from the southern Rockies into the northern Plains, resulting in the potential for widely scattered thunderstorms from the High Plains today into portions of the Dakotas/Minnesota late tonight. A weak mid/upper-level trough over the northwestern Gulf will produce widespread convection, with some of this activity spreading inland into coastal portions of LA/TX later today and tonight. While a few stronger storms cannot be ruled out across the Interior Northwest/Great Basin into the Intermountain West, near the TX/LA Gulf Coast, and also across the eastern Dakotas into MN late tonight, the potential for severe thunderstorms is expected to generally remain low through the period. ..Dean.. 09/16/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1110 AM CDT Mon Sep 16 2019 Valid 161630Z - 171200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe storms are unlikely today and tonight. ...Synopsis... A deep midlevel trough, with associated cool midlevel temperatures and steep lapse rates, will continue to progress inland over the Pacific Coast today and the Great Basin tonight. Isolated to widely scattered thunderstorms will be possible across portions of the Pacific Northwest into the Great Basin as the trough moves eastward. Elsewhere, multiple shortwave troughs will eject northeastward from the southern Rockies into the northern Plains, resulting in the potential for widely scattered thunderstorms from the High Plains today into portions of the Dakotas/Minnesota late tonight. A weak mid/upper-level trough over the northwestern Gulf will produce widespread convection, with some of this activity spreading inland into coastal portions of LA/TX later today and tonight. While a few stronger storms cannot be ruled out across the Interior Northwest/Great Basin into the Intermountain West, near the TX/LA Gulf Coast, and also across the eastern Dakotas into MN late tonight, the potential for severe thunderstorms is expected to generally remain low through the period. ..Dean.. 09/16/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1110 AM CDT Mon Sep 16 2019 Valid 161630Z - 171200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe storms are unlikely today and tonight. ...Synopsis... A deep midlevel trough, with associated cool midlevel temperatures and steep lapse rates, will continue to progress inland over the Pacific Coast today and the Great Basin tonight. Isolated to widely scattered thunderstorms will be possible across portions of the Pacific Northwest into the Great Basin as the trough moves eastward. Elsewhere, multiple shortwave troughs will eject northeastward from the southern Rockies into the northern Plains, resulting in the potential for widely scattered thunderstorms from the High Plains today into portions of the Dakotas/Minnesota late tonight. A weak mid/upper-level trough over the northwestern Gulf will produce widespread convection, with some of this activity spreading inland into coastal portions of LA/TX later today and tonight. While a few stronger storms cannot be ruled out across the Interior Northwest/Great Basin into the Intermountain West, near the TX/LA Gulf Coast, and also across the eastern Dakotas into MN late tonight, the potential for severe thunderstorms is expected to generally remain low through the period. ..Dean.. 09/16/2019 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1112 AM CDT Mon Sep 16 2019 Valid 161700Z - 171200Z ...CRITICAL FIRE WEATHER AREA FOR A LARGE PORTION OF THE GREAT BASIN... A minor expansion was made to the elevated area across portions of southeast Idaho and far western Wyoming. A combination of the latest surface mesoanalysis and high resolution RAP/HRRR/HREF guidance suggests dry and breezy conditions will move northeastward into this region for a few hours during the late afternoon and early evening. Otherwise, the previous forecast for critical fire-weather conditions across a large portion of the Great Basin remains on track. Morning guidance appears to be handling the timing of the cold front well, and thus no other changes are needed. See the discussion below for more details. ..Karstens.. 09/16/2019 .PREV DISCUSSION... /ISSUED 0138 AM CDT Mon Sep 16 2019/ ...Synopsis... A strong upper-level trough and attendant mid-level jet will overspread dry portions of the Great Basin on Monday. At the surface, dry and windy conditions are expected ahead of a cold front which will be located from western Oregon southwestward across northwest Nevada and northern California. Wind speeds are expected to range from 30 to 40 mph across east central Nevada and west central Utah with relative humidity in the 10 to 15 percent range. A large area of critical fire weather conditions is expected across most of Nevada and into western Utah. Wind speeds across this region would support extremely critical fire weather conditions, but some moisture increase from the subtropics should keep relative humidity above extremely critical thresholds. Elevated fire weather conditions will surround the critical area and extend northeastward into eastern Idaho and southwest Montana. In this region, winds are expected to be in the 20 to 25 mph range with relative humidity around 15 to 20 percent. ...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 1112 AM CDT Mon Sep 16 2019 Valid 161700Z - 171200Z ...CRITICAL FIRE WEATHER AREA FOR A LARGE PORTION OF THE GREAT BASIN... A minor expansion was made to the elevated area across portions of southeast Idaho and far western Wyoming. A combination of the latest surface mesoanalysis and high resolution RAP/HRRR/HREF guidance suggests dry and breezy conditions will move northeastward into this region for a few hours during the late afternoon and early evening. Otherwise, the previous forecast for critical fire-weather conditions across a large portion of the Great Basin remains on track. Morning guidance appears to be handling the timing of the cold front well, and thus no other changes are needed. See the discussion below for more details. ..Karstens.. 09/16/2019 .PREV DISCUSSION... /ISSUED 0138 AM CDT Mon Sep 16 2019/ ...Synopsis... A strong upper-level trough and attendant mid-level jet will overspread dry portions of the Great Basin on Monday. At the surface, dry and windy conditions are expected ahead of a cold front which will be located from western Oregon southwestward across northwest Nevada and northern California. Wind speeds are expected to range from 30 to 40 mph across east central Nevada and west central Utah with relative humidity in the 10 to 15 percent range. A large area of critical fire weather conditions is expected across most of Nevada and into western Utah. Wind speeds across this region would support extremely critical fire weather conditions, but some moisture increase from the subtropics should keep relative humidity above extremely critical thresholds. Elevated fire weather conditions will surround the critical area and extend northeastward into eastern Idaho and southwest Montana. In this region, winds are expected to be in the 20 to 25 mph range with relative humidity around 15 to 20 percent. ...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 1112 AM CDT Mon Sep 16 2019 Valid 161700Z - 171200Z ...CRITICAL FIRE WEATHER AREA FOR A LARGE PORTION OF THE GREAT BASIN... A minor expansion was made to the elevated area across portions of southeast Idaho and far western Wyoming. A combination of the latest surface mesoanalysis and high resolution RAP/HRRR/HREF guidance suggests dry and breezy conditions will move northeastward into this region for a few hours during the late afternoon and early evening. Otherwise, the previous forecast for critical fire-weather conditions across a large portion of the Great Basin remains on track. Morning guidance appears to be handling the timing of the cold front well, and thus no other changes are needed. See the discussion below for more details. ..Karstens.. 09/16/2019 .PREV DISCUSSION... /ISSUED 0138 AM CDT Mon Sep 16 2019/ ...Synopsis... A strong upper-level trough and attendant mid-level jet will overspread dry portions of the Great Basin on Monday. At the surface, dry and windy conditions are expected ahead of a cold front which will be located from western Oregon southwestward across northwest Nevada and northern California. Wind speeds are expected to range from 30 to 40 mph across east central Nevada and west central Utah with relative humidity in the 10 to 15 percent range. A large area of critical fire weather conditions is expected across most of Nevada and into western Utah. Wind speeds across this region would support extremely critical fire weather conditions, but some moisture increase from the subtropics should keep relative humidity above extremely critical thresholds. Elevated fire weather conditions will surround the critical area and extend northeastward into eastern Idaho and southwest Montana. In this region, winds are expected to be in the 20 to 25 mph range with relative humidity around 15 to 20 percent. ...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 1112 AM CDT Mon Sep 16 2019 Valid 161700Z - 171200Z ...CRITICAL FIRE WEATHER AREA FOR A LARGE PORTION OF THE GREAT BASIN... A minor expansion was made to the elevated area across portions of southeast Idaho and far western Wyoming. A combination of the latest surface mesoanalysis and high resolution RAP/HRRR/HREF guidance suggests dry and breezy conditions will move northeastward into this region for a few hours during the late afternoon and early evening. Otherwise, the previous forecast for critical fire-weather conditions across a large portion of the Great Basin remains on track. Morning guidance appears to be handling the timing of the cold front well, and thus no other changes are needed. See the discussion below for more details. ..Karstens.. 09/16/2019 .PREV DISCUSSION... /ISSUED 0138 AM CDT Mon Sep 16 2019/ ...Synopsis... A strong upper-level trough and attendant mid-level jet will overspread dry portions of the Great Basin on Monday. At the surface, dry and windy conditions are expected ahead of a cold front which will be located from western Oregon southwestward across northwest Nevada and northern California. Wind speeds are expected to range from 30 to 40 mph across east central Nevada and west central Utah with relative humidity in the 10 to 15 percent range. A large area of critical fire weather conditions is expected across most of Nevada and into western Utah. Wind speeds across this region would support extremely critical fire weather conditions, but some moisture increase from the subtropics should keep relative humidity above extremely critical thresholds. Elevated fire weather conditions will surround the critical area and extend northeastward into eastern Idaho and southwest Montana. In this region, winds are expected to be in the 20 to 25 mph range with relative humidity around 15 to 20 percent. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Mon Sep 16 2019 Valid 161300Z - 171200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe storms are unlikely today and tonight. ...Synopsis... A deep midlevel trough, with associated cool midlevel temperatures and steep lapse rates, will continue to progress inland over the Pacific Coast today and the Great Basin tonight. A few low-topped thunderstorms will be possible the first part of the day along the cold front in northeast CA, while occasional storms will spread inland across OR to northwest NV by this evening. Farther south and east, the cold front will cross NV this evening and reach UT tonight. The monsoonal moisture plume will likely remain east of the front and associated ascent, which casts substantial doubt on the potential for thunderstorms along the front tonight. In response to the Pacific Coast trough, a weakening subtropical shortwave trough over NM/CO will eject northeastward toward the eastern Dakotas/MN and could support some elevated convection near the end of the forecast period. Scattered thunderstorms are likely through tonight near the northwest Gulf coast with a weak tropical disturbance. The convection should spread inland this afternoon with outflows, and then consolidate tonight near the middle and upper TX coast. ..Thompson/Gleason.. 09/16/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Mon Sep 16 2019 Valid 161300Z - 171200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe storms are unlikely today and tonight. ...Synopsis... A deep midlevel trough, with associated cool midlevel temperatures and steep lapse rates, will continue to progress inland over the Pacific Coast today and the Great Basin tonight. A few low-topped thunderstorms will be possible the first part of the day along the cold front in northeast CA, while occasional storms will spread inland across OR to northwest NV by this evening. Farther south and east, the cold front will cross NV this evening and reach UT tonight. The monsoonal moisture plume will likely remain east of the front and associated ascent, which casts substantial doubt on the potential for thunderstorms along the front tonight. In response to the Pacific Coast trough, a weakening subtropical shortwave trough over NM/CO will eject northeastward toward the eastern Dakotas/MN and could support some elevated convection near the end of the forecast period. Scattered thunderstorms are likely through tonight near the northwest Gulf coast with a weak tropical disturbance. The convection should spread inland this afternoon with outflows, and then consolidate tonight near the middle and upper TX coast. ..Thompson/Gleason.. 09/16/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Mon Sep 16 2019 Valid 161300Z - 171200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe storms are unlikely today and tonight. ...Synopsis... A deep midlevel trough, with associated cool midlevel temperatures and steep lapse rates, will continue to progress inland over the Pacific Coast today and the Great Basin tonight. A few low-topped thunderstorms will be possible the first part of the day along the cold front in northeast CA, while occasional storms will spread inland across OR to northwest NV by this evening. Farther south and east, the cold front will cross NV this evening and reach UT tonight. The monsoonal moisture plume will likely remain east of the front and associated ascent, which casts substantial doubt on the potential for thunderstorms along the front tonight. In response to the Pacific Coast trough, a weakening subtropical shortwave trough over NM/CO will eject northeastward toward the eastern Dakotas/MN and could support some elevated convection near the end of the forecast period. Scattered thunderstorms are likely through tonight near the northwest Gulf coast with a weak tropical disturbance. The convection should spread inland this afternoon with outflows, and then consolidate tonight near the middle and upper TX coast. ..Thompson/Gleason.. 09/16/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Mon Sep 16 2019 Valid 161300Z - 171200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe storms are unlikely today and tonight. ...Synopsis... A deep midlevel trough, with associated cool midlevel temperatures and steep lapse rates, will continue to progress inland over the Pacific Coast today and the Great Basin tonight. A few low-topped thunderstorms will be possible the first part of the day along the cold front in northeast CA, while occasional storms will spread inland across OR to northwest NV by this evening. Farther south and east, the cold front will cross NV this evening and reach UT tonight. The monsoonal moisture plume will likely remain east of the front and associated ascent, which casts substantial doubt on the potential for thunderstorms along the front tonight. In response to the Pacific Coast trough, a weakening subtropical shortwave trough over NM/CO will eject northeastward toward the eastern Dakotas/MN and could support some elevated convection near the end of the forecast period. Scattered thunderstorms are likely through tonight near the northwest Gulf coast with a weak tropical disturbance. The convection should spread inland this afternoon with outflows, and then consolidate tonight near the middle and upper TX coast. ..Thompson/Gleason.. 09/16/2019 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CDT Mon Sep 16 2019 Valid 191200Z - 241200Z ...DISCUSSION... Amplified mid-level troughing, within a southern branch of split westerlies, appears likely to accelerate northeastward out of the Intermountain West late this work week. The latest medium-range guidance suggests that there may be phasing with a northern branch perturbation, with associated forcing for ascent contributing to fairly significant surface cyclogenesis across and north of the central Canadian/U.S. border area by early next weekend. Friday (Day 5), it appears that the warm sector of the deepening cyclone may become characterized by moderately large CAPE on the order of 2000+ J/kg, in the presence of strengthening lower/mid tropospheric wind fields (including south to southwesterly at 40-50+ kt in the 850-500 mb layer), across parts of the eastern Dakotas into Minnesota. This may provide the most favorable support for organized severe thunderstorm development during the period, with the evolution of a few supercells and a squall line possible late Friday afternoon and evening. The westerlies may then transition to less amplified and split across the U.S. next weekend into early next week, downstream of broad mid-level ridging developing eastward across the mid-latitude eastern Pacific, toward the Pacific coast. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CDT Mon Sep 16 2019 Valid 191200Z - 241200Z ...DISCUSSION... Amplified mid-level troughing, within a southern branch of split westerlies, appears likely to accelerate northeastward out of the Intermountain West late this work week. The latest medium-range guidance suggests that there may be phasing with a northern branch perturbation, with associated forcing for ascent contributing to fairly significant surface cyclogenesis across and north of the central Canadian/U.S. border area by early next weekend. Friday (Day 5), it appears that the warm sector of the deepening cyclone may become characterized by moderately large CAPE on the order of 2000+ J/kg, in the presence of strengthening lower/mid tropospheric wind fields (including south to southwesterly at 40-50+ kt in the 850-500 mb layer), across parts of the eastern Dakotas into Minnesota. This may provide the most favorable support for organized severe thunderstorm development during the period, with the evolution of a few supercells and a squall line possible late Friday afternoon and evening. The westerlies may then transition to less amplified and split across the U.S. next weekend into early next week, downstream of broad mid-level ridging developing eastward across the mid-latitude eastern Pacific, toward the Pacific coast. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CDT Mon Sep 16 2019 Valid 191200Z - 241200Z ...DISCUSSION... Amplified mid-level troughing, within a southern branch of split westerlies, appears likely to accelerate northeastward out of the Intermountain West late this work week. The latest medium-range guidance suggests that there may be phasing with a northern branch perturbation, with associated forcing for ascent contributing to fairly significant surface cyclogenesis across and north of the central Canadian/U.S. border area by early next weekend. Friday (Day 5), it appears that the warm sector of the deepening cyclone may become characterized by moderately large CAPE on the order of 2000+ J/kg, in the presence of strengthening lower/mid tropospheric wind fields (including south to southwesterly at 40-50+ kt in the 850-500 mb layer), across parts of the eastern Dakotas into Minnesota. This may provide the most favorable support for organized severe thunderstorm development during the period, with the evolution of a few supercells and a squall line possible late Friday afternoon and evening. The westerlies may then transition to less amplified and split across the U.S. next weekend into early next week, downstream of broad mid-level ridging developing eastward across the mid-latitude eastern Pacific, toward the Pacific coast. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CDT Mon Sep 16 2019 Valid 191200Z - 241200Z ...DISCUSSION... Amplified mid-level troughing, within a southern branch of split westerlies, appears likely to accelerate northeastward out of the Intermountain West late this work week. The latest medium-range guidance suggests that there may be phasing with a northern branch perturbation, with associated forcing for ascent contributing to fairly significant surface cyclogenesis across and north of the central Canadian/U.S. border area by early next weekend. Friday (Day 5), it appears that the warm sector of the deepening cyclone may become characterized by moderately large CAPE on the order of 2000+ J/kg, in the presence of strengthening lower/mid tropospheric wind fields (including south to southwesterly at 40-50+ kt in the 850-500 mb layer), across parts of the eastern Dakotas into Minnesota. This may provide the most favorable support for organized severe thunderstorm development during the period, with the evolution of a few supercells and a squall line possible late Friday afternoon and evening. The westerlies may then transition to less amplified and split across the U.S. next weekend into early next week, downstream of broad mid-level ridging developing eastward across the mid-latitude eastern Pacific, toward the Pacific coast. Read more