Severe Storms

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

MD 1804 CONCERNING SEVERE THUNDERSTORM WATCH 545... FOR NORTHEAST MONTANA INTO NORTHWEST NORTH DAKOTA
Mesoscale Discussion 1804 NWS Storm Prediction Center Norman OK 1128 PM CDT Sat Jul 26 2025 Areas affected...Northeast Montana into northwest North Dakota Concerning...Severe Thunderstorm Watch 545... Valid 270428Z - 270600Z The severe weather threat for Severe Thunderstorm Watch 545 continues. SUMMARY...An MCS with a history of producing severe winds is expected to spread into northwest/western North Dakota through the early morning hours. Downstream watch issuance is being considered, though confidence in MCS intensity is waning to some degree. DISCUSSION...The MCS moving across northeast MT has a history of producing 50-56 knot winds within the past few hours. However, more recent radar imagery from KGGW shows the MCS has become outflow dominant with a decrease in lightning activity noted as well. This casts some uncertainty onto how intense the MCS will be in the coming hours as it pushes into northwest ND where inhibition is slowly increasing with the onset of nocturnal cooling. Reflectivity composites and GOES IR imagery both show strong embedded updrafts within this line, and rich low-level moisture remains in place immediately downstream. Recent radar trends also show the deeper/stronger convective cores developing slightly southward towards the better buoyancy/moisture, hinting that the MCS may propagate along the buoyancy axis in place across west-central ND. As such, there remains some potential for a severe wind threat with this MCS as it moves east over the coming hours, though the magnitude/coverage of severe winds appears uncertain at this time. Regardless, watch issuance is being considered for northwest/western ND. ..Moore.. 07/27/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BIS...BYZ...GGW... LAT...LON 47100676 47300643 47720640 48080642 48340653 48670643 48760300 48710268 48550246 47640240 47060256 46820285 46690328 46660400 46840670 46960685 47100676 MOST PROBABLE PEAK WIND GUST...55-70 MPH Read more

MD 1803 CONCERNING SEVERE THUNDERSTORM WATCH 546... FOR PORTIONS OF THE EASTERN DAKOTAS
Mesoscale Discussion 1803 NWS Storm Prediction Center Norman OK 1059 PM CDT Sat Jul 26 2025 Areas affected...Portions of the eastern Dakotas Concerning...Severe Thunderstorm Watch 546... Valid 270359Z - 270600Z The severe weather threat for Severe Thunderstorm Watch 546 continues. SUMMARY...Strong to severe thunderstorms will continue to spread north and east into eastern North Dakota and northeast South Dakota through the overnight hours. Downstream watch issuance and/or expansions are expected in the next couple of hours. DISCUSSION...Regional radar trends show initially discrete cells from southern ND and central SD transitioning into semi-organize convective clusters/lines. Recent severe wind reports have been noted with one such cluster moving across central SD within the past hour. This activity is slowly moving into a more capped environment with diminishing deep-layer wind shear; however, cold-pool propagation into an otherwise buoyant environment should help maintain this activity into the early morning hours with an attendant threat for severe winds. Further north, convection building across southern ND is expected to continue spreading north/northeast within a zone of weak isentropic ascent between 925-850 mb. This zone is co-located with a regional buoyancy maximum across east/southeast ND and where stronger mid-level flow is supporting effective shear values of around 35-40 knots. As such, a mix of strong to severe clusters and embedded supercells is likely heading into the early morning hours. Downstream watch issuance is expected given the potential for severe gusts and large hail. ..Moore.. 07/27/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGF...FSD...ABR...BIS... LAT...LON 44609957 45149914 45549901 45899910 46159919 46309958 46340007 46300042 46250081 46290102 46430119 46670118 47310072 47630023 47889937 47899874 47809815 47689777 47459728 47089685 46809666 46429656 46069653 45169660 44899670 44609688 44419722 44249769 44169806 44169865 44229909 44409941 44529954 44609957 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN Read more

WW 0545 Status Updates
STATUS REPORT ON WW 545 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 WSW GDV TO 55 N GGW. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1804. ..GRAMS..07/27/25 ATTN...WFO...TFX...GGW...BYZ... STATUS REPORT FOR WS 545 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC019-021-055-079-083-085-091-109-270640- MT . MONTANA COUNTIES INCLUDED ARE DANIELS DAWSON MCCONE PRAIRIE RICHLAND ROOSEVELT SHERIDAN WIBAUX THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0547 Status Updates
STATUS FOR WATCH 0547 HAS NOT BEEN ISSUED YET Read more

WW 0547 Status Updates
STATUS FOR WATCH 0547 HAS NOT BEEN ISSUED YET Read more

WW 0546 Status Updates
STATUS REPORT ON WW 546 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 W PHP TO 30 WNW 4BQ. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1803 ..MOORE..07/27/25 ATTN...WFO...BYZ...BIS...UNR...ABR... STATUS REPORT FOR WS 546 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC011-025-270540- MT . MONTANA COUNTIES INCLUDED ARE CARTER FALLON NDC001-011-015-021-029-037-041-043-045-047-051-059-085-087-093- 270540- ND . NORTH DAKOTA COUNTIES INCLUDED ARE ADAMS BOWMAN BURLEIGH DICKEY EMMONS GRANT HETTINGER KIDDER LAMOURE LOGAN MCINTOSH MORTON SIOUX SLOPE STUTSMAN SDC019-021-031-041-045-049-063-075-089-093-105-107-115-117-119- 129-137-270540- Read more

WW 0546 Status Updates
STATUS REPORT ON WW 546 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 W PHP TO 30 WNW 4BQ. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1803 ..MOORE..07/27/25 ATTN...WFO...BYZ...BIS...UNR...ABR... STATUS REPORT FOR WS 546 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC011-025-270540- MT . MONTANA COUNTIES INCLUDED ARE CARTER FALLON NDC001-011-015-021-029-037-041-043-045-047-051-059-085-087-093- 270540- ND . NORTH DAKOTA COUNTIES INCLUDED ARE ADAMS BOWMAN BURLEIGH DICKEY EMMONS GRANT HETTINGER KIDDER LAMOURE LOGAN MCINTOSH MORTON SIOUX SLOPE STUTSMAN SDC019-021-031-041-045-049-063-075-089-093-105-107-115-117-119- 129-137-270540- Read more