Severe Storms

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1140 PM CDT Mon Oct 30 2023 Valid 011200Z - 021200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S., Wednesday through Wednesday night. ...Discussion... Models indicate that the sheared remnants of an initially vigorous short wave impulse of Arctic origins will be in the process of accelerating east-northeast of the lower Great Lakes/upper Ohio Valley vicinity by 12Z Wednesday, before progressing across the northern Atlantic coast late Wednesday afternoon and evening. In the wake of this perturbation, broadly confluent, cyclonic mid-level flow is forecast to linger across much of the nation east of the Rockies. Beneath this regime, cold surface ridging likely will build east-northeastward across much of the Northeast, while being maintained along an axis across the northwestern Gulf coast through lower Mississippi Valley and southern Appalachians vicinity. A notable short wave trough may approach the British Columbia and Pacific Northwest coast by late Wednesday night, further suppressing large-scale mid-level ridging lingering across the North American Pacific coast vicinity. This feature may be preceded by a fairly extensive precipitation shield with embedded convection, along an associated occluding surface cyclone and trailing frontal zone. However, while forecast soundings inland of coastal areas depict layers of weak elevated instability, relatively warm layers/weak lapse rates farther aloft seem likely to minimize the potential for more than isolated/sparse lightning strikes. The forecast mid-level cold core appears rather modest, and is likely to remain offshore through this period. ..Kerr.. 10/31/2023 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1140 PM CDT Mon Oct 30 2023 Valid 011200Z - 021200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S., Wednesday through Wednesday night. ...Discussion... Models indicate that the sheared remnants of an initially vigorous short wave impulse of Arctic origins will be in the process of accelerating east-northeast of the lower Great Lakes/upper Ohio Valley vicinity by 12Z Wednesday, before progressing across the northern Atlantic coast late Wednesday afternoon and evening. In the wake of this perturbation, broadly confluent, cyclonic mid-level flow is forecast to linger across much of the nation east of the Rockies. Beneath this regime, cold surface ridging likely will build east-northeastward across much of the Northeast, while being maintained along an axis across the northwestern Gulf coast through lower Mississippi Valley and southern Appalachians vicinity. A notable short wave trough may approach the British Columbia and Pacific Northwest coast by late Wednesday night, further suppressing large-scale mid-level ridging lingering across the North American Pacific coast vicinity. This feature may be preceded by a fairly extensive precipitation shield with embedded convection, along an associated occluding surface cyclone and trailing frontal zone. However, while forecast soundings inland of coastal areas depict layers of weak elevated instability, relatively warm layers/weak lapse rates farther aloft seem likely to minimize the potential for more than isolated/sparse lightning strikes. The forecast mid-level cold core appears rather modest, and is likely to remain offshore through this period. ..Kerr.. 10/31/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1155 PM CDT Mon Oct 30 2023 Valid 311200Z - 011200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Little thunderstorm activity is expected across the Lower 48 today. ...Synopsis... A large-scale upper trough will sweep eastward across the upper Great Lakes and into the middle and lower MS Valley during the day, reaching into the northeastern states and to the Appalachians by 12Z Wed. Strong northwest flow aloft will exist behind this trough, from the Plains into the Southeast, resulting in a stable pattern for thunderstorms. At the surface, high pressure will be centered over the Plains, with strong northerly winds across the Gulf of Mexico and off the East Coast. Given this flow regime, any appreciable low-level moisture will be largely offshore. Weak low-level instability may develop beneath the upper low where lapse rates will be steep, and with the aid of moist winds across the Great Lakes. The most likely area for a few lightning flashes appears to be near Lake MI as a reinforcing cold front enhances low-level convergence. Inversion heights will rise during the evening farther east toward Lake Erie as well, and isolated lightning flashes cannot be ruled out with any lake-enhanced, convective showers. ..Jewell/Squitieri.. 10/31/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1155 PM CDT Mon Oct 30 2023 Valid 311200Z - 011200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Little thunderstorm activity is expected across the Lower 48 today. ...Synopsis... A large-scale upper trough will sweep eastward across the upper Great Lakes and into the middle and lower MS Valley during the day, reaching into the northeastern states and to the Appalachians by 12Z Wed. Strong northwest flow aloft will exist behind this trough, from the Plains into the Southeast, resulting in a stable pattern for thunderstorms. At the surface, high pressure will be centered over the Plains, with strong northerly winds across the Gulf of Mexico and off the East Coast. Given this flow regime, any appreciable low-level moisture will be largely offshore. Weak low-level instability may develop beneath the upper low where lapse rates will be steep, and with the aid of moist winds across the Great Lakes. The most likely area for a few lightning flashes appears to be near Lake MI as a reinforcing cold front enhances low-level convergence. Inversion heights will rise during the evening farther east toward Lake Erie as well, and isolated lightning flashes cannot be ruled out with any lake-enhanced, convective showers. ..Jewell/Squitieri.. 10/31/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1155 PM CDT Mon Oct 30 2023 Valid 311200Z - 011200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Little thunderstorm activity is expected across the Lower 48 today. ...Synopsis... A large-scale upper trough will sweep eastward across the upper Great Lakes and into the middle and lower MS Valley during the day, reaching into the northeastern states and to the Appalachians by 12Z Wed. Strong northwest flow aloft will exist behind this trough, from the Plains into the Southeast, resulting in a stable pattern for thunderstorms. At the surface, high pressure will be centered over the Plains, with strong northerly winds across the Gulf of Mexico and off the East Coast. Given this flow regime, any appreciable low-level moisture will be largely offshore. Weak low-level instability may develop beneath the upper low where lapse rates will be steep, and with the aid of moist winds across the Great Lakes. The most likely area for a few lightning flashes appears to be near Lake MI as a reinforcing cold front enhances low-level convergence. Inversion heights will rise during the evening farther east toward Lake Erie as well, and isolated lightning flashes cannot be ruled out with any lake-enhanced, convective showers. ..Jewell/Squitieri.. 10/31/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1155 PM CDT Mon Oct 30 2023 Valid 311200Z - 011200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Little thunderstorm activity is expected across the Lower 48 today. ...Synopsis... A large-scale upper trough will sweep eastward across the upper Great Lakes and into the middle and lower MS Valley during the day, reaching into the northeastern states and to the Appalachians by 12Z Wed. Strong northwest flow aloft will exist behind this trough, from the Plains into the Southeast, resulting in a stable pattern for thunderstorms. At the surface, high pressure will be centered over the Plains, with strong northerly winds across the Gulf of Mexico and off the East Coast. Given this flow regime, any appreciable low-level moisture will be largely offshore. Weak low-level instability may develop beneath the upper low where lapse rates will be steep, and with the aid of moist winds across the Great Lakes. The most likely area for a few lightning flashes appears to be near Lake MI as a reinforcing cold front enhances low-level convergence. Inversion heights will rise during the evening farther east toward Lake Erie as well, and isolated lightning flashes cannot be ruled out with any lake-enhanced, convective showers. ..Jewell/Squitieri.. 10/31/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1155 PM CDT Mon Oct 30 2023 Valid 311200Z - 011200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Little thunderstorm activity is expected across the Lower 48 today. ...Synopsis... A large-scale upper trough will sweep eastward across the upper Great Lakes and into the middle and lower MS Valley during the day, reaching into the northeastern states and to the Appalachians by 12Z Wed. Strong northwest flow aloft will exist behind this trough, from the Plains into the Southeast, resulting in a stable pattern for thunderstorms. At the surface, high pressure will be centered over the Plains, with strong northerly winds across the Gulf of Mexico and off the East Coast. Given this flow regime, any appreciable low-level moisture will be largely offshore. Weak low-level instability may develop beneath the upper low where lapse rates will be steep, and with the aid of moist winds across the Great Lakes. The most likely area for a few lightning flashes appears to be near Lake MI as a reinforcing cold front enhances low-level convergence. Inversion heights will rise during the evening farther east toward Lake Erie as well, and isolated lightning flashes cannot be ruled out with any lake-enhanced, convective showers. ..Jewell/Squitieri.. 10/31/2023 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0732 PM CDT Mon Oct 30 2023 Valid 310100Z - 311200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected through Tuesday morning. A large area of high pressure will continue to build south across the central and eastern CONUS, with offshore winds increasing across the Gulf of Mexico and coastal Southeast. As such, little to no instability will be present to interact with the large upper trough over the Midwest and Great Lakes. Shallow convective showers will remain possible in the vicinity of southern Lake Superior to Lake Huron, aided by relatively warm water. However, forecast soundings indicate little potential for lightning. ..Jewell.. 10/31/2023 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0732 PM CDT Mon Oct 30 2023 Valid 310100Z - 311200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected through Tuesday morning. A large area of high pressure will continue to build south across the central and eastern CONUS, with offshore winds increasing across the Gulf of Mexico and coastal Southeast. As such, little to no instability will be present to interact with the large upper trough over the Midwest and Great Lakes. Shallow convective showers will remain possible in the vicinity of southern Lake Superior to Lake Huron, aided by relatively warm water. However, forecast soundings indicate little potential for lightning. ..Jewell.. 10/31/2023 Read more

No Mesoscale Discussions are in effect as of Mon Oct 30 02:53:02 UTC 2023.

No watches are valid as of Mon Oct 30 02:53:02 UTC 2023.

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0728 PM CDT Sun Oct 29 2023 Valid 300100Z - 301200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Minimal thunderstorm activity is expected through tonight. ...Synopsis... A large, positive-tile upper trough will continue to push eastward across the upper MS Valley and Great Lakes, trailing southwestward into the central Plains. At the surface, a sprawling area of high pressure will support cool air moving southward across the remainder of southern TX this evening and across the lower MS, OH and TN Valley through Monday morning. Weak elevated instability continues to support embedded thunder within patches of precipitation, mainly over northwest into west-central TX in closer proximity to better moisture and with a few hundred J/kg MUCAPE. With time, the deepening cool air should shunt thunderstorm potential farther south, from central TX toward the middle Rio Grande Valley. Lack of appreciable instability and weak lapse rates aloft will preclude any severe hail risk. ..Jewell.. 10/30/2023 Read more

No Mesoscale Discussions are in effect as of Sun Oct 29 03:05:02 UTC 2023.

No watches are valid as of Sun Oct 29 03:05:02 UTC 2023.

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 PM CDT Sat Oct 28 2023 Valid 290100Z - 291200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER FAR SOUTHWEST TEXAS AND EXTREME SOUTHEAST NEW MEXICO... ...SUMMARY... A few strong to marginally severe storm remain possible this evening and into the early morning hours over a small part of west Texas and extreme southeastern New Mexico. ...Southwest TX... A cold front currently extends from central TX into southeast NM, with a gradual southward motion. The 00Z MAF sounding shows a capping inversion with around 1100 J/kg MLCAPE, and moderate mid to high level flow. Ongoing small cells exist to the southwest, but remain quite disorganized. Sporadic cells may persist in the relatively warmer air, prior to frontal passage. Despite the likelihood of elevated parcels north of the front, sufficient instability may still support a marginal hail threat as the deepening post-frontal air mass aids cap removal for elevated parcels. Moderate southwest flow aloft with the positive-tilt trough may enhance deep-layer shear somewhat tonight, possibly supporting isolated cells producing marginal hail. ..Jewell.. 10/29/2023 Read more

No watches are valid as of Sat Oct 28 03:11:01 UTC 2023.

No Mesoscale Discussions are in effect as of Sat Oct 28 03:11:01 UTC 2023.

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 PM CDT Fri Oct 27 2023 Valid 280100Z - 281200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the contiguous United States through tonight. ...Synopsis... A mean mid-level trough will reside over the West and an anticyclone will remain centered over FL. Water-vapor imagery this evening shows a weak disturbance moving east-northeast across the IA/WI vicinity. This mid to upper-level feature will continue into MI tonight and into southeast Canada by early Saturday morning. In the low levels, a cold front over Lower MI extends south-southwest into eastern IL and into central TX. The northern portion of the front will continue sweeping east across the central Great Lakes and parts of the OH Valley. A few thunderstorms will remain possible near the front over the Midwest. Weak buoyancy from the Mid South northward into the Great Lakes (i.e., reference 00z area raobs) will likely limit both storm coverage/intensity through the early morning. ..Smith.. 10/28/2023 Read more

No watches are valid as of Fri Oct 27 03:24:02 UTC 2023.

MD 2264 CONCERNING HEAVY SNOW FOR PORTIONS OF EASTERN NORTH DAKOTA INTO EXTREME NORTHWESTERN MINNESOTA
Mesoscale Discussion 2264 NWS Storm Prediction Center Norman OK 1021 PM CDT Thu Oct 26 2023 Areas affected...portions of eastern North Dakota into extreme northwestern Minnesota Concerning...Heavy snow Valid 270321Z - 270915Z SUMMARY...Occasional instances of heavy snow, including 1-1.5 inch/hour snowfall rates, are possible tonight across portions of eastern North Dakota into extreme northwestern Minnesota. DISCUSSION...A pronounced mid-level trough, located over western SD, is poised to overspread the eastern Dakotas over the next few hours, increasing deep-layer ascent and supporting higher precipitation rates across eastern portions of the Northern Plains tonight. At the same time, modest northeasterly 850 mb warm-air advection (to the northwest of a surface low) over the Upper MS Valley will continue to increase low-level lift and moisture ahead of an ongoing snow band across central ND and northern SD. Given near saturation at 700 mb (which is also in proximity to the dendritic growth zone), increased deep-layer ascent tonight will promote moderate to heavy snow. Some of the latest CAM guidance (i.e. deterministic HRRR and HREF- ensemble probabilities) suggests that the best chance for 1-1.5 inch/hour snowfall rates will be across northeast ND into extreme northwest MN in the 05-09Z (Midnight - 4 AM CDT) time frame. ..Squitieri.. 10/27/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGF...BIS... LAT...LON 45980148 47280106 48260061 48640015 48939928 49049847 49039807 49049703 48759676 48229670 47649706 46719865 46239972 45980045 45980148 Read more