Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Fri Jun 13 2025 Valid 131700Z - 141200Z ...CRITICAL FIRE WEATHER AREA FOR PARTS OF NORTHWESTERN NEVADA... The forecast remains on track, and no changes were needed with this update. For details, see the previous discussion below. ..Weinman.. 06/13/2025 .PREV DISCUSSION... /ISSUED 0212 AM CDT Fri Jun 13 2025/ ...Synopsis... A belt of southwesterly flow aloft with an embedded shortwave trough will be situated over the northwestern CONUS during the day. This will provide the focus for fire weather concerns, with the strong flow aloft mixing down due to strong surface heating, producing gusts of 25-30 mph across parts of northwestern Nevada. This will occur in the presence of 10-15% RH for several hours. Fuels in this area are fairly dry, so have maintained the Critical area across parts of northwestern Nevada. Similarly, modestly dry fuels along with gusty winds and 15-20% RH will result in Elevated fire conditions across portions of the Columbia Valley in Washington and Oregon. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Fri Jun 13 2025 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF CENTRAL AND SOUTHERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/southern Montana, where large to very large hail, severe winds, and a couple tornadoes will be possible. ...Central/southern MT this afternoon/evening... Embedded speed maxima will progress east-northeastward over the northern Rockies, with associated bands of ascent denoted by weak convection now over ID. Surface heating along and southwest of a baroclinic zone oriented from north central into southeast MT, and arrival of the bands of ascent from ID will contribute to thunderstorm development by early afternoon over the higher terrain of southwest MT. Storms will then spread eastward through the afternoon/evening, in an environment supportive of supercells on the northeast edge of the steeper midlevel lapse rates, in a corridor with long hodographs/effective bulk shear in excess of 50 kt. The strong deep-layer shear and moderate buoyancy (MLCAPE near 1500 J/kg) will favor large hail production, some greater than 2 inch diameter with the supercells, as well as damaging outflow gusts that could reach or exceed 75 mph. A couple of tornadoes will also be possible, though relatively deep mixing and relatively straight hodographs cast some doubt on the tornado threat. ...High Plains this afternoon into early tonight... Despite being near the crest of the midlevel ridge, sufficiently moist, low-level upslope flow and steep midlevel lapse rates will support thunderstorm development near and east of the lee trough from eastern WY to eastern CO/western KS and the northern TX Panhandle later this afternoon/evening. Deep mixing, steep lapse rates, and relatively weak vertical shear all support initial storms growing upscale into clusters through outflow interactions, and the clusters will spread southeastward into tonight. Isolated large hail will be possible with the stronger embedded storms, while severe outflow gusts will become the main concern with storm clusters this evening into early tonight. ...MS/AL to KY this afternoon... East of a weak midlevel trough from east TX to MO, modest enhancement of midlevel flow (to roughly 30-35 kt) and daytime heating of a moist air mass will contribute to scattered thunderstorm development through the afternoon from southeast LA/MS across northwest AL, TN and KY. MLCAPE of 1500-2500 J/kg and the aforementioned enhancement to midlevel flow will support storm clusters/line segments with some potential for isolated wind damage this afternoon. ...Mid-Atlantic this afternoon... Strong surface heating is underway to the south of a slow-moving front from DE into northern MD, which will steepen low-level lapse rates and boost MLCAPE to 1000-1500 J/kg this afternoon. Scattered thunderstorm development is possible along the front and the Blue Ridge, and storms will spread eastward through late afternoon/evening. The moderate buoyancy, steep low-level lapse rates and modest deep-layer vertical shear (effective bulk shear of 25-30 kt) will support some storm/cluster organization and the potential for isolated wind damage. ..Thompson/Barnes.. 06/13/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Fri Jun 13 2025 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF CENTRAL AND SOUTHERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/southern Montana, where large to very large hail, severe winds, and a couple tornadoes will be possible. ...Central/southern MT this afternoon/evening... Embedded speed maxima will progress east-northeastward over the northern Rockies, with associated bands of ascent denoted by weak convection now over ID. Surface heating along and southwest of a baroclinic zone oriented from north central into southeast MT, and arrival of the bands of ascent from ID will contribute to thunderstorm development by early afternoon over the higher terrain of southwest MT. Storms will then spread eastward through the afternoon/evening, in an environment supportive of supercells on the northeast edge of the steeper midlevel lapse rates, in a corridor with long hodographs/effective bulk shear in excess of 50 kt. The strong deep-layer shear and moderate buoyancy (MLCAPE near 1500 J/kg) will favor large hail production, some greater than 2 inch diameter with the supercells, as well as damaging outflow gusts that could reach or exceed 75 mph. A couple of tornadoes will also be possible, though relatively deep mixing and relatively straight hodographs cast some doubt on the tornado threat. ...High Plains this afternoon into early tonight... Despite being near the crest of the midlevel ridge, sufficiently moist, low-level upslope flow and steep midlevel lapse rates will support thunderstorm development near and east of the lee trough from eastern WY to eastern CO/western KS and the northern TX Panhandle later this afternoon/evening. Deep mixing, steep lapse rates, and relatively weak vertical shear all support initial storms growing upscale into clusters through outflow interactions, and the clusters will spread southeastward into tonight. Isolated large hail will be possible with the stronger embedded storms, while severe outflow gusts will become the main concern with storm clusters this evening into early tonight. ...MS/AL to KY this afternoon... East of a weak midlevel trough from east TX to MO, modest enhancement of midlevel flow (to roughly 30-35 kt) and daytime heating of a moist air mass will contribute to scattered thunderstorm development through the afternoon from southeast LA/MS across northwest AL, TN and KY. MLCAPE of 1500-2500 J/kg and the aforementioned enhancement to midlevel flow will support storm clusters/line segments with some potential for isolated wind damage this afternoon. ...Mid-Atlantic this afternoon... Strong surface heating is underway to the south of a slow-moving front from DE into northern MD, which will steepen low-level lapse rates and boost MLCAPE to 1000-1500 J/kg this afternoon. Scattered thunderstorm development is possible along the front and the Blue Ridge, and storms will spread eastward through late afternoon/evening. The moderate buoyancy, steep low-level lapse rates and modest deep-layer vertical shear (effective bulk shear of 25-30 kt) will support some storm/cluster organization and the potential for isolated wind damage. ..Thompson/Barnes.. 06/13/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Fri Jun 13 2025 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF CENTRAL AND SOUTHERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/southern Montana, where large to very large hail, severe winds, and a couple tornadoes will be possible. ...Central/southern MT this afternoon/evening... Embedded speed maxima will progress east-northeastward over the northern Rockies, with associated bands of ascent denoted by weak convection now over ID. Surface heating along and southwest of a baroclinic zone oriented from north central into southeast MT, and arrival of the bands of ascent from ID will contribute to thunderstorm development by early afternoon over the higher terrain of southwest MT. Storms will then spread eastward through the afternoon/evening, in an environment supportive of supercells on the northeast edge of the steeper midlevel lapse rates, in a corridor with long hodographs/effective bulk shear in excess of 50 kt. The strong deep-layer shear and moderate buoyancy (MLCAPE near 1500 J/kg) will favor large hail production, some greater than 2 inch diameter with the supercells, as well as damaging outflow gusts that could reach or exceed 75 mph. A couple of tornadoes will also be possible, though relatively deep mixing and relatively straight hodographs cast some doubt on the tornado threat. ...High Plains this afternoon into early tonight... Despite being near the crest of the midlevel ridge, sufficiently moist, low-level upslope flow and steep midlevel lapse rates will support thunderstorm development near and east of the lee trough from eastern WY to eastern CO/western KS and the northern TX Panhandle later this afternoon/evening. Deep mixing, steep lapse rates, and relatively weak vertical shear all support initial storms growing upscale into clusters through outflow interactions, and the clusters will spread southeastward into tonight. Isolated large hail will be possible with the stronger embedded storms, while severe outflow gusts will become the main concern with storm clusters this evening into early tonight. ...MS/AL to KY this afternoon... East of a weak midlevel trough from east TX to MO, modest enhancement of midlevel flow (to roughly 30-35 kt) and daytime heating of a moist air mass will contribute to scattered thunderstorm development through the afternoon from southeast LA/MS across northwest AL, TN and KY. MLCAPE of 1500-2500 J/kg and the aforementioned enhancement to midlevel flow will support storm clusters/line segments with some potential for isolated wind damage this afternoon. ...Mid-Atlantic this afternoon... Strong surface heating is underway to the south of a slow-moving front from DE into northern MD, which will steepen low-level lapse rates and boost MLCAPE to 1000-1500 J/kg this afternoon. Scattered thunderstorm development is possible along the front and the Blue Ridge, and storms will spread eastward through late afternoon/evening. The moderate buoyancy, steep low-level lapse rates and modest deep-layer vertical shear (effective bulk shear of 25-30 kt) will support some storm/cluster organization and the potential for isolated wind damage. ..Thompson/Barnes.. 06/13/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Fri Jun 13 2025 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF CENTRAL AND SOUTHERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/southern Montana, where large to very large hail, severe winds, and a couple tornadoes will be possible. ...Central/southern MT this afternoon/evening... Embedded speed maxima will progress east-northeastward over the northern Rockies, with associated bands of ascent denoted by weak convection now over ID. Surface heating along and southwest of a baroclinic zone oriented from north central into southeast MT, and arrival of the bands of ascent from ID will contribute to thunderstorm development by early afternoon over the higher terrain of southwest MT. Storms will then spread eastward through the afternoon/evening, in an environment supportive of supercells on the northeast edge of the steeper midlevel lapse rates, in a corridor with long hodographs/effective bulk shear in excess of 50 kt. The strong deep-layer shear and moderate buoyancy (MLCAPE near 1500 J/kg) will favor large hail production, some greater than 2 inch diameter with the supercells, as well as damaging outflow gusts that could reach or exceed 75 mph. A couple of tornadoes will also be possible, though relatively deep mixing and relatively straight hodographs cast some doubt on the tornado threat. ...High Plains this afternoon into early tonight... Despite being near the crest of the midlevel ridge, sufficiently moist, low-level upslope flow and steep midlevel lapse rates will support thunderstorm development near and east of the lee trough from eastern WY to eastern CO/western KS and the northern TX Panhandle later this afternoon/evening. Deep mixing, steep lapse rates, and relatively weak vertical shear all support initial storms growing upscale into clusters through outflow interactions, and the clusters will spread southeastward into tonight. Isolated large hail will be possible with the stronger embedded storms, while severe outflow gusts will become the main concern with storm clusters this evening into early tonight. ...MS/AL to KY this afternoon... East of a weak midlevel trough from east TX to MO, modest enhancement of midlevel flow (to roughly 30-35 kt) and daytime heating of a moist air mass will contribute to scattered thunderstorm development through the afternoon from southeast LA/MS across northwest AL, TN and KY. MLCAPE of 1500-2500 J/kg and the aforementioned enhancement to midlevel flow will support storm clusters/line segments with some potential for isolated wind damage this afternoon. ...Mid-Atlantic this afternoon... Strong surface heating is underway to the south of a slow-moving front from DE into northern MD, which will steepen low-level lapse rates and boost MLCAPE to 1000-1500 J/kg this afternoon. Scattered thunderstorm development is possible along the front and the Blue Ridge, and storms will spread eastward through late afternoon/evening. The moderate buoyancy, steep low-level lapse rates and modest deep-layer vertical shear (effective bulk shear of 25-30 kt) will support some storm/cluster organization and the potential for isolated wind damage. ..Thompson/Barnes.. 06/13/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Fri Jun 13 2025 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF CENTRAL AND SOUTHERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/southern Montana, where large to very large hail, severe winds, and a couple tornadoes will be possible. ...Central/southern MT this afternoon/evening... Embedded speed maxima will progress east-northeastward over the northern Rockies, with associated bands of ascent denoted by weak convection now over ID. Surface heating along and southwest of a baroclinic zone oriented from north central into southeast MT, and arrival of the bands of ascent from ID will contribute to thunderstorm development by early afternoon over the higher terrain of southwest MT. Storms will then spread eastward through the afternoon/evening, in an environment supportive of supercells on the northeast edge of the steeper midlevel lapse rates, in a corridor with long hodographs/effective bulk shear in excess of 50 kt. The strong deep-layer shear and moderate buoyancy (MLCAPE near 1500 J/kg) will favor large hail production, some greater than 2 inch diameter with the supercells, as well as damaging outflow gusts that could reach or exceed 75 mph. A couple of tornadoes will also be possible, though relatively deep mixing and relatively straight hodographs cast some doubt on the tornado threat. ...High Plains this afternoon into early tonight... Despite being near the crest of the midlevel ridge, sufficiently moist, low-level upslope flow and steep midlevel lapse rates will support thunderstorm development near and east of the lee trough from eastern WY to eastern CO/western KS and the northern TX Panhandle later this afternoon/evening. Deep mixing, steep lapse rates, and relatively weak vertical shear all support initial storms growing upscale into clusters through outflow interactions, and the clusters will spread southeastward into tonight. Isolated large hail will be possible with the stronger embedded storms, while severe outflow gusts will become the main concern with storm clusters this evening into early tonight. ...MS/AL to KY this afternoon... East of a weak midlevel trough from east TX to MO, modest enhancement of midlevel flow (to roughly 30-35 kt) and daytime heating of a moist air mass will contribute to scattered thunderstorm development through the afternoon from southeast LA/MS across northwest AL, TN and KY. MLCAPE of 1500-2500 J/kg and the aforementioned enhancement to midlevel flow will support storm clusters/line segments with some potential for isolated wind damage this afternoon. ...Mid-Atlantic this afternoon... Strong surface heating is underway to the south of a slow-moving front from DE into northern MD, which will steepen low-level lapse rates and boost MLCAPE to 1000-1500 J/kg this afternoon. Scattered thunderstorm development is possible along the front and the Blue Ridge, and storms will spread eastward through late afternoon/evening. The moderate buoyancy, steep low-level lapse rates and modest deep-layer vertical shear (effective bulk shear of 25-30 kt) will support some storm/cluster organization and the potential for isolated wind damage. ..Thompson/Barnes.. 06/13/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Fri Jun 13 2025 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF CENTRAL AND SOUTHERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/southern Montana, where large to very large hail, severe winds, and a couple tornadoes will be possible. ...Central/southern MT this afternoon/evening... Embedded speed maxima will progress east-northeastward over the northern Rockies, with associated bands of ascent denoted by weak convection now over ID. Surface heating along and southwest of a baroclinic zone oriented from north central into southeast MT, and arrival of the bands of ascent from ID will contribute to thunderstorm development by early afternoon over the higher terrain of southwest MT. Storms will then spread eastward through the afternoon/evening, in an environment supportive of supercells on the northeast edge of the steeper midlevel lapse rates, in a corridor with long hodographs/effective bulk shear in excess of 50 kt. The strong deep-layer shear and moderate buoyancy (MLCAPE near 1500 J/kg) will favor large hail production, some greater than 2 inch diameter with the supercells, as well as damaging outflow gusts that could reach or exceed 75 mph. A couple of tornadoes will also be possible, though relatively deep mixing and relatively straight hodographs cast some doubt on the tornado threat. ...High Plains this afternoon into early tonight... Despite being near the crest of the midlevel ridge, sufficiently moist, low-level upslope flow and steep midlevel lapse rates will support thunderstorm development near and east of the lee trough from eastern WY to eastern CO/western KS and the northern TX Panhandle later this afternoon/evening. Deep mixing, steep lapse rates, and relatively weak vertical shear all support initial storms growing upscale into clusters through outflow interactions, and the clusters will spread southeastward into tonight. Isolated large hail will be possible with the stronger embedded storms, while severe outflow gusts will become the main concern with storm clusters this evening into early tonight. ...MS/AL to KY this afternoon... East of a weak midlevel trough from east TX to MO, modest enhancement of midlevel flow (to roughly 30-35 kt) and daytime heating of a moist air mass will contribute to scattered thunderstorm development through the afternoon from southeast LA/MS across northwest AL, TN and KY. MLCAPE of 1500-2500 J/kg and the aforementioned enhancement to midlevel flow will support storm clusters/line segments with some potential for isolated wind damage this afternoon. ...Mid-Atlantic this afternoon... Strong surface heating is underway to the south of a slow-moving front from DE into northern MD, which will steepen low-level lapse rates and boost MLCAPE to 1000-1500 J/kg this afternoon. Scattered thunderstorm development is possible along the front and the Blue Ridge, and storms will spread eastward through late afternoon/evening. The moderate buoyancy, steep low-level lapse rates and modest deep-layer vertical shear (effective bulk shear of 25-30 kt) will support some storm/cluster organization and the potential for isolated wind damage. ..Thompson/Barnes.. 06/13/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Fri Jun 13 2025 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF CENTRAL AND SOUTHERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/southern Montana, where large to very large hail, severe winds, and a couple tornadoes will be possible. ...Central/southern MT this afternoon/evening... Embedded speed maxima will progress east-northeastward over the northern Rockies, with associated bands of ascent denoted by weak convection now over ID. Surface heating along and southwest of a baroclinic zone oriented from north central into southeast MT, and arrival of the bands of ascent from ID will contribute to thunderstorm development by early afternoon over the higher terrain of southwest MT. Storms will then spread eastward through the afternoon/evening, in an environment supportive of supercells on the northeast edge of the steeper midlevel lapse rates, in a corridor with long hodographs/effective bulk shear in excess of 50 kt. The strong deep-layer shear and moderate buoyancy (MLCAPE near 1500 J/kg) will favor large hail production, some greater than 2 inch diameter with the supercells, as well as damaging outflow gusts that could reach or exceed 75 mph. A couple of tornadoes will also be possible, though relatively deep mixing and relatively straight hodographs cast some doubt on the tornado threat. ...High Plains this afternoon into early tonight... Despite being near the crest of the midlevel ridge, sufficiently moist, low-level upslope flow and steep midlevel lapse rates will support thunderstorm development near and east of the lee trough from eastern WY to eastern CO/western KS and the northern TX Panhandle later this afternoon/evening. Deep mixing, steep lapse rates, and relatively weak vertical shear all support initial storms growing upscale into clusters through outflow interactions, and the clusters will spread southeastward into tonight. Isolated large hail will be possible with the stronger embedded storms, while severe outflow gusts will become the main concern with storm clusters this evening into early tonight. ...MS/AL to KY this afternoon... East of a weak midlevel trough from east TX to MO, modest enhancement of midlevel flow (to roughly 30-35 kt) and daytime heating of a moist air mass will contribute to scattered thunderstorm development through the afternoon from southeast LA/MS across northwest AL, TN and KY. MLCAPE of 1500-2500 J/kg and the aforementioned enhancement to midlevel flow will support storm clusters/line segments with some potential for isolated wind damage this afternoon. ...Mid-Atlantic this afternoon... Strong surface heating is underway to the south of a slow-moving front from DE into northern MD, which will steepen low-level lapse rates and boost MLCAPE to 1000-1500 J/kg this afternoon. Scattered thunderstorm development is possible along the front and the Blue Ridge, and storms will spread eastward through late afternoon/evening. The moderate buoyancy, steep low-level lapse rates and modest deep-layer vertical shear (effective bulk shear of 25-30 kt) will support some storm/cluster organization and the potential for isolated wind damage. ..Thompson/Barnes.. 06/13/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Fri Jun 13 2025 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF CENTRAL AND SOUTHERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/southern Montana, where large to very large hail, severe winds, and a couple tornadoes will be possible. ...Central/southern MT this afternoon/evening... Embedded speed maxima will progress east-northeastward over the northern Rockies, with associated bands of ascent denoted by weak convection now over ID. Surface heating along and southwest of a baroclinic zone oriented from north central into southeast MT, and arrival of the bands of ascent from ID will contribute to thunderstorm development by early afternoon over the higher terrain of southwest MT. Storms will then spread eastward through the afternoon/evening, in an environment supportive of supercells on the northeast edge of the steeper midlevel lapse rates, in a corridor with long hodographs/effective bulk shear in excess of 50 kt. The strong deep-layer shear and moderate buoyancy (MLCAPE near 1500 J/kg) will favor large hail production, some greater than 2 inch diameter with the supercells, as well as damaging outflow gusts that could reach or exceed 75 mph. A couple of tornadoes will also be possible, though relatively deep mixing and relatively straight hodographs cast some doubt on the tornado threat. ...High Plains this afternoon into early tonight... Despite being near the crest of the midlevel ridge, sufficiently moist, low-level upslope flow and steep midlevel lapse rates will support thunderstorm development near and east of the lee trough from eastern WY to eastern CO/western KS and the northern TX Panhandle later this afternoon/evening. Deep mixing, steep lapse rates, and relatively weak vertical shear all support initial storms growing upscale into clusters through outflow interactions, and the clusters will spread southeastward into tonight. Isolated large hail will be possible with the stronger embedded storms, while severe outflow gusts will become the main concern with storm clusters this evening into early tonight. ...MS/AL to KY this afternoon... East of a weak midlevel trough from east TX to MO, modest enhancement of midlevel flow (to roughly 30-35 kt) and daytime heating of a moist air mass will contribute to scattered thunderstorm development through the afternoon from southeast LA/MS across northwest AL, TN and KY. MLCAPE of 1500-2500 J/kg and the aforementioned enhancement to midlevel flow will support storm clusters/line segments with some potential for isolated wind damage this afternoon. ...Mid-Atlantic this afternoon... Strong surface heating is underway to the south of a slow-moving front from DE into northern MD, which will steepen low-level lapse rates and boost MLCAPE to 1000-1500 J/kg this afternoon. Scattered thunderstorm development is possible along the front and the Blue Ridge, and storms will spread eastward through late afternoon/evening. The moderate buoyancy, steep low-level lapse rates and modest deep-layer vertical shear (effective bulk shear of 25-30 kt) will support some storm/cluster organization and the potential for isolated wind damage. ..Thompson/Barnes.. 06/13/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Fri Jun 13 2025 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF CENTRAL AND SOUTHERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/southern Montana, where large to very large hail, severe winds, and a couple tornadoes will be possible. ...Central/southern MT this afternoon/evening... Embedded speed maxima will progress east-northeastward over the northern Rockies, with associated bands of ascent denoted by weak convection now over ID. Surface heating along and southwest of a baroclinic zone oriented from north central into southeast MT, and arrival of the bands of ascent from ID will contribute to thunderstorm development by early afternoon over the higher terrain of southwest MT. Storms will then spread eastward through the afternoon/evening, in an environment supportive of supercells on the northeast edge of the steeper midlevel lapse rates, in a corridor with long hodographs/effective bulk shear in excess of 50 kt. The strong deep-layer shear and moderate buoyancy (MLCAPE near 1500 J/kg) will favor large hail production, some greater than 2 inch diameter with the supercells, as well as damaging outflow gusts that could reach or exceed 75 mph. A couple of tornadoes will also be possible, though relatively deep mixing and relatively straight hodographs cast some doubt on the tornado threat. ...High Plains this afternoon into early tonight... Despite being near the crest of the midlevel ridge, sufficiently moist, low-level upslope flow and steep midlevel lapse rates will support thunderstorm development near and east of the lee trough from eastern WY to eastern CO/western KS and the northern TX Panhandle later this afternoon/evening. Deep mixing, steep lapse rates, and relatively weak vertical shear all support initial storms growing upscale into clusters through outflow interactions, and the clusters will spread southeastward into tonight. Isolated large hail will be possible with the stronger embedded storms, while severe outflow gusts will become the main concern with storm clusters this evening into early tonight. ...MS/AL to KY this afternoon... East of a weak midlevel trough from east TX to MO, modest enhancement of midlevel flow (to roughly 30-35 kt) and daytime heating of a moist air mass will contribute to scattered thunderstorm development through the afternoon from southeast LA/MS across northwest AL, TN and KY. MLCAPE of 1500-2500 J/kg and the aforementioned enhancement to midlevel flow will support storm clusters/line segments with some potential for isolated wind damage this afternoon. ...Mid-Atlantic this afternoon... Strong surface heating is underway to the south of a slow-moving front from DE into northern MD, which will steepen low-level lapse rates and boost MLCAPE to 1000-1500 J/kg this afternoon. Scattered thunderstorm development is possible along the front and the Blue Ridge, and storms will spread eastward through late afternoon/evening. The moderate buoyancy, steep low-level lapse rates and modest deep-layer vertical shear (effective bulk shear of 25-30 kt) will support some storm/cluster organization and the potential for isolated wind damage. ..Thompson/Barnes.. 06/13/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Fri Jun 13 2025 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF CENTRAL AND SOUTHERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/southern Montana, where large to very large hail, severe winds, and a couple tornadoes will be possible. ...Central/southern MT this afternoon/evening... Embedded speed maxima will progress east-northeastward over the northern Rockies, with associated bands of ascent denoted by weak convection now over ID. Surface heating along and southwest of a baroclinic zone oriented from north central into southeast MT, and arrival of the bands of ascent from ID will contribute to thunderstorm development by early afternoon over the higher terrain of southwest MT. Storms will then spread eastward through the afternoon/evening, in an environment supportive of supercells on the northeast edge of the steeper midlevel lapse rates, in a corridor with long hodographs/effective bulk shear in excess of 50 kt. The strong deep-layer shear and moderate buoyancy (MLCAPE near 1500 J/kg) will favor large hail production, some greater than 2 inch diameter with the supercells, as well as damaging outflow gusts that could reach or exceed 75 mph. A couple of tornadoes will also be possible, though relatively deep mixing and relatively straight hodographs cast some doubt on the tornado threat. ...High Plains this afternoon into early tonight... Despite being near the crest of the midlevel ridge, sufficiently moist, low-level upslope flow and steep midlevel lapse rates will support thunderstorm development near and east of the lee trough from eastern WY to eastern CO/western KS and the northern TX Panhandle later this afternoon/evening. Deep mixing, steep lapse rates, and relatively weak vertical shear all support initial storms growing upscale into clusters through outflow interactions, and the clusters will spread southeastward into tonight. Isolated large hail will be possible with the stronger embedded storms, while severe outflow gusts will become the main concern with storm clusters this evening into early tonight. ...MS/AL to KY this afternoon... East of a weak midlevel trough from east TX to MO, modest enhancement of midlevel flow (to roughly 30-35 kt) and daytime heating of a moist air mass will contribute to scattered thunderstorm development through the afternoon from southeast LA/MS across northwest AL, TN and KY. MLCAPE of 1500-2500 J/kg and the aforementioned enhancement to midlevel flow will support storm clusters/line segments with some potential for isolated wind damage this afternoon. ...Mid-Atlantic this afternoon... Strong surface heating is underway to the south of a slow-moving front from DE into northern MD, which will steepen low-level lapse rates and boost MLCAPE to 1000-1500 J/kg this afternoon. Scattered thunderstorm development is possible along the front and the Blue Ridge, and storms will spread eastward through late afternoon/evening. The moderate buoyancy, steep low-level lapse rates and modest deep-layer vertical shear (effective bulk shear of 25-30 kt) will support some storm/cluster organization and the potential for isolated wind damage. ..Thompson/Barnes.. 06/13/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Fri Jun 13 2025 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF CENTRAL AND SOUTHERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/southern Montana, where large to very large hail, severe winds, and a couple tornadoes will be possible. ...Central/southern MT this afternoon/evening... Embedded speed maxima will progress east-northeastward over the northern Rockies, with associated bands of ascent denoted by weak convection now over ID. Surface heating along and southwest of a baroclinic zone oriented from north central into southeast MT, and arrival of the bands of ascent from ID will contribute to thunderstorm development by early afternoon over the higher terrain of southwest MT. Storms will then spread eastward through the afternoon/evening, in an environment supportive of supercells on the northeast edge of the steeper midlevel lapse rates, in a corridor with long hodographs/effective bulk shear in excess of 50 kt. The strong deep-layer shear and moderate buoyancy (MLCAPE near 1500 J/kg) will favor large hail production, some greater than 2 inch diameter with the supercells, as well as damaging outflow gusts that could reach or exceed 75 mph. A couple of tornadoes will also be possible, though relatively deep mixing and relatively straight hodographs cast some doubt on the tornado threat. ...High Plains this afternoon into early tonight... Despite being near the crest of the midlevel ridge, sufficiently moist, low-level upslope flow and steep midlevel lapse rates will support thunderstorm development near and east of the lee trough from eastern WY to eastern CO/western KS and the northern TX Panhandle later this afternoon/evening. Deep mixing, steep lapse rates, and relatively weak vertical shear all support initial storms growing upscale into clusters through outflow interactions, and the clusters will spread southeastward into tonight. Isolated large hail will be possible with the stronger embedded storms, while severe outflow gusts will become the main concern with storm clusters this evening into early tonight. ...MS/AL to KY this afternoon... East of a weak midlevel trough from east TX to MO, modest enhancement of midlevel flow (to roughly 30-35 kt) and daytime heating of a moist air mass will contribute to scattered thunderstorm development through the afternoon from southeast LA/MS across northwest AL, TN and KY. MLCAPE of 1500-2500 J/kg and the aforementioned enhancement to midlevel flow will support storm clusters/line segments with some potential for isolated wind damage this afternoon. ...Mid-Atlantic this afternoon... Strong surface heating is underway to the south of a slow-moving front from DE into northern MD, which will steepen low-level lapse rates and boost MLCAPE to 1000-1500 J/kg this afternoon. Scattered thunderstorm development is possible along the front and the Blue Ridge, and storms will spread eastward through late afternoon/evening. The moderate buoyancy, steep low-level lapse rates and modest deep-layer vertical shear (effective bulk shear of 25-30 kt) will support some storm/cluster organization and the potential for isolated wind damage. ..Thompson/Barnes.. 06/13/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Fri Jun 13 2025 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF CENTRAL AND SOUTHERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/southern Montana, where large to very large hail, severe winds, and a couple tornadoes will be possible. ...Central/southern MT this afternoon/evening... Embedded speed maxima will progress east-northeastward over the northern Rockies, with associated bands of ascent denoted by weak convection now over ID. Surface heating along and southwest of a baroclinic zone oriented from north central into southeast MT, and arrival of the bands of ascent from ID will contribute to thunderstorm development by early afternoon over the higher terrain of southwest MT. Storms will then spread eastward through the afternoon/evening, in an environment supportive of supercells on the northeast edge of the steeper midlevel lapse rates, in a corridor with long hodographs/effective bulk shear in excess of 50 kt. The strong deep-layer shear and moderate buoyancy (MLCAPE near 1500 J/kg) will favor large hail production, some greater than 2 inch diameter with the supercells, as well as damaging outflow gusts that could reach or exceed 75 mph. A couple of tornadoes will also be possible, though relatively deep mixing and relatively straight hodographs cast some doubt on the tornado threat. ...High Plains this afternoon into early tonight... Despite being near the crest of the midlevel ridge, sufficiently moist, low-level upslope flow and steep midlevel lapse rates will support thunderstorm development near and east of the lee trough from eastern WY to eastern CO/western KS and the northern TX Panhandle later this afternoon/evening. Deep mixing, steep lapse rates, and relatively weak vertical shear all support initial storms growing upscale into clusters through outflow interactions, and the clusters will spread southeastward into tonight. Isolated large hail will be possible with the stronger embedded storms, while severe outflow gusts will become the main concern with storm clusters this evening into early tonight. ...MS/AL to KY this afternoon... East of a weak midlevel trough from east TX to MO, modest enhancement of midlevel flow (to roughly 30-35 kt) and daytime heating of a moist air mass will contribute to scattered thunderstorm development through the afternoon from southeast LA/MS across northwest AL, TN and KY. MLCAPE of 1500-2500 J/kg and the aforementioned enhancement to midlevel flow will support storm clusters/line segments with some potential for isolated wind damage this afternoon. ...Mid-Atlantic this afternoon... Strong surface heating is underway to the south of a slow-moving front from DE into northern MD, which will steepen low-level lapse rates and boost MLCAPE to 1000-1500 J/kg this afternoon. Scattered thunderstorm development is possible along the front and the Blue Ridge, and storms will spread eastward through late afternoon/evening. The moderate buoyancy, steep low-level lapse rates and modest deep-layer vertical shear (effective bulk shear of 25-30 kt) will support some storm/cluster organization and the potential for isolated wind damage. ..Thompson/Barnes.. 06/13/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Fri Jun 13 2025 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF CENTRAL AND SOUTHERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/southern Montana, where large to very large hail, severe winds, and a couple tornadoes will be possible. ...Central/southern MT this afternoon/evening... Embedded speed maxima will progress east-northeastward over the northern Rockies, with associated bands of ascent denoted by weak convection now over ID. Surface heating along and southwest of a baroclinic zone oriented from north central into southeast MT, and arrival of the bands of ascent from ID will contribute to thunderstorm development by early afternoon over the higher terrain of southwest MT. Storms will then spread eastward through the afternoon/evening, in an environment supportive of supercells on the northeast edge of the steeper midlevel lapse rates, in a corridor with long hodographs/effective bulk shear in excess of 50 kt. The strong deep-layer shear and moderate buoyancy (MLCAPE near 1500 J/kg) will favor large hail production, some greater than 2 inch diameter with the supercells, as well as damaging outflow gusts that could reach or exceed 75 mph. A couple of tornadoes will also be possible, though relatively deep mixing and relatively straight hodographs cast some doubt on the tornado threat. ...High Plains this afternoon into early tonight... Despite being near the crest of the midlevel ridge, sufficiently moist, low-level upslope flow and steep midlevel lapse rates will support thunderstorm development near and east of the lee trough from eastern WY to eastern CO/western KS and the northern TX Panhandle later this afternoon/evening. Deep mixing, steep lapse rates, and relatively weak vertical shear all support initial storms growing upscale into clusters through outflow interactions, and the clusters will spread southeastward into tonight. Isolated large hail will be possible with the stronger embedded storms, while severe outflow gusts will become the main concern with storm clusters this evening into early tonight. ...MS/AL to KY this afternoon... East of a weak midlevel trough from east TX to MO, modest enhancement of midlevel flow (to roughly 30-35 kt) and daytime heating of a moist air mass will contribute to scattered thunderstorm development through the afternoon from southeast LA/MS across northwest AL, TN and KY. MLCAPE of 1500-2500 J/kg and the aforementioned enhancement to midlevel flow will support storm clusters/line segments with some potential for isolated wind damage this afternoon. ...Mid-Atlantic this afternoon... Strong surface heating is underway to the south of a slow-moving front from DE into northern MD, which will steepen low-level lapse rates and boost MLCAPE to 1000-1500 J/kg this afternoon. Scattered thunderstorm development is possible along the front and the Blue Ridge, and storms will spread eastward through late afternoon/evening. The moderate buoyancy, steep low-level lapse rates and modest deep-layer vertical shear (effective bulk shear of 25-30 kt) will support some storm/cluster organization and the potential for isolated wind damage. ..Thompson/Barnes.. 06/13/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Fri Jun 13 2025 Valid 131630Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF CENTRAL AND SOUTHERN MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/southern Montana, where large to very large hail, severe winds, and a couple tornadoes will be possible. ...Central/southern MT this afternoon/evening... Embedded speed maxima will progress east-northeastward over the northern Rockies, with associated bands of ascent denoted by weak convection now over ID. Surface heating along and southwest of a baroclinic zone oriented from north central into southeast MT, and arrival of the bands of ascent from ID will contribute to thunderstorm development by early afternoon over the higher terrain of southwest MT. Storms will then spread eastward through the afternoon/evening, in an environment supportive of supercells on the northeast edge of the steeper midlevel lapse rates, in a corridor with long hodographs/effective bulk shear in excess of 50 kt. The strong deep-layer shear and moderate buoyancy (MLCAPE near 1500 J/kg) will favor large hail production, some greater than 2 inch diameter with the supercells, as well as damaging outflow gusts that could reach or exceed 75 mph. A couple of tornadoes will also be possible, though relatively deep mixing and relatively straight hodographs cast some doubt on the tornado threat. ...High Plains this afternoon into early tonight... Despite being near the crest of the midlevel ridge, sufficiently moist, low-level upslope flow and steep midlevel lapse rates will support thunderstorm development near and east of the lee trough from eastern WY to eastern CO/western KS and the northern TX Panhandle later this afternoon/evening. Deep mixing, steep lapse rates, and relatively weak vertical shear all support initial storms growing upscale into clusters through outflow interactions, and the clusters will spread southeastward into tonight. Isolated large hail will be possible with the stronger embedded storms, while severe outflow gusts will become the main concern with storm clusters this evening into early tonight. ...MS/AL to KY this afternoon... East of a weak midlevel trough from east TX to MO, modest enhancement of midlevel flow (to roughly 30-35 kt) and daytime heating of a moist air mass will contribute to scattered thunderstorm development through the afternoon from southeast LA/MS across northwest AL, TN and KY. MLCAPE of 1500-2500 J/kg and the aforementioned enhancement to midlevel flow will support storm clusters/line segments with some potential for isolated wind damage this afternoon. ...Mid-Atlantic this afternoon... Strong surface heating is underway to the south of a slow-moving front from DE into northern MD, which will steepen low-level lapse rates and boost MLCAPE to 1000-1500 J/kg this afternoon. Scattered thunderstorm development is possible along the front and the Blue Ridge, and storms will spread eastward through late afternoon/evening. The moderate buoyancy, steep low-level lapse rates and modest deep-layer vertical shear (effective bulk shear of 25-30 kt) will support some storm/cluster organization and the potential for isolated wind damage. ..Thompson/Barnes.. 06/13/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0740 AM CDT Fri Jun 13 2025 Valid 131300Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/eastern Montana, where large to very large hail, severe winds, and perhaps a few tornadoes are anticipated. ...Northern Rockies/High Plains... A closed upper low will remain centered off the coast of British Columbia today, as multiple low-amplitude mid-level shortwave troughs advance eastward across the Pacific Northwest to the northern Rockies. A seasonably moist low-level airmass is already in place this morning across much of MT, with surface dewpoints generally in the 50s. Daytime heating and modestly steepened mid-level lapse rates will aid in the development of moderate instability by this afternoon, mainly from central MT eastward. 35-50 kt of west-southwesterly mid-level flow associated with the shortwave troughs should support similar values of deep-layer shear, with RAP forecast soundings showing long/straight hodographs at mid/upper levels. Large-scale ascent attendant to the shortwave troughs will likely encourage robust convective development by early afternoon (18-20Z), initially over the higher terrain of the northern Rockies. This activity is forecast to quickly become supercellular given moderate to strong effective bulk shear. The favorable lapse rates and hodographs at mid/upper levels should support a threat for scattered large to isolated very large (2+ inch diameter) hail with this initially cellular activity. By mid to late afternoon into early evening, some clustering/upscale growth is anticipated across eastern MT and vicinity as low-level southeasterly flow gradually strengthens. A greater threat for severe/damaging winds, with isolated gusts of 75+ mph, remains apparent across this area. The tornado threat is less clear, as the boundary layer is forecast to become rather well mixed this afternoon. Still, modestly increasing low-level shear this evening may support some threat for a few tornadoes. ...Central/Southern High Plains into Western Arkansas... Elevated convection ongoing this morning across western OK in a modest low-level warm advection regime may pose a limited severe threat until it diminishes later this morning. Otherwise, at least scattered thunderstorms should develop over the higher terrain of the central Rockies and subsequently spread eastward into the adjacent High Plains this afternoon and evening. Mid-level west-southwesterly flow is generally expected to weaken with southward extent across the central High Plains. But, sufficient directional shear should still exist to support some updraft organization, including the potential for a few supercells across eastern WY/CO into western SD/NE/KS. Isolated large hail will be a threat with any convection that can remain at least semi-discrete, while severe winds may occur with one or more clusters that eventually develop. Convection is expected to become more isolated and less organized with southward extent into the southern High Plains, but it may still pose some hail/wind threat given sufficient instability and steepened low/mid-level lapse rates. Somewhat stronger northwesterly mid-level flow should also be in place across OK into western AR on the back side of an upper trough over the lower/mid MS Valley. While forcing will remain weak/nebulous across this region, a conditionally favorable environment for severe thunderstorms will exist. ...Lower Mississippi Valley/Southeast into the Ohio Valley... A weak mid-level trough will advance slowly eastward from the Ozarks to the lower MS and OH Valleys through the period. Around 25-35 kt of southwesterly mid-level flow will be present over these regions as filtered daytime heating of a rather moist low-level airmass occurs today. Even though lapse rates aloft are forecast to remain poor, sufficient instability and deep-layer shear should exist to support an isolated threat for mainly damaging winds this afternoon and early evening as low-level lapse rates steepen. A Marginal Risk has been included with this update across parts of the lower MS Valley/Southeast into the OH Valley, where confidence in loosely organized clusters occurring is greatest. ..Gleason/Kerr.. 06/13/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0740 AM CDT Fri Jun 13 2025 Valid 131300Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/eastern Montana, where large to very large hail, severe winds, and perhaps a few tornadoes are anticipated. ...Northern Rockies/High Plains... A closed upper low will remain centered off the coast of British Columbia today, as multiple low-amplitude mid-level shortwave troughs advance eastward across the Pacific Northwest to the northern Rockies. A seasonably moist low-level airmass is already in place this morning across much of MT, with surface dewpoints generally in the 50s. Daytime heating and modestly steepened mid-level lapse rates will aid in the development of moderate instability by this afternoon, mainly from central MT eastward. 35-50 kt of west-southwesterly mid-level flow associated with the shortwave troughs should support similar values of deep-layer shear, with RAP forecast soundings showing long/straight hodographs at mid/upper levels. Large-scale ascent attendant to the shortwave troughs will likely encourage robust convective development by early afternoon (18-20Z), initially over the higher terrain of the northern Rockies. This activity is forecast to quickly become supercellular given moderate to strong effective bulk shear. The favorable lapse rates and hodographs at mid/upper levels should support a threat for scattered large to isolated very large (2+ inch diameter) hail with this initially cellular activity. By mid to late afternoon into early evening, some clustering/upscale growth is anticipated across eastern MT and vicinity as low-level southeasterly flow gradually strengthens. A greater threat for severe/damaging winds, with isolated gusts of 75+ mph, remains apparent across this area. The tornado threat is less clear, as the boundary layer is forecast to become rather well mixed this afternoon. Still, modestly increasing low-level shear this evening may support some threat for a few tornadoes. ...Central/Southern High Plains into Western Arkansas... Elevated convection ongoing this morning across western OK in a modest low-level warm advection regime may pose a limited severe threat until it diminishes later this morning. Otherwise, at least scattered thunderstorms should develop over the higher terrain of the central Rockies and subsequently spread eastward into the adjacent High Plains this afternoon and evening. Mid-level west-southwesterly flow is generally expected to weaken with southward extent across the central High Plains. But, sufficient directional shear should still exist to support some updraft organization, including the potential for a few supercells across eastern WY/CO into western SD/NE/KS. Isolated large hail will be a threat with any convection that can remain at least semi-discrete, while severe winds may occur with one or more clusters that eventually develop. Convection is expected to become more isolated and less organized with southward extent into the southern High Plains, but it may still pose some hail/wind threat given sufficient instability and steepened low/mid-level lapse rates. Somewhat stronger northwesterly mid-level flow should also be in place across OK into western AR on the back side of an upper trough over the lower/mid MS Valley. While forcing will remain weak/nebulous across this region, a conditionally favorable environment for severe thunderstorms will exist. ...Lower Mississippi Valley/Southeast into the Ohio Valley... A weak mid-level trough will advance slowly eastward from the Ozarks to the lower MS and OH Valleys through the period. Around 25-35 kt of southwesterly mid-level flow will be present over these regions as filtered daytime heating of a rather moist low-level airmass occurs today. Even though lapse rates aloft are forecast to remain poor, sufficient instability and deep-layer shear should exist to support an isolated threat for mainly damaging winds this afternoon and early evening as low-level lapse rates steepen. A Marginal Risk has been included with this update across parts of the lower MS Valley/Southeast into the OH Valley, where confidence in loosely organized clusters occurring is greatest. ..Gleason/Kerr.. 06/13/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0740 AM CDT Fri Jun 13 2025 Valid 131300Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/eastern Montana, where large to very large hail, severe winds, and perhaps a few tornadoes are anticipated. ...Northern Rockies/High Plains... A closed upper low will remain centered off the coast of British Columbia today, as multiple low-amplitude mid-level shortwave troughs advance eastward across the Pacific Northwest to the northern Rockies. A seasonably moist low-level airmass is already in place this morning across much of MT, with surface dewpoints generally in the 50s. Daytime heating and modestly steepened mid-level lapse rates will aid in the development of moderate instability by this afternoon, mainly from central MT eastward. 35-50 kt of west-southwesterly mid-level flow associated with the shortwave troughs should support similar values of deep-layer shear, with RAP forecast soundings showing long/straight hodographs at mid/upper levels. Large-scale ascent attendant to the shortwave troughs will likely encourage robust convective development by early afternoon (18-20Z), initially over the higher terrain of the northern Rockies. This activity is forecast to quickly become supercellular given moderate to strong effective bulk shear. The favorable lapse rates and hodographs at mid/upper levels should support a threat for scattered large to isolated very large (2+ inch diameter) hail with this initially cellular activity. By mid to late afternoon into early evening, some clustering/upscale growth is anticipated across eastern MT and vicinity as low-level southeasterly flow gradually strengthens. A greater threat for severe/damaging winds, with isolated gusts of 75+ mph, remains apparent across this area. The tornado threat is less clear, as the boundary layer is forecast to become rather well mixed this afternoon. Still, modestly increasing low-level shear this evening may support some threat for a few tornadoes. ...Central/Southern High Plains into Western Arkansas... Elevated convection ongoing this morning across western OK in a modest low-level warm advection regime may pose a limited severe threat until it diminishes later this morning. Otherwise, at least scattered thunderstorms should develop over the higher terrain of the central Rockies and subsequently spread eastward into the adjacent High Plains this afternoon and evening. Mid-level west-southwesterly flow is generally expected to weaken with southward extent across the central High Plains. But, sufficient directional shear should still exist to support some updraft organization, including the potential for a few supercells across eastern WY/CO into western SD/NE/KS. Isolated large hail will be a threat with any convection that can remain at least semi-discrete, while severe winds may occur with one or more clusters that eventually develop. Convection is expected to become more isolated and less organized with southward extent into the southern High Plains, but it may still pose some hail/wind threat given sufficient instability and steepened low/mid-level lapse rates. Somewhat stronger northwesterly mid-level flow should also be in place across OK into western AR on the back side of an upper trough over the lower/mid MS Valley. While forcing will remain weak/nebulous across this region, a conditionally favorable environment for severe thunderstorms will exist. ...Lower Mississippi Valley/Southeast into the Ohio Valley... A weak mid-level trough will advance slowly eastward from the Ozarks to the lower MS and OH Valleys through the period. Around 25-35 kt of southwesterly mid-level flow will be present over these regions as filtered daytime heating of a rather moist low-level airmass occurs today. Even though lapse rates aloft are forecast to remain poor, sufficient instability and deep-layer shear should exist to support an isolated threat for mainly damaging winds this afternoon and early evening as low-level lapse rates steepen. A Marginal Risk has been included with this update across parts of the lower MS Valley/Southeast into the OH Valley, where confidence in loosely organized clusters occurring is greatest. ..Gleason/Kerr.. 06/13/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0740 AM CDT Fri Jun 13 2025 Valid 131300Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/eastern Montana, where large to very large hail, severe winds, and perhaps a few tornadoes are anticipated. ...Northern Rockies/High Plains... A closed upper low will remain centered off the coast of British Columbia today, as multiple low-amplitude mid-level shortwave troughs advance eastward across the Pacific Northwest to the northern Rockies. A seasonably moist low-level airmass is already in place this morning across much of MT, with surface dewpoints generally in the 50s. Daytime heating and modestly steepened mid-level lapse rates will aid in the development of moderate instability by this afternoon, mainly from central MT eastward. 35-50 kt of west-southwesterly mid-level flow associated with the shortwave troughs should support similar values of deep-layer shear, with RAP forecast soundings showing long/straight hodographs at mid/upper levels. Large-scale ascent attendant to the shortwave troughs will likely encourage robust convective development by early afternoon (18-20Z), initially over the higher terrain of the northern Rockies. This activity is forecast to quickly become supercellular given moderate to strong effective bulk shear. The favorable lapse rates and hodographs at mid/upper levels should support a threat for scattered large to isolated very large (2+ inch diameter) hail with this initially cellular activity. By mid to late afternoon into early evening, some clustering/upscale growth is anticipated across eastern MT and vicinity as low-level southeasterly flow gradually strengthens. A greater threat for severe/damaging winds, with isolated gusts of 75+ mph, remains apparent across this area. The tornado threat is less clear, as the boundary layer is forecast to become rather well mixed this afternoon. Still, modestly increasing low-level shear this evening may support some threat for a few tornadoes. ...Central/Southern High Plains into Western Arkansas... Elevated convection ongoing this morning across western OK in a modest low-level warm advection regime may pose a limited severe threat until it diminishes later this morning. Otherwise, at least scattered thunderstorms should develop over the higher terrain of the central Rockies and subsequently spread eastward into the adjacent High Plains this afternoon and evening. Mid-level west-southwesterly flow is generally expected to weaken with southward extent across the central High Plains. But, sufficient directional shear should still exist to support some updraft organization, including the potential for a few supercells across eastern WY/CO into western SD/NE/KS. Isolated large hail will be a threat with any convection that can remain at least semi-discrete, while severe winds may occur with one or more clusters that eventually develop. Convection is expected to become more isolated and less organized with southward extent into the southern High Plains, but it may still pose some hail/wind threat given sufficient instability and steepened low/mid-level lapse rates. Somewhat stronger northwesterly mid-level flow should also be in place across OK into western AR on the back side of an upper trough over the lower/mid MS Valley. While forcing will remain weak/nebulous across this region, a conditionally favorable environment for severe thunderstorms will exist. ...Lower Mississippi Valley/Southeast into the Ohio Valley... A weak mid-level trough will advance slowly eastward from the Ozarks to the lower MS and OH Valleys through the period. Around 25-35 kt of southwesterly mid-level flow will be present over these regions as filtered daytime heating of a rather moist low-level airmass occurs today. Even though lapse rates aloft are forecast to remain poor, sufficient instability and deep-layer shear should exist to support an isolated threat for mainly damaging winds this afternoon and early evening as low-level lapse rates steepen. A Marginal Risk has been included with this update across parts of the lower MS Valley/Southeast into the OH Valley, where confidence in loosely organized clusters occurring is greatest. ..Gleason/Kerr.. 06/13/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0740 AM CDT Fri Jun 13 2025 Valid 131300Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF MONTANA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of Montana, extending southward across portions of the central/southern High Plains. The greatest concentration of severe thunderstorms should occur across central/eastern Montana, where large to very large hail, severe winds, and perhaps a few tornadoes are anticipated. ...Northern Rockies/High Plains... A closed upper low will remain centered off the coast of British Columbia today, as multiple low-amplitude mid-level shortwave troughs advance eastward across the Pacific Northwest to the northern Rockies. A seasonably moist low-level airmass is already in place this morning across much of MT, with surface dewpoints generally in the 50s. Daytime heating and modestly steepened mid-level lapse rates will aid in the development of moderate instability by this afternoon, mainly from central MT eastward. 35-50 kt of west-southwesterly mid-level flow associated with the shortwave troughs should support similar values of deep-layer shear, with RAP forecast soundings showing long/straight hodographs at mid/upper levels. Large-scale ascent attendant to the shortwave troughs will likely encourage robust convective development by early afternoon (18-20Z), initially over the higher terrain of the northern Rockies. This activity is forecast to quickly become supercellular given moderate to strong effective bulk shear. The favorable lapse rates and hodographs at mid/upper levels should support a threat for scattered large to isolated very large (2+ inch diameter) hail with this initially cellular activity. By mid to late afternoon into early evening, some clustering/upscale growth is anticipated across eastern MT and vicinity as low-level southeasterly flow gradually strengthens. A greater threat for severe/damaging winds, with isolated gusts of 75+ mph, remains apparent across this area. The tornado threat is less clear, as the boundary layer is forecast to become rather well mixed this afternoon. Still, modestly increasing low-level shear this evening may support some threat for a few tornadoes. ...Central/Southern High Plains into Western Arkansas... Elevated convection ongoing this morning across western OK in a modest low-level warm advection regime may pose a limited severe threat until it diminishes later this morning. Otherwise, at least scattered thunderstorms should develop over the higher terrain of the central Rockies and subsequently spread eastward into the adjacent High Plains this afternoon and evening. Mid-level west-southwesterly flow is generally expected to weaken with southward extent across the central High Plains. But, sufficient directional shear should still exist to support some updraft organization, including the potential for a few supercells across eastern WY/CO into western SD/NE/KS. Isolated large hail will be a threat with any convection that can remain at least semi-discrete, while severe winds may occur with one or more clusters that eventually develop. Convection is expected to become more isolated and less organized with southward extent into the southern High Plains, but it may still pose some hail/wind threat given sufficient instability and steepened low/mid-level lapse rates. Somewhat stronger northwesterly mid-level flow should also be in place across OK into western AR on the back side of an upper trough over the lower/mid MS Valley. While forcing will remain weak/nebulous across this region, a conditionally favorable environment for severe thunderstorms will exist. ...Lower Mississippi Valley/Southeast into the Ohio Valley... A weak mid-level trough will advance slowly eastward from the Ozarks to the lower MS and OH Valleys through the period. Around 25-35 kt of southwesterly mid-level flow will be present over these regions as filtered daytime heating of a rather moist low-level airmass occurs today. Even though lapse rates aloft are forecast to remain poor, sufficient instability and deep-layer shear should exist to support an isolated threat for mainly damaging winds this afternoon and early evening as low-level lapse rates steepen. A Marginal Risk has been included with this update across parts of the lower MS Valley/Southeast into the OH Valley, where confidence in loosely organized clusters occurring is greatest. ..Gleason/Kerr.. 06/13/2025 Read more