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SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Mon Jul 28 2025 Valid 291200Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM MONTANA INTO THE CENTRAL HIGH PLAINS AND EASTWARD INTO PARTS OF THE MID-MISSISSIPPI VALLEY... ...SUMMARY... Severe thunderstorms are possible from southern Montana into the central High Plains as well as parts of the Mid-Missouri and Mid-Mississippi Valleys on Tuesday. ...Central Plains to Mid-MS Valley vicinity... The forecast for these areas is the most uncertain. Based on current guidance, it seems probable that much of Iowa/Minnesota will have been impacted by outflow from an MCS on Monday night. Consequently, there has been limited signal for development this far east during Tuesday afternoon. Marginal severe probabilities will be maintained for now. In southwestern Nebraska, a surface low is expected to develop. This surface low will likely be weaker than on Monday. With more limited mid-level ascent, low-level convergence, and warm temperatures aloft, it is not clear whether convection will form during the afternoon. Though not strong, there will be an increase in the low-level jet during the evening. This could lead to some development during early evening, but, again, there is very limited model support for this. The scenario with the most support is for convection to develop over the Laramie Range and eventually progress eastward. However, this development and eventual move off the terrain appears as though it will occur further into the evening. This is likely due to lingering inhibition in the Plains. For that reason, increasing wind probabilities will be withheld this outlook. ...Montana into the central High Plains... Confidence in storm initiation is highest within these locations. Moisture pushed up against the terrain will favors widely scattered to scattered convection by the afternoon. Effective shear will be around 40 kts. Storms will at least be briefly supercellular after initiation. However, with a drier boundary layer in place away from the terrain, storms will tend to become outflow dominant quickly. Furthermore, inhibition is expected to remain at lower elevations which may mean storms will only be severe for a brief period. Isolated large hail and severe wind gusts will be possible. ...Lower MI/IN/OH vicinity... Given the potential for a strong MCS and related MCV to develop on Monday night, there is some possibility for this activity to carry over into Tuesday morning/afternoon. Guidance continues to show the overnight convection dissipating. Shear will also become weaker as these remnant track south/east. However, with a very moist airmass in place across portions of these areas, trends in guidance will need to be monitored for a possible increase in severe probabilities. ..Wendt.. 07/28/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Mon Jul 28 2025 Valid 291200Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM MONTANA INTO THE CENTRAL HIGH PLAINS AND EASTWARD INTO PARTS OF THE MID-MISSISSIPPI VALLEY... ...SUMMARY... Severe thunderstorms are possible from southern Montana into the central High Plains as well as parts of the Mid-Missouri and Mid-Mississippi Valleys on Tuesday. ...Central Plains to Mid-MS Valley vicinity... The forecast for these areas is the most uncertain. Based on current guidance, it seems probable that much of Iowa/Minnesota will have been impacted by outflow from an MCS on Monday night. Consequently, there has been limited signal for development this far east during Tuesday afternoon. Marginal severe probabilities will be maintained for now. In southwestern Nebraska, a surface low is expected to develop. This surface low will likely be weaker than on Monday. With more limited mid-level ascent, low-level convergence, and warm temperatures aloft, it is not clear whether convection will form during the afternoon. Though not strong, there will be an increase in the low-level jet during the evening. This could lead to some development during early evening, but, again, there is very limited model support for this. The scenario with the most support is for convection to develop over the Laramie Range and eventually progress eastward. However, this development and eventual move off the terrain appears as though it will occur further into the evening. This is likely due to lingering inhibition in the Plains. For that reason, increasing wind probabilities will be withheld this outlook. ...Montana into the central High Plains... Confidence in storm initiation is highest within these locations. Moisture pushed up against the terrain will favors widely scattered to scattered convection by the afternoon. Effective shear will be around 40 kts. Storms will at least be briefly supercellular after initiation. However, with a drier boundary layer in place away from the terrain, storms will tend to become outflow dominant quickly. Furthermore, inhibition is expected to remain at lower elevations which may mean storms will only be severe for a brief period. Isolated large hail and severe wind gusts will be possible. ...Lower MI/IN/OH vicinity... Given the potential for a strong MCS and related MCV to develop on Monday night, there is some possibility for this activity to carry over into Tuesday morning/afternoon. Guidance continues to show the overnight convection dissipating. Shear will also become weaker as these remnant track south/east. However, with a very moist airmass in place across portions of these areas, trends in guidance will need to be monitored for a possible increase in severe probabilities. ..Wendt.. 07/28/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Mon Jul 28 2025 Valid 281200Z - 291200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF EASTERN SOUTH DAKOTA INTO FAR WESTERN MINNESOTA... ...SUMMARY... A derecho is likely across portions of the northern Plains, with several gusts expected to exceed 75 mph. A few line-embedded tornadoes and instances of severe hail may also occur. Isolated to potentially scattered storms may product severe wind and hail over portions of Montana. ...Synopsis... An upper ridge will dominate the upper-pattern across the CONUS today, with multiple mid-level perturbations poised to crest the upper ridge through the period. The first impulse is expected to trigger a cluster of thunderstorms that will rapidly grow upscale into an intense MCS and produce a widespread severe wind swath with embedded 75+ mph gusts across portions of the northern Plains. A second mid-level impulse will traverse the northern Rockies, amid favorable wind shear and buoyancy, to support a severe threat. ...Northern Plains... Multicellular convection is expected to initiate and grow upscale into an MCS across the northern High Plains at some point in the morning to early afternoon time frame. As the MCS propagates eastward across the Dakotas, and matures with a deepening cold pool, it will encounter an elongated corridor of extreme buoyancy, where mid 70s surface dewpoints beneath 9+ C/km mid-level lapse rates will boost MLCAPE to well over 5000 J/kg. Guidance consensus shows 50+ kts of effective bulk shear coinciding this extreme instability axis, with some hodographs depicting modest low-level size/curvature. This buoyancy/shear profile should support an intense MCS capable of producing a derecho, with widespread severe winds expected, and several 75+ mph gusts likely. Given anticipated strong low-level shear (e.g. 300+ m2/s2 effective SRH), a few tornadoes may occur with the stronger, more persistent leading-line system-scale mesovortices. Some CAM guidance differs slightly on the position of the derecho-producing MCS, including the possibility of a secondary bow echo developing closer to the SD/NE border. The track of the parent bow echo will be largely dependent on where the baroclinic boundary from an MCS (ongoing along the MN/IA border) sets up with daytime airmass modification. Therefore, some adjustments in the position of probabilities may be needed in future outlooks. Regardless of the aforementioned details, a higher-end severe wind event should unfold across the northern Plains, especially over central into eastern SD. ...Montana... Scattered thunderstorms will develop by afternoon peak heating in a post-frontal airmass. Despite a drier low-level airmass, 8-9 C/km troposheric lapse rates amid straight and elongated hodographs (effective bulk/speed shear near 50 kts) will support multicells and supercell structures capable of severe wind and hail. ..Squitieri/Dean.. 07/28/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Mon Jul 28 2025 Valid 281200Z - 291200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF EASTERN SOUTH DAKOTA INTO FAR WESTERN MINNESOTA... ...SUMMARY... A derecho is likely across portions of the northern Plains, with several gusts expected to exceed 75 mph. A few line-embedded tornadoes and instances of severe hail may also occur. Isolated to potentially scattered storms may product severe wind and hail over portions of Montana. ...Synopsis... An upper ridge will dominate the upper-pattern across the CONUS today, with multiple mid-level perturbations poised to crest the upper ridge through the period. The first impulse is expected to trigger a cluster of thunderstorms that will rapidly grow upscale into an intense MCS and produce a widespread severe wind swath with embedded 75+ mph gusts across portions of the northern Plains. A second mid-level impulse will traverse the northern Rockies, amid favorable wind shear and buoyancy, to support a severe threat. ...Northern Plains... Multicellular convection is expected to initiate and grow upscale into an MCS across the northern High Plains at some point in the morning to early afternoon time frame. As the MCS propagates eastward across the Dakotas, and matures with a deepening cold pool, it will encounter an elongated corridor of extreme buoyancy, where mid 70s surface dewpoints beneath 9+ C/km mid-level lapse rates will boost MLCAPE to well over 5000 J/kg. Guidance consensus shows 50+ kts of effective bulk shear coinciding this extreme instability axis, with some hodographs depicting modest low-level size/curvature. This buoyancy/shear profile should support an intense MCS capable of producing a derecho, with widespread severe winds expected, and several 75+ mph gusts likely. Given anticipated strong low-level shear (e.g. 300+ m2/s2 effective SRH), a few tornadoes may occur with the stronger, more persistent leading-line system-scale mesovortices. Some CAM guidance differs slightly on the position of the derecho-producing MCS, including the possibility of a secondary bow echo developing closer to the SD/NE border. The track of the parent bow echo will be largely dependent on where the baroclinic boundary from an MCS (ongoing along the MN/IA border) sets up with daytime airmass modification. Therefore, some adjustments in the position of probabilities may be needed in future outlooks. Regardless of the aforementioned details, a higher-end severe wind event should unfold across the northern Plains, especially over central into eastern SD. ...Montana... Scattered thunderstorms will develop by afternoon peak heating in a post-frontal airmass. Despite a drier low-level airmass, 8-9 C/km troposheric lapse rates amid straight and elongated hodographs (effective bulk/speed shear near 50 kts) will support multicells and supercell structures capable of severe wind and hail. ..Squitieri/Dean.. 07/28/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Mon Jul 28 2025 Valid 281200Z - 291200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF EASTERN SOUTH DAKOTA INTO FAR WESTERN MINNESOTA... ...SUMMARY... A derecho is likely across portions of the northern Plains, with several gusts expected to exceed 75 mph. A few line-embedded tornadoes and instances of severe hail may also occur. Isolated to potentially scattered storms may product severe wind and hail over portions of Montana. ...Synopsis... An upper ridge will dominate the upper-pattern across the CONUS today, with multiple mid-level perturbations poised to crest the upper ridge through the period. The first impulse is expected to trigger a cluster of thunderstorms that will rapidly grow upscale into an intense MCS and produce a widespread severe wind swath with embedded 75+ mph gusts across portions of the northern Plains. A second mid-level impulse will traverse the northern Rockies, amid favorable wind shear and buoyancy, to support a severe threat. ...Northern Plains... Multicellular convection is expected to initiate and grow upscale into an MCS across the northern High Plains at some point in the morning to early afternoon time frame. As the MCS propagates eastward across the Dakotas, and matures with a deepening cold pool, it will encounter an elongated corridor of extreme buoyancy, where mid 70s surface dewpoints beneath 9+ C/km mid-level lapse rates will boost MLCAPE to well over 5000 J/kg. Guidance consensus shows 50+ kts of effective bulk shear coinciding this extreme instability axis, with some hodographs depicting modest low-level size/curvature. This buoyancy/shear profile should support an intense MCS capable of producing a derecho, with widespread severe winds expected, and several 75+ mph gusts likely. Given anticipated strong low-level shear (e.g. 300+ m2/s2 effective SRH), a few tornadoes may occur with the stronger, more persistent leading-line system-scale mesovortices. Some CAM guidance differs slightly on the position of the derecho-producing MCS, including the possibility of a secondary bow echo developing closer to the SD/NE border. The track of the parent bow echo will be largely dependent on where the baroclinic boundary from an MCS (ongoing along the MN/IA border) sets up with daytime airmass modification. Therefore, some adjustments in the position of probabilities may be needed in future outlooks. Regardless of the aforementioned details, a higher-end severe wind event should unfold across the northern Plains, especially over central into eastern SD. ...Montana... Scattered thunderstorms will develop by afternoon peak heating in a post-frontal airmass. Despite a drier low-level airmass, 8-9 C/km troposheric lapse rates amid straight and elongated hodographs (effective bulk/speed shear near 50 kts) will support multicells and supercell structures capable of severe wind and hail. ..Squitieri/Dean.. 07/28/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Mon Jul 28 2025 Valid 281200Z - 291200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF EASTERN SOUTH DAKOTA INTO FAR WESTERN MINNESOTA... ...SUMMARY... A derecho is likely across portions of the northern Plains, with several gusts expected to exceed 75 mph. A few line-embedded tornadoes and instances of severe hail may also occur. Isolated to potentially scattered storms may product severe wind and hail over portions of Montana. ...Synopsis... An upper ridge will dominate the upper-pattern across the CONUS today, with multiple mid-level perturbations poised to crest the upper ridge through the period. The first impulse is expected to trigger a cluster of thunderstorms that will rapidly grow upscale into an intense MCS and produce a widespread severe wind swath with embedded 75+ mph gusts across portions of the northern Plains. A second mid-level impulse will traverse the northern Rockies, amid favorable wind shear and buoyancy, to support a severe threat. ...Northern Plains... Multicellular convection is expected to initiate and grow upscale into an MCS across the northern High Plains at some point in the morning to early afternoon time frame. As the MCS propagates eastward across the Dakotas, and matures with a deepening cold pool, it will encounter an elongated corridor of extreme buoyancy, where mid 70s surface dewpoints beneath 9+ C/km mid-level lapse rates will boost MLCAPE to well over 5000 J/kg. Guidance consensus shows 50+ kts of effective bulk shear coinciding this extreme instability axis, with some hodographs depicting modest low-level size/curvature. This buoyancy/shear profile should support an intense MCS capable of producing a derecho, with widespread severe winds expected, and several 75+ mph gusts likely. Given anticipated strong low-level shear (e.g. 300+ m2/s2 effective SRH), a few tornadoes may occur with the stronger, more persistent leading-line system-scale mesovortices. Some CAM guidance differs slightly on the position of the derecho-producing MCS, including the possibility of a secondary bow echo developing closer to the SD/NE border. The track of the parent bow echo will be largely dependent on where the baroclinic boundary from an MCS (ongoing along the MN/IA border) sets up with daytime airmass modification. Therefore, some adjustments in the position of probabilities may be needed in future outlooks. Regardless of the aforementioned details, a higher-end severe wind event should unfold across the northern Plains, especially over central into eastern SD. ...Montana... Scattered thunderstorms will develop by afternoon peak heating in a post-frontal airmass. Despite a drier low-level airmass, 8-9 C/km troposheric lapse rates amid straight and elongated hodographs (effective bulk/speed shear near 50 kts) will support multicells and supercell structures capable of severe wind and hail. ..Squitieri/Dean.. 07/28/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Mon Jul 28 2025 Valid 281200Z - 291200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF EASTERN SOUTH DAKOTA INTO FAR WESTERN MINNESOTA... ...SUMMARY... A derecho is likely across portions of the northern Plains, with several gusts expected to exceed 75 mph. A few line-embedded tornadoes and instances of severe hail may also occur. Isolated to potentially scattered storms may product severe wind and hail over portions of Montana. ...Synopsis... An upper ridge will dominate the upper-pattern across the CONUS today, with multiple mid-level perturbations poised to crest the upper ridge through the period. The first impulse is expected to trigger a cluster of thunderstorms that will rapidly grow upscale into an intense MCS and produce a widespread severe wind swath with embedded 75+ mph gusts across portions of the northern Plains. A second mid-level impulse will traverse the northern Rockies, amid favorable wind shear and buoyancy, to support a severe threat. ...Northern Plains... Multicellular convection is expected to initiate and grow upscale into an MCS across the northern High Plains at some point in the morning to early afternoon time frame. As the MCS propagates eastward across the Dakotas, and matures with a deepening cold pool, it will encounter an elongated corridor of extreme buoyancy, where mid 70s surface dewpoints beneath 9+ C/km mid-level lapse rates will boost MLCAPE to well over 5000 J/kg. Guidance consensus shows 50+ kts of effective bulk shear coinciding this extreme instability axis, with some hodographs depicting modest low-level size/curvature. This buoyancy/shear profile should support an intense MCS capable of producing a derecho, with widespread severe winds expected, and several 75+ mph gusts likely. Given anticipated strong low-level shear (e.g. 300+ m2/s2 effective SRH), a few tornadoes may occur with the stronger, more persistent leading-line system-scale mesovortices. Some CAM guidance differs slightly on the position of the derecho-producing MCS, including the possibility of a secondary bow echo developing closer to the SD/NE border. The track of the parent bow echo will be largely dependent on where the baroclinic boundary from an MCS (ongoing along the MN/IA border) sets up with daytime airmass modification. Therefore, some adjustments in the position of probabilities may be needed in future outlooks. Regardless of the aforementioned details, a higher-end severe wind event should unfold across the northern Plains, especially over central into eastern SD. ...Montana... Scattered thunderstorms will develop by afternoon peak heating in a post-frontal airmass. Despite a drier low-level airmass, 8-9 C/km troposheric lapse rates amid straight and elongated hodographs (effective bulk/speed shear near 50 kts) will support multicells and supercell structures capable of severe wind and hail. ..Squitieri/Dean.. 07/28/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Mon Jul 28 2025 Valid 281200Z - 291200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF EASTERN SOUTH DAKOTA INTO FAR WESTERN MINNESOTA... ...SUMMARY... A derecho is likely across portions of the northern Plains, with several gusts expected to exceed 75 mph. A few line-embedded tornadoes and instances of severe hail may also occur. Isolated to potentially scattered storms may product severe wind and hail over portions of Montana. ...Synopsis... An upper ridge will dominate the upper-pattern across the CONUS today, with multiple mid-level perturbations poised to crest the upper ridge through the period. The first impulse is expected to trigger a cluster of thunderstorms that will rapidly grow upscale into an intense MCS and produce a widespread severe wind swath with embedded 75+ mph gusts across portions of the northern Plains. A second mid-level impulse will traverse the northern Rockies, amid favorable wind shear and buoyancy, to support a severe threat. ...Northern Plains... Multicellular convection is expected to initiate and grow upscale into an MCS across the northern High Plains at some point in the morning to early afternoon time frame. As the MCS propagates eastward across the Dakotas, and matures with a deepening cold pool, it will encounter an elongated corridor of extreme buoyancy, where mid 70s surface dewpoints beneath 9+ C/km mid-level lapse rates will boost MLCAPE to well over 5000 J/kg. Guidance consensus shows 50+ kts of effective bulk shear coinciding this extreme instability axis, with some hodographs depicting modest low-level size/curvature. This buoyancy/shear profile should support an intense MCS capable of producing a derecho, with widespread severe winds expected, and several 75+ mph gusts likely. Given anticipated strong low-level shear (e.g. 300+ m2/s2 effective SRH), a few tornadoes may occur with the stronger, more persistent leading-line system-scale mesovortices. Some CAM guidance differs slightly on the position of the derecho-producing MCS, including the possibility of a secondary bow echo developing closer to the SD/NE border. The track of the parent bow echo will be largely dependent on where the baroclinic boundary from an MCS (ongoing along the MN/IA border) sets up with daytime airmass modification. Therefore, some adjustments in the position of probabilities may be needed in future outlooks. Regardless of the aforementioned details, a higher-end severe wind event should unfold across the northern Plains, especially over central into eastern SD. ...Montana... Scattered thunderstorms will develop by afternoon peak heating in a post-frontal airmass. Despite a drier low-level airmass, 8-9 C/km troposheric lapse rates amid straight and elongated hodographs (effective bulk/speed shear near 50 kts) will support multicells and supercell structures capable of severe wind and hail. ..Squitieri/Dean.. 07/28/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Mon Jul 28 2025 Valid 281200Z - 291200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF EASTERN SOUTH DAKOTA INTO FAR WESTERN MINNESOTA... ...SUMMARY... A derecho is likely across portions of the northern Plains, with several gusts expected to exceed 75 mph. A few line-embedded tornadoes and instances of severe hail may also occur. Isolated to potentially scattered storms may product severe wind and hail over portions of Montana. ...Synopsis... An upper ridge will dominate the upper-pattern across the CONUS today, with multiple mid-level perturbations poised to crest the upper ridge through the period. The first impulse is expected to trigger a cluster of thunderstorms that will rapidly grow upscale into an intense MCS and produce a widespread severe wind swath with embedded 75+ mph gusts across portions of the northern Plains. A second mid-level impulse will traverse the northern Rockies, amid favorable wind shear and buoyancy, to support a severe threat. ...Northern Plains... Multicellular convection is expected to initiate and grow upscale into an MCS across the northern High Plains at some point in the morning to early afternoon time frame. As the MCS propagates eastward across the Dakotas, and matures with a deepening cold pool, it will encounter an elongated corridor of extreme buoyancy, where mid 70s surface dewpoints beneath 9+ C/km mid-level lapse rates will boost MLCAPE to well over 5000 J/kg. Guidance consensus shows 50+ kts of effective bulk shear coinciding this extreme instability axis, with some hodographs depicting modest low-level size/curvature. This buoyancy/shear profile should support an intense MCS capable of producing a derecho, with widespread severe winds expected, and several 75+ mph gusts likely. Given anticipated strong low-level shear (e.g. 300+ m2/s2 effective SRH), a few tornadoes may occur with the stronger, more persistent leading-line system-scale mesovortices. Some CAM guidance differs slightly on the position of the derecho-producing MCS, including the possibility of a secondary bow echo developing closer to the SD/NE border. The track of the parent bow echo will be largely dependent on where the baroclinic boundary from an MCS (ongoing along the MN/IA border) sets up with daytime airmass modification. Therefore, some adjustments in the position of probabilities may be needed in future outlooks. Regardless of the aforementioned details, a higher-end severe wind event should unfold across the northern Plains, especially over central into eastern SD. ...Montana... Scattered thunderstorms will develop by afternoon peak heating in a post-frontal airmass. Despite a drier low-level airmass, 8-9 C/km troposheric lapse rates amid straight and elongated hodographs (effective bulk/speed shear near 50 kts) will support multicells and supercell structures capable of severe wind and hail. ..Squitieri/Dean.. 07/28/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Mon Jul 28 2025 Valid 281200Z - 291200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF EASTERN SOUTH DAKOTA INTO FAR WESTERN MINNESOTA... ...SUMMARY... A derecho is likely across portions of the northern Plains, with several gusts expected to exceed 75 mph. A few line-embedded tornadoes and instances of severe hail may also occur. Isolated to potentially scattered storms may product severe wind and hail over portions of Montana. ...Synopsis... An upper ridge will dominate the upper-pattern across the CONUS today, with multiple mid-level perturbations poised to crest the upper ridge through the period. The first impulse is expected to trigger a cluster of thunderstorms that will rapidly grow upscale into an intense MCS and produce a widespread severe wind swath with embedded 75+ mph gusts across portions of the northern Plains. A second mid-level impulse will traverse the northern Rockies, amid favorable wind shear and buoyancy, to support a severe threat. ...Northern Plains... Multicellular convection is expected to initiate and grow upscale into an MCS across the northern High Plains at some point in the morning to early afternoon time frame. As the MCS propagates eastward across the Dakotas, and matures with a deepening cold pool, it will encounter an elongated corridor of extreme buoyancy, where mid 70s surface dewpoints beneath 9+ C/km mid-level lapse rates will boost MLCAPE to well over 5000 J/kg. Guidance consensus shows 50+ kts of effective bulk shear coinciding this extreme instability axis, with some hodographs depicting modest low-level size/curvature. This buoyancy/shear profile should support an intense MCS capable of producing a derecho, with widespread severe winds expected, and several 75+ mph gusts likely. Given anticipated strong low-level shear (e.g. 300+ m2/s2 effective SRH), a few tornadoes may occur with the stronger, more persistent leading-line system-scale mesovortices. Some CAM guidance differs slightly on the position of the derecho-producing MCS, including the possibility of a secondary bow echo developing closer to the SD/NE border. The track of the parent bow echo will be largely dependent on where the baroclinic boundary from an MCS (ongoing along the MN/IA border) sets up with daytime airmass modification. Therefore, some adjustments in the position of probabilities may be needed in future outlooks. Regardless of the aforementioned details, a higher-end severe wind event should unfold across the northern Plains, especially over central into eastern SD. ...Montana... Scattered thunderstorms will develop by afternoon peak heating in a post-frontal airmass. Despite a drier low-level airmass, 8-9 C/km troposheric lapse rates amid straight and elongated hodographs (effective bulk/speed shear near 50 kts) will support multicells and supercell structures capable of severe wind and hail. ..Squitieri/Dean.. 07/28/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Mon Jul 28 2025 Valid 281200Z - 291200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF EASTERN SOUTH DAKOTA INTO FAR WESTERN MINNESOTA... ...SUMMARY... A derecho is likely across portions of the northern Plains, with several gusts expected to exceed 75 mph. A few line-embedded tornadoes and instances of severe hail may also occur. Isolated to potentially scattered storms may product severe wind and hail over portions of Montana. ...Synopsis... An upper ridge will dominate the upper-pattern across the CONUS today, with multiple mid-level perturbations poised to crest the upper ridge through the period. The first impulse is expected to trigger a cluster of thunderstorms that will rapidly grow upscale into an intense MCS and produce a widespread severe wind swath with embedded 75+ mph gusts across portions of the northern Plains. A second mid-level impulse will traverse the northern Rockies, amid favorable wind shear and buoyancy, to support a severe threat. ...Northern Plains... Multicellular convection is expected to initiate and grow upscale into an MCS across the northern High Plains at some point in the morning to early afternoon time frame. As the MCS propagates eastward across the Dakotas, and matures with a deepening cold pool, it will encounter an elongated corridor of extreme buoyancy, where mid 70s surface dewpoints beneath 9+ C/km mid-level lapse rates will boost MLCAPE to well over 5000 J/kg. Guidance consensus shows 50+ kts of effective bulk shear coinciding this extreme instability axis, with some hodographs depicting modest low-level size/curvature. This buoyancy/shear profile should support an intense MCS capable of producing a derecho, with widespread severe winds expected, and several 75+ mph gusts likely. Given anticipated strong low-level shear (e.g. 300+ m2/s2 effective SRH), a few tornadoes may occur with the stronger, more persistent leading-line system-scale mesovortices. Some CAM guidance differs slightly on the position of the derecho-producing MCS, including the possibility of a secondary bow echo developing closer to the SD/NE border. The track of the parent bow echo will be largely dependent on where the baroclinic boundary from an MCS (ongoing along the MN/IA border) sets up with daytime airmass modification. Therefore, some adjustments in the position of probabilities may be needed in future outlooks. Regardless of the aforementioned details, a higher-end severe wind event should unfold across the northern Plains, especially over central into eastern SD. ...Montana... Scattered thunderstorms will develop by afternoon peak heating in a post-frontal airmass. Despite a drier low-level airmass, 8-9 C/km troposheric lapse rates amid straight and elongated hodographs (effective bulk/speed shear near 50 kts) will support multicells and supercell structures capable of severe wind and hail. ..Squitieri/Dean.. 07/28/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Mon Jul 28 2025 Valid 281200Z - 291200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF EASTERN SOUTH DAKOTA INTO FAR WESTERN MINNESOTA... ...SUMMARY... A derecho is likely across portions of the northern Plains, with several gusts expected to exceed 75 mph. A few line-embedded tornadoes and instances of severe hail may also occur. Isolated to potentially scattered storms may product severe wind and hail over portions of Montana. ...Synopsis... An upper ridge will dominate the upper-pattern across the CONUS today, with multiple mid-level perturbations poised to crest the upper ridge through the period. The first impulse is expected to trigger a cluster of thunderstorms that will rapidly grow upscale into an intense MCS and produce a widespread severe wind swath with embedded 75+ mph gusts across portions of the northern Plains. A second mid-level impulse will traverse the northern Rockies, amid favorable wind shear and buoyancy, to support a severe threat. ...Northern Plains... Multicellular convection is expected to initiate and grow upscale into an MCS across the northern High Plains at some point in the morning to early afternoon time frame. As the MCS propagates eastward across the Dakotas, and matures with a deepening cold pool, it will encounter an elongated corridor of extreme buoyancy, where mid 70s surface dewpoints beneath 9+ C/km mid-level lapse rates will boost MLCAPE to well over 5000 J/kg. Guidance consensus shows 50+ kts of effective bulk shear coinciding this extreme instability axis, with some hodographs depicting modest low-level size/curvature. This buoyancy/shear profile should support an intense MCS capable of producing a derecho, with widespread severe winds expected, and several 75+ mph gusts likely. Given anticipated strong low-level shear (e.g. 300+ m2/s2 effective SRH), a few tornadoes may occur with the stronger, more persistent leading-line system-scale mesovortices. Some CAM guidance differs slightly on the position of the derecho-producing MCS, including the possibility of a secondary bow echo developing closer to the SD/NE border. The track of the parent bow echo will be largely dependent on where the baroclinic boundary from an MCS (ongoing along the MN/IA border) sets up with daytime airmass modification. Therefore, some adjustments in the position of probabilities may be needed in future outlooks. Regardless of the aforementioned details, a higher-end severe wind event should unfold across the northern Plains, especially over central into eastern SD. ...Montana... Scattered thunderstorms will develop by afternoon peak heating in a post-frontal airmass. Despite a drier low-level airmass, 8-9 C/km troposheric lapse rates amid straight and elongated hodographs (effective bulk/speed shear near 50 kts) will support multicells and supercell structures capable of severe wind and hail. ..Squitieri/Dean.. 07/28/2025 Read more

915
ABPZ20 KNHC 280513
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 PM PDT Sun Jul 27 2025

For the eastern and central North Pacific east of 180 longitude:

Active Systems:
The National Hurricane Center is issuing advisories on Tropical
Storm Iona, located in the central Pacific basin well southeast of
the Hawaiian Islands.

Western East Pacific:
An area of low pressure well east-southeast of the Hawaiian Islands
is producing disorganized showers and thunderstorms. Gradual
development of this system is possible and a tropical depression
could form during the next couple of days as it moves generally
westward around 10 mph.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 7 days...medium...40 percent.

South of Southwestern Mexico:
A disturbance located several hundred miles south-southwest of the
Gulf of Tehuantepec is producing a large area of disorganized
showers and thunderstorms. During the next day or two, an area of
low pressure is forecast to form from this area of disturbed
weather, well off the coast of southwestern Mexico. Thereafter,
environmental conditions appear conducive for gradual development of
this system, and a tropical depression is likely to form late this
week as it moves west-northwestward or northwestward at 10 to 15
mph.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...high...70 percent.

&&

Public advisories on Tropical Storm Iona are issued under WMO header
WTPA31 PHFO and under AWIPS header HFOTCPCP1.
Forecast/Advisories on Tropical Storm Iona are issued under WMO
header WTPA21 PHFO and under AWIPS header HFOTCMCP1.

$$
Forecaster Jelsema

000
ABNT20 KNHC 280501
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Mon Jul 28 2025

For the North Atlantic...Caribbean Sea and the Gulf of America:

Tropical cyclone formation is not expected during the next 7 days.

$$
Forecaster Jelsema

WW 0548 Status Updates
STATUS REPORT ON WW 548 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 NE HON TO 25 SE ATY TO 15 WSW RWF TO 25 W MKT TO 10 WSW MKT TO 25 ESE MKT TO 20 WNW RST. ..BROYLES..07/28/25 ATTN...WFO...MPX...ABR...FSD... STATUS REPORT FOR WS 548 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC013-033-043-047-063-081-083-091-101-105-117-127-133-147-161- 165-280540- MN . MINNESOTA COUNTIES INCLUDED ARE BLUE EARTH COTTONWOOD FARIBAULT FREEBORN JACKSON LINCOLN LYON MARTIN MURRAY NOBLES PIPESTONE REDWOOD ROCK STEELE WASECA WATONWAN SDC003-005-011-015-023-035-043-053-061-073-077-079-087-097-099- 101-111-280540- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE AURORA BEADLE BROOKINGS BRULE CHARLES MIX DAVISON DOUGLAS GREGORY HANSON JERAULD KINGSBURY LAKE Read more

WW 0548 Status Updates
STATUS REPORT ON WW 548 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 NE HON TO 25 SE ATY TO 15 WSW RWF TO 25 W MKT TO 10 WSW MKT TO 25 ESE MKT TO 20 WNW RST. ..BROYLES..07/28/25 ATTN...WFO...MPX...ABR...FSD... STATUS REPORT FOR WS 548 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC013-033-043-047-063-081-083-091-101-105-117-127-133-147-161- 165-280540- MN . MINNESOTA COUNTIES INCLUDED ARE BLUE EARTH COTTONWOOD FARIBAULT FREEBORN JACKSON LINCOLN LYON MARTIN MURRAY NOBLES PIPESTONE REDWOOD ROCK STEELE WASECA WATONWAN SDC003-005-011-015-023-035-043-053-061-073-077-079-087-097-099- 101-111-280540- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE AURORA BEADLE BROOKINGS BRULE CHARLES MIX DAVISON DOUGLAS GREGORY HANSON JERAULD KINGSBURY LAKE Read more

WW 548 SEVERE TSTM MN SD 272145Z - 280500Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 548 NWS Storm Prediction Center Norman OK 445 PM CDT Sun Jul 27 2025 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Central and Southern Minnesota Eastern South Dakota * Effective this Sunday afternoon from 445 PM until Midnight CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph likely Scattered large hail and isolated very large hail events to 2 inches in diameter possible A tornado or two possible SUMMARY...Strong to severe thunderstorms are ongoing across west-central MN and adjacent far northeastern SD. These storms developed in a strongly unstable and sheared environment and are expected to persist through the afternoon. Additional severe storm development is possible across eastern SD as well. Large to very large hail and strong gusts are possible with these storms. A brief tornado could also occur. Over time, the development of a southward-moving convective line is possible, with the threat for strong to severe gusts continuing within this line. The severe thunderstorm watch area is approximately along and 60 statute miles north and south of a line from 50 miles southwest of Watertown SD to 30 miles north northeast of Minneapolis MN. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU8). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 28030. ...Mosier Read more

MD 1818 CONCERNING SEVERE THUNDERSTORM WATCH 548... FOR FAR SOUTHERN MINNESOTA...FAR SOUTHEAST SOUTH DAKOTA...FAR NORTHERN IOWA
Mesoscale Discussion 1818 NWS Storm Prediction Center Norman OK 0947 PM CDT Sun Jul 27 2025 Areas affected...Far Southern Minnesota...Far Southeast South Dakota...Far Northern Iowa Concerning...Severe Thunderstorm Watch 548... Valid 280247Z - 280445Z The severe weather threat for Severe Thunderstorm Watch 548 continues. SUMMARY...An isolated severe threat is expected to continue into far southern Minnesota, far southeast South Dakota and northern Iowa over the next few hours. Wind damage and hail will be the primary threats. DISCUSSION...A broken line of strong to severe thunderstorms is currently ongoing from northeast South Dakota eastward across southern Minnesota. Additional storms are ongoing near a surface low in southeast South Dakota. To the east of the surface low, a moist and unstable airmass is in place, with the RAP showing MLCAPE ranging from near 5500 J/kg in southeast South Dakota to around 2500 J/kg in northeast Iowa. The instability, along with large-scale ascent associated with the right entrance region of the upper-level jet, is supporting continued convective development this evening. In addition, the latest WSR-88D VWP at Sioux Falls, South Dakota has 40 knots of 0-6 km shear, and the RAP suggests this is representative for much of the airmass to the south of the ongoing convection. This will support threat for wind damage and hail with the more intense parts of the line over the next couple hours, mainly over southeast South Dakota and southwest Minnesota were the strongest instability is present. As the convection moves southward, a gradual downtrend in the severe threat is expected due to less favorable storm modes, especially over parts of north-central and northeast Iowa where the RAP shows a less supportive shear environment. ..Broyles.. 07/28/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DVN...ARX...MPX...DMX...FSD...OAX... LAT...LON 43029806 43589819 43989806 44379768 44449717 44269613 44159546 44109396 44319292 44209199 43849141 43439125 43059133 42699166 42499246 42489299 42499466 42589671 42779756 43029806 MOST PROBABLE PEAK TORNADO INTENSITY...85-115 MPH MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

WW 0548 Status Updates
STATUS REPORT ON WW 548 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 WSW ABR TO 40 S VVV TO 15 NW RWF TO 35 W MSP TO 45 NE MSP. ..BROYLES..07/28/25 ATTN...WFO...MPX...ABR...FSD... STATUS REPORT FOR WS 548 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC013-015-033-037-043-047-049-063-079-081-083-091-101-103-105- 117-127-129-131-133-139-143-147-161-163-165-173-280440- MN . MINNESOTA COUNTIES INCLUDED ARE BLUE EARTH BROWN COTTONWOOD DAKOTA FARIBAULT FREEBORN GOODHUE JACKSON LE SUEUR LINCOLN LYON MARTIN MURRAY NICOLLET NOBLES PIPESTONE REDWOOD RENVILLE RICE ROCK SCOTT SIBLEY STEELE WASECA WASHINGTON WATONWAN YELLOW MEDICINE SDC003-005-011-015-023-025-035-039-043-053-057-061-073-077-079- 087-097-099-101-111-115-280440- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE AURORA BEADLE BROOKINGS BRULE CHARLES MIX CLARK Read more

MD 1817 CONCERNING SEVERE THUNDERSTORM WATCH 548... FOR FAR EASTERN SOUTH DAKOTA...SOUTH-CENTRAL MINNESOTA
Mesoscale Discussion 1817 NWS Storm Prediction Center Norman OK 0719 PM CDT Sun Jul 27 2025 Areas affected...Far Eastern South Dakota...South-central Minnesota Concerning...Severe Thunderstorm Watch 548... Valid 280019Z - 280215Z The severe weather threat for Severe Thunderstorm Watch 548 continues. SUMMARY...The severe threat, associated with a convective complex from eastern South Dakota into south-central Minnesota, is expected to gradually shift eastward and southward across southern Minnesota over the next few hours. Although a brief tornado will be possible, large hail and wind damage are expected to be the primary threats. A new weather watch may need to be considered to the east of the current watch. DISCUSSION...Mosaic radar imagery currently shows an east-to-west cluster of strong to severe storms from near Watertown, South Dakota eastward to just west of Minneapolis, Minnesota. This relatively large cluster is located along a strong gradient of instability, which extends southeastward into northern Iowa. These storms are forecast to develop southeastward along this gradient over the next few hours. The eastern edge of the complex may also affect parts of far southeastern Minnesota and far western Wisconsin. Moderate to strong instability, along with 0-6 km in the 30 to 45 knot range according to the RAP and 00Z Minneapolis sounding, should support a continued severe threat. Supercells with isolated large hail will be possible. Wind damage will be likely within and near the faster moving bowing line segments. ..Broyles/Mosier.. 07/28/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ARX...MPX...FSD...ABR... LAT...LON 45739592 45399306 45009191 44339170 43749205 43559271 43579393 43589436 43609563 43639698 44049749 44409753 44869745 45299711 45579660 45739592 MOST PROBABLE PEAK TORNADO INTENSITY...85-115 MPH MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN Read more