Severe Storms

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0639 AM CST Wed Jan 17 2024 Valid 171300Z - 181200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected in the conterminous U.S. through tonight. ...Synopsis/Discussion... In mid/upper levels, broadly cyclonic mean flow will be maintained over most of the CONUS, downstream from a synoptic ridge that will move over the Pacific Coast around the end of the period. A cyclone that moved ashore during the prior overnight period has devolved to an open shortwave trough over OR. This feature should deamplify gradually as it rapidly crosses the northern Great Basin to central Rockies today, reaching MO and OK by 12Z tomorrow. Though a flash or two cannot be ruled out as the associated midlevel cooling/ moisture cross the Intermountain West today, lightning potential appears too isolated, brief and unfocused to warrant an outlook area. Otherwise, troughing over the East will deamplify somewhat today as a strong shortwave exits the East Coast. A related/preceding surface cold front -- initially analyzed from the northern Bahamas across the eastern/southern Straits of FL -- will decelerate, weaken, and remain south of FL through the period. Lightning potential over land appears minimal at best, and too low for a 10% areal outline. Elsewhere, the air mass will be too dry and/or stable for thunder over the CONUS. ..Edwards/Dean.. 01/17/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0332 AM CST Wed Jan 17 2024 Valid 201200Z - 251200Z ...DISCUSSION... An upper trough over the eastern U.S. will quickly move east over the Atlantic on Day 4/Sat. Meanwhile, an upper ridge over the Rockies will spread east into the Plains, while another upper trough develops along the Pacific coast. This pattern will progress eastward through the period, with upper ridge becoming established over the eastern half of the CONUS Days 5-8/Sun-Wed. The Pacific coast upper trough will slowly develop east, spreading into the Plains by Day 8/Wed. Dry and stable conditions, courtesy of strong surface high pressure and a prior cold frontal intrusion deep into the Gulf of Mexico, will limit thunderstorm potential through at least Day 5 or 6/Sun or Mon. However, as the western upper trough approaches the Rockies and Plains, lee surface troughing will support southerly return flow across the western Gulf and Plains. Thunderstorm potential may return to parts of TX and the western Gulf coast vicinity toward the end of the period. While some severe potential could accompany this moisture return ahead of the upper trough, uncertainty in quality of low-level moisture, and timing of the eastward-advancing upper trough, remains too high to include probabilities at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0332 AM CST Wed Jan 17 2024 Valid 201200Z - 251200Z ...DISCUSSION... An upper trough over the eastern U.S. will quickly move east over the Atlantic on Day 4/Sat. Meanwhile, an upper ridge over the Rockies will spread east into the Plains, while another upper trough develops along the Pacific coast. This pattern will progress eastward through the period, with upper ridge becoming established over the eastern half of the CONUS Days 5-8/Sun-Wed. The Pacific coast upper trough will slowly develop east, spreading into the Plains by Day 8/Wed. Dry and stable conditions, courtesy of strong surface high pressure and a prior cold frontal intrusion deep into the Gulf of Mexico, will limit thunderstorm potential through at least Day 5 or 6/Sun or Mon. However, as the western upper trough approaches the Rockies and Plains, lee surface troughing will support southerly return flow across the western Gulf and Plains. Thunderstorm potential may return to parts of TX and the western Gulf coast vicinity toward the end of the period. While some severe potential could accompany this moisture return ahead of the upper trough, uncertainty in quality of low-level moisture, and timing of the eastward-advancing upper trough, remains too high to include probabilities at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0332 AM CST Wed Jan 17 2024 Valid 201200Z - 251200Z ...DISCUSSION... An upper trough over the eastern U.S. will quickly move east over the Atlantic on Day 4/Sat. Meanwhile, an upper ridge over the Rockies will spread east into the Plains, while another upper trough develops along the Pacific coast. This pattern will progress eastward through the period, with upper ridge becoming established over the eastern half of the CONUS Days 5-8/Sun-Wed. The Pacific coast upper trough will slowly develop east, spreading into the Plains by Day 8/Wed. Dry and stable conditions, courtesy of strong surface high pressure and a prior cold frontal intrusion deep into the Gulf of Mexico, will limit thunderstorm potential through at least Day 5 or 6/Sun or Mon. However, as the western upper trough approaches the Rockies and Plains, lee surface troughing will support southerly return flow across the western Gulf and Plains. Thunderstorm potential may return to parts of TX and the western Gulf coast vicinity toward the end of the period. While some severe potential could accompany this moisture return ahead of the upper trough, uncertainty in quality of low-level moisture, and timing of the eastward-advancing upper trough, remains too high to include probabilities at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0332 AM CST Wed Jan 17 2024 Valid 201200Z - 251200Z ...DISCUSSION... An upper trough over the eastern U.S. will quickly move east over the Atlantic on Day 4/Sat. Meanwhile, an upper ridge over the Rockies will spread east into the Plains, while another upper trough develops along the Pacific coast. This pattern will progress eastward through the period, with upper ridge becoming established over the eastern half of the CONUS Days 5-8/Sun-Wed. The Pacific coast upper trough will slowly develop east, spreading into the Plains by Day 8/Wed. Dry and stable conditions, courtesy of strong surface high pressure and a prior cold frontal intrusion deep into the Gulf of Mexico, will limit thunderstorm potential through at least Day 5 or 6/Sun or Mon. However, as the western upper trough approaches the Rockies and Plains, lee surface troughing will support southerly return flow across the western Gulf and Plains. Thunderstorm potential may return to parts of TX and the western Gulf coast vicinity toward the end of the period. While some severe potential could accompany this moisture return ahead of the upper trough, uncertainty in quality of low-level moisture, and timing of the eastward-advancing upper trough, remains too high to include probabilities at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0332 AM CST Wed Jan 17 2024 Valid 201200Z - 251200Z ...DISCUSSION... An upper trough over the eastern U.S. will quickly move east over the Atlantic on Day 4/Sat. Meanwhile, an upper ridge over the Rockies will spread east into the Plains, while another upper trough develops along the Pacific coast. This pattern will progress eastward through the period, with upper ridge becoming established over the eastern half of the CONUS Days 5-8/Sun-Wed. The Pacific coast upper trough will slowly develop east, spreading into the Plains by Day 8/Wed. Dry and stable conditions, courtesy of strong surface high pressure and a prior cold frontal intrusion deep into the Gulf of Mexico, will limit thunderstorm potential through at least Day 5 or 6/Sun or Mon. However, as the western upper trough approaches the Rockies and Plains, lee surface troughing will support southerly return flow across the western Gulf and Plains. Thunderstorm potential may return to parts of TX and the western Gulf coast vicinity toward the end of the period. While some severe potential could accompany this moisture return ahead of the upper trough, uncertainty in quality of low-level moisture, and timing of the eastward-advancing upper trough, remains too high to include probabilities at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0332 AM CST Wed Jan 17 2024 Valid 201200Z - 251200Z ...DISCUSSION... An upper trough over the eastern U.S. will quickly move east over the Atlantic on Day 4/Sat. Meanwhile, an upper ridge over the Rockies will spread east into the Plains, while another upper trough develops along the Pacific coast. This pattern will progress eastward through the period, with upper ridge becoming established over the eastern half of the CONUS Days 5-8/Sun-Wed. The Pacific coast upper trough will slowly develop east, spreading into the Plains by Day 8/Wed. Dry and stable conditions, courtesy of strong surface high pressure and a prior cold frontal intrusion deep into the Gulf of Mexico, will limit thunderstorm potential through at least Day 5 or 6/Sun or Mon. However, as the western upper trough approaches the Rockies and Plains, lee surface troughing will support southerly return flow across the western Gulf and Plains. Thunderstorm potential may return to parts of TX and the western Gulf coast vicinity toward the end of the period. While some severe potential could accompany this moisture return ahead of the upper trough, uncertainty in quality of low-level moisture, and timing of the eastward-advancing upper trough, remains too high to include probabilities at this time. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0204 AM CST Wed Jan 17 2024 Valid 191200Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Friday. ...Synopsis... Surface low pressure will be located over NC Friday morning. A trailing cold front will extend southwest from the low into southern GA and northern Gulf of Mexico. The front will rapidly move offshore the Southeast coast and across the FL Peninsula. While modest boundary-layer moisture will reside across the FL Peninsula, poor lapse rates and weak instability will preclude thunderstorm activity before the front moves offshore by mid afternoon. In the wake of the front, strong surface high pressure will develop over the Plains. A dry and stable airmass behind the front will limit thunderstorm potential. ..Leitman.. 01/17/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0204 AM CST Wed Jan 17 2024 Valid 191200Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Friday. ...Synopsis... Surface low pressure will be located over NC Friday morning. A trailing cold front will extend southwest from the low into southern GA and northern Gulf of Mexico. The front will rapidly move offshore the Southeast coast and across the FL Peninsula. While modest boundary-layer moisture will reside across the FL Peninsula, poor lapse rates and weak instability will preclude thunderstorm activity before the front moves offshore by mid afternoon. In the wake of the front, strong surface high pressure will develop over the Plains. A dry and stable airmass behind the front will limit thunderstorm potential. ..Leitman.. 01/17/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0204 AM CST Wed Jan 17 2024 Valid 191200Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Friday. ...Synopsis... Surface low pressure will be located over NC Friday morning. A trailing cold front will extend southwest from the low into southern GA and northern Gulf of Mexico. The front will rapidly move offshore the Southeast coast and across the FL Peninsula. While modest boundary-layer moisture will reside across the FL Peninsula, poor lapse rates and weak instability will preclude thunderstorm activity before the front moves offshore by mid afternoon. In the wake of the front, strong surface high pressure will develop over the Plains. A dry and stable airmass behind the front will limit thunderstorm potential. ..Leitman.. 01/17/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0204 AM CST Wed Jan 17 2024 Valid 191200Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Friday. ...Synopsis... Surface low pressure will be located over NC Friday morning. A trailing cold front will extend southwest from the low into southern GA and northern Gulf of Mexico. The front will rapidly move offshore the Southeast coast and across the FL Peninsula. While modest boundary-layer moisture will reside across the FL Peninsula, poor lapse rates and weak instability will preclude thunderstorm activity before the front moves offshore by mid afternoon. In the wake of the front, strong surface high pressure will develop over the Plains. A dry and stable airmass behind the front will limit thunderstorm potential. ..Leitman.. 01/17/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0204 AM CST Wed Jan 17 2024 Valid 191200Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Friday. ...Synopsis... Surface low pressure will be located over NC Friday morning. A trailing cold front will extend southwest from the low into southern GA and northern Gulf of Mexico. The front will rapidly move offshore the Southeast coast and across the FL Peninsula. While modest boundary-layer moisture will reside across the FL Peninsula, poor lapse rates and weak instability will preclude thunderstorm activity before the front moves offshore by mid afternoon. In the wake of the front, strong surface high pressure will develop over the Plains. A dry and stable airmass behind the front will limit thunderstorm potential. ..Leitman.. 01/17/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0204 AM CST Wed Jan 17 2024 Valid 191200Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Friday. ...Synopsis... Surface low pressure will be located over NC Friday morning. A trailing cold front will extend southwest from the low into southern GA and northern Gulf of Mexico. The front will rapidly move offshore the Southeast coast and across the FL Peninsula. While modest boundary-layer moisture will reside across the FL Peninsula, poor lapse rates and weak instability will preclude thunderstorm activity before the front moves offshore by mid afternoon. In the wake of the front, strong surface high pressure will develop over the Plains. A dry and stable airmass behind the front will limit thunderstorm potential. ..Leitman.. 01/17/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1224 AM CST Wed Jan 17 2024 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Thursday. ...Synopsis... A shortwave upper trough embedded within a broader trough east of the Rockies will pivot east from the southern Plains to the Carolinas on Thursday. At the surface, a weak low will move in tandem with the shortwave impulse across the Gulf coast states vicinity. A trailing cold front will sweep southeast across the Southeast during the period, extending from southern GA into the northern Gulf of Mexico by Friday morning. Southerly low-level flow ahead of the front will allow upper 50s to near 60 F dewpoints to impinge on the central Gulf coast, with somewhat higher dewpoints expected across central/southern FL. While boundary-layer moisture will be greater across the FL Peninsula, poor lapse rates and relatively warm midlevel temperatures will result in capping and limit destabilization. A few lightning flashes may occur over parts of the Peninsula, but severe storms are not expected. ..Leitman.. 01/17/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1224 AM CST Wed Jan 17 2024 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Thursday. ...Synopsis... A shortwave upper trough embedded within a broader trough east of the Rockies will pivot east from the southern Plains to the Carolinas on Thursday. At the surface, a weak low will move in tandem with the shortwave impulse across the Gulf coast states vicinity. A trailing cold front will sweep southeast across the Southeast during the period, extending from southern GA into the northern Gulf of Mexico by Friday morning. Southerly low-level flow ahead of the front will allow upper 50s to near 60 F dewpoints to impinge on the central Gulf coast, with somewhat higher dewpoints expected across central/southern FL. While boundary-layer moisture will be greater across the FL Peninsula, poor lapse rates and relatively warm midlevel temperatures will result in capping and limit destabilization. A few lightning flashes may occur over parts of the Peninsula, but severe storms are not expected. ..Leitman.. 01/17/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1224 AM CST Wed Jan 17 2024 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Thursday. ...Synopsis... A shortwave upper trough embedded within a broader trough east of the Rockies will pivot east from the southern Plains to the Carolinas on Thursday. At the surface, a weak low will move in tandem with the shortwave impulse across the Gulf coast states vicinity. A trailing cold front will sweep southeast across the Southeast during the period, extending from southern GA into the northern Gulf of Mexico by Friday morning. Southerly low-level flow ahead of the front will allow upper 50s to near 60 F dewpoints to impinge on the central Gulf coast, with somewhat higher dewpoints expected across central/southern FL. While boundary-layer moisture will be greater across the FL Peninsula, poor lapse rates and relatively warm midlevel temperatures will result in capping and limit destabilization. A few lightning flashes may occur over parts of the Peninsula, but severe storms are not expected. ..Leitman.. 01/17/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1224 AM CST Wed Jan 17 2024 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Thursday. ...Synopsis... A shortwave upper trough embedded within a broader trough east of the Rockies will pivot east from the southern Plains to the Carolinas on Thursday. At the surface, a weak low will move in tandem with the shortwave impulse across the Gulf coast states vicinity. A trailing cold front will sweep southeast across the Southeast during the period, extending from southern GA into the northern Gulf of Mexico by Friday morning. Southerly low-level flow ahead of the front will allow upper 50s to near 60 F dewpoints to impinge on the central Gulf coast, with somewhat higher dewpoints expected across central/southern FL. While boundary-layer moisture will be greater across the FL Peninsula, poor lapse rates and relatively warm midlevel temperatures will result in capping and limit destabilization. A few lightning flashes may occur over parts of the Peninsula, but severe storms are not expected. ..Leitman.. 01/17/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1224 AM CST Wed Jan 17 2024 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Thursday. ...Synopsis... A shortwave upper trough embedded within a broader trough east of the Rockies will pivot east from the southern Plains to the Carolinas on Thursday. At the surface, a weak low will move in tandem with the shortwave impulse across the Gulf coast states vicinity. A trailing cold front will sweep southeast across the Southeast during the period, extending from southern GA into the northern Gulf of Mexico by Friday morning. Southerly low-level flow ahead of the front will allow upper 50s to near 60 F dewpoints to impinge on the central Gulf coast, with somewhat higher dewpoints expected across central/southern FL. While boundary-layer moisture will be greater across the FL Peninsula, poor lapse rates and relatively warm midlevel temperatures will result in capping and limit destabilization. A few lightning flashes may occur over parts of the Peninsula, but severe storms are not expected. ..Leitman.. 01/17/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1224 AM CST Wed Jan 17 2024 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Thursday. ...Synopsis... A shortwave upper trough embedded within a broader trough east of the Rockies will pivot east from the southern Plains to the Carolinas on Thursday. At the surface, a weak low will move in tandem with the shortwave impulse across the Gulf coast states vicinity. A trailing cold front will sweep southeast across the Southeast during the period, extending from southern GA into the northern Gulf of Mexico by Friday morning. Southerly low-level flow ahead of the front will allow upper 50s to near 60 F dewpoints to impinge on the central Gulf coast, with somewhat higher dewpoints expected across central/southern FL. While boundary-layer moisture will be greater across the FL Peninsula, poor lapse rates and relatively warm midlevel temperatures will result in capping and limit destabilization. A few lightning flashes may occur over parts of the Peninsula, but severe storms are not expected. ..Leitman.. 01/17/2024 Read more

MD 0077 CONCERNING HEAVY SNOW FOR DOWNSTREAM OF LAKES ONTARIO AND ERIE
Mesoscale Discussion 0077 NWS Storm Prediction Center Norman OK 0854 PM CST Tue Jan 16 2024 Areas affected...Downstream of Lakes Ontario and Erie Concerning...Heavy snow Valid 170254Z - 170730Z SUMMARY...An intense lake effect snow band off of Lake Ontario will persist through the overnight hours, with rates up to 2 in/hr. An additional lake effect band may intensify off of Lake Erie through the early morning hours. DISCUSSION...On the backside of a departing midlevel shortwave trough lifting northeastward across the Northeast, low/midlevel flow has become favorably aligned with the long axis of Lake Ontario, where an intense lake effect snow band has developed. Latest radar data and web cams suggest rates up to 2 in/hr over Oswego County with this organized band. Over the next few hours, low-level flow should remain unidirectional and maintain a favorable direction for the persistence of this band, with the heaviest snowfall rates expected over Oswego County. Rates up to 2 in/hr will be aided by persistent surface confluence along the lake and a modestly deep convective boundary layer extending up to about 2 km. In the 04-06Z time frame, low-level flow will back to a west-southwesterly direction, likely shifting the lake effect band northward into Jefferson County with time. However, increasing subsidence on the backside of the aforementioned midlevel trough could lead to decreased convective boundary layer depths and a slight reduction in rates. Off of Lake Erie, latest radar data shows some intensification of a lake effect snow band extending into Erie County. While low-level flow is modestly aligned with the long axis of the lake, the backing low-level winds with time should yield a more persistent band into the early morning hours. Thermodynamic conditions appear slightly less conducive compared to Lake Ontario, though rates could approach 2 in/hr if the snow band becomes persistent and organized. ..Weinman.. 01/17/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BGM...BUF... LAT...LON 43287614 43427682 43567703 43747686 43877642 43877607 43847576 43747538 43527526 43207551 43287614 Read more