Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1053 AM CDT Tue Aug 05 2025 Valid 051700Z - 061200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE EASTERN GREAT BASIN TO THE FOUR CORNERS... The previous forecast (see below) remains on track. ..Squitieri.. 08/05/2025 .PREV DISCUSSION... /ISSUED 0200 AM CDT Tue Aug 05 2025/ ...Synopsis... An expansive midlevel anticyclone will build over the Southwest, while broad midlevel troughing persists across much of the Intermountain West/Great Basin. Between these two features, enhanced deep-layer west-southwesterly flow will be maintained across the Great Basin into the northern/central Rockies. ...Great Basin into the central Rockies... Diurnal heating amid a warm/dry antecedent air mass will lead to another day of widespread single-digit to lower teens RH. At the same time, deep boundary-layer mixing into the enhanced flow aloft will favor breezy/gusty west-southwesterly surface winds area-wide. Across southern/central UT, far northern AZ, and northwest CO, the overlap of 20-25 mph sustained surface winds and single-digit RH will result in critical fire-weather conditions, given highly receptive fuels and several ongoing wildfires across the region. ...Dry Thunderstorms - Southwest... The 00Z TUS observed sounding sampled increasing midlevel moisture that is being drawn northward along the western periphery of the expansive midlevel anticyclone. Along the northern edge of the deeper moisture plume, inverted-V soundings and 0.60-0.75 inch PW will promote isolated dry thunderstorms across parts of eastern AZ and western NM during the afternoon. These storms will pose a risk of strong/erratic outflow winds and lightning-induced ignitions over dry fuels. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Tue Aug 05 2025 Valid 051300Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF NORTH AND SOUTH DAKOTA... ...SUMMARY... Thunderstorms associated with a threat for severe gusts and large hail will be possible across parts of the Dakotas today into this evening. ...Northern Plains... Warm-air advection showers and thunderstorms are ongoing this morning across the western Dakotas, where the western edge of the low-level jet overlaps the eastern edge of the steep mid-level lapse rates. These storms will likely continue northeastward this morning, perhaps even expanding in coverage, as the low-level jet persists and large-scale ascent attendant to an approaching shortwave trough strengthens. Occasionally strong updrafts could produce hail and a damaging gust or two. Cloud cover and outflow associated with these storms could result in an effective warm front extending from a weak low over western SD eastward across central and eastern SD. The exact location and sharpness of this front remain uncertain. Given that the shortwave trough will likely remain well west of the region, low-level convergence near this boundary as well as the surface low should both be areas where convective initiation is most likely this afternoon. Ample buoyancy and vertical shear will be in place for supercells with the initial development, with large hail and damaging gusts as the primary risks. Stronger low to mid-level flow may be in place across eastern SD, contributing to greater low-level shear and relatively higher tornado potential. Primary concern across eastern SD is whether or not the warmer low to mid-level temperatures inhibit the development of mature updrafts. One other scenario that seems plausible is for storms on southern periphery the ongoing cluster to become increasingly surface based as they move eastward/northeastward with time. Given current trends and recent guidance, this would most likely occur along the eastern ND/SD border after 20Z. As previously mentioned, hail is possible within this cluster throughout the day, but the transition to a more surface-based character could introduce the threat for stronger gusts as well. A strengthening low-level jet coupled with persistent mid-level westerlies support the potential for upscale growth in a east-southeastward progressing MCS. Damaging gusts will be possible with this MCS, particularly over SD, but increasing low-level stability should result in a gradually diminishing severe potential with eastward/southeastward extend into northeast NE, northwest IA, and southwest MN. ..Mosier/Bentley.. 08/05/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Tue Aug 05 2025 Valid 051300Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF NORTH AND SOUTH DAKOTA... ...SUMMARY... Thunderstorms associated with a threat for severe gusts and large hail will be possible across parts of the Dakotas today into this evening. ...Northern Plains... Warm-air advection showers and thunderstorms are ongoing this morning across the western Dakotas, where the western edge of the low-level jet overlaps the eastern edge of the steep mid-level lapse rates. These storms will likely continue northeastward this morning, perhaps even expanding in coverage, as the low-level jet persists and large-scale ascent attendant to an approaching shortwave trough strengthens. Occasionally strong updrafts could produce hail and a damaging gust or two. Cloud cover and outflow associated with these storms could result in an effective warm front extending from a weak low over western SD eastward across central and eastern SD. The exact location and sharpness of this front remain uncertain. Given that the shortwave trough will likely remain well west of the region, low-level convergence near this boundary as well as the surface low should both be areas where convective initiation is most likely this afternoon. Ample buoyancy and vertical shear will be in place for supercells with the initial development, with large hail and damaging gusts as the primary risks. Stronger low to mid-level flow may be in place across eastern SD, contributing to greater low-level shear and relatively higher tornado potential. Primary concern across eastern SD is whether or not the warmer low to mid-level temperatures inhibit the development of mature updrafts. One other scenario that seems plausible is for storms on southern periphery the ongoing cluster to become increasingly surface based as they move eastward/northeastward with time. Given current trends and recent guidance, this would most likely occur along the eastern ND/SD border after 20Z. As previously mentioned, hail is possible within this cluster throughout the day, but the transition to a more surface-based character could introduce the threat for stronger gusts as well. A strengthening low-level jet coupled with persistent mid-level westerlies support the potential for upscale growth in a east-southeastward progressing MCS. Damaging gusts will be possible with this MCS, particularly over SD, but increasing low-level stability should result in a gradually diminishing severe potential with eastward/southeastward extend into northeast NE, northwest IA, and southwest MN. ..Mosier/Bentley.. 08/05/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Tue Aug 05 2025 Valid 051300Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF NORTH AND SOUTH DAKOTA... ...SUMMARY... Thunderstorms associated with a threat for severe gusts and large hail will be possible across parts of the Dakotas today into this evening. ...Northern Plains... Warm-air advection showers and thunderstorms are ongoing this morning across the western Dakotas, where the western edge of the low-level jet overlaps the eastern edge of the steep mid-level lapse rates. These storms will likely continue northeastward this morning, perhaps even expanding in coverage, as the low-level jet persists and large-scale ascent attendant to an approaching shortwave trough strengthens. Occasionally strong updrafts could produce hail and a damaging gust or two. Cloud cover and outflow associated with these storms could result in an effective warm front extending from a weak low over western SD eastward across central and eastern SD. The exact location and sharpness of this front remain uncertain. Given that the shortwave trough will likely remain well west of the region, low-level convergence near this boundary as well as the surface low should both be areas where convective initiation is most likely this afternoon. Ample buoyancy and vertical shear will be in place for supercells with the initial development, with large hail and damaging gusts as the primary risks. Stronger low to mid-level flow may be in place across eastern SD, contributing to greater low-level shear and relatively higher tornado potential. Primary concern across eastern SD is whether or not the warmer low to mid-level temperatures inhibit the development of mature updrafts. One other scenario that seems plausible is for storms on southern periphery the ongoing cluster to become increasingly surface based as they move eastward/northeastward with time. Given current trends and recent guidance, this would most likely occur along the eastern ND/SD border after 20Z. As previously mentioned, hail is possible within this cluster throughout the day, but the transition to a more surface-based character could introduce the threat for stronger gusts as well. A strengthening low-level jet coupled with persistent mid-level westerlies support the potential for upscale growth in a east-southeastward progressing MCS. Damaging gusts will be possible with this MCS, particularly over SD, but increasing low-level stability should result in a gradually diminishing severe potential with eastward/southeastward extend into northeast NE, northwest IA, and southwest MN. ..Mosier/Bentley.. 08/05/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Tue Aug 05 2025 Valid 051300Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF NORTH AND SOUTH DAKOTA... ...SUMMARY... Thunderstorms associated with a threat for severe gusts and large hail will be possible across parts of the Dakotas today into this evening. ...Northern Plains... Warm-air advection showers and thunderstorms are ongoing this morning across the western Dakotas, where the western edge of the low-level jet overlaps the eastern edge of the steep mid-level lapse rates. These storms will likely continue northeastward this morning, perhaps even expanding in coverage, as the low-level jet persists and large-scale ascent attendant to an approaching shortwave trough strengthens. Occasionally strong updrafts could produce hail and a damaging gust or two. Cloud cover and outflow associated with these storms could result in an effective warm front extending from a weak low over western SD eastward across central and eastern SD. The exact location and sharpness of this front remain uncertain. Given that the shortwave trough will likely remain well west of the region, low-level convergence near this boundary as well as the surface low should both be areas where convective initiation is most likely this afternoon. Ample buoyancy and vertical shear will be in place for supercells with the initial development, with large hail and damaging gusts as the primary risks. Stronger low to mid-level flow may be in place across eastern SD, contributing to greater low-level shear and relatively higher tornado potential. Primary concern across eastern SD is whether or not the warmer low to mid-level temperatures inhibit the development of mature updrafts. One other scenario that seems plausible is for storms on southern periphery the ongoing cluster to become increasingly surface based as they move eastward/northeastward with time. Given current trends and recent guidance, this would most likely occur along the eastern ND/SD border after 20Z. As previously mentioned, hail is possible within this cluster throughout the day, but the transition to a more surface-based character could introduce the threat for stronger gusts as well. A strengthening low-level jet coupled with persistent mid-level westerlies support the potential for upscale growth in a east-southeastward progressing MCS. Damaging gusts will be possible with this MCS, particularly over SD, but increasing low-level stability should result in a gradually diminishing severe potential with eastward/southeastward extend into northeast NE, northwest IA, and southwest MN. ..Mosier/Bentley.. 08/05/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Tue Aug 05 2025 Valid 051300Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF NORTH AND SOUTH DAKOTA... ...SUMMARY... Thunderstorms associated with a threat for severe gusts and large hail will be possible across parts of the Dakotas today into this evening. ...Northern Plains... Warm-air advection showers and thunderstorms are ongoing this morning across the western Dakotas, where the western edge of the low-level jet overlaps the eastern edge of the steep mid-level lapse rates. These storms will likely continue northeastward this morning, perhaps even expanding in coverage, as the low-level jet persists and large-scale ascent attendant to an approaching shortwave trough strengthens. Occasionally strong updrafts could produce hail and a damaging gust or two. Cloud cover and outflow associated with these storms could result in an effective warm front extending from a weak low over western SD eastward across central and eastern SD. The exact location and sharpness of this front remain uncertain. Given that the shortwave trough will likely remain well west of the region, low-level convergence near this boundary as well as the surface low should both be areas where convective initiation is most likely this afternoon. Ample buoyancy and vertical shear will be in place for supercells with the initial development, with large hail and damaging gusts as the primary risks. Stronger low to mid-level flow may be in place across eastern SD, contributing to greater low-level shear and relatively higher tornado potential. Primary concern across eastern SD is whether or not the warmer low to mid-level temperatures inhibit the development of mature updrafts. One other scenario that seems plausible is for storms on southern periphery the ongoing cluster to become increasingly surface based as they move eastward/northeastward with time. Given current trends and recent guidance, this would most likely occur along the eastern ND/SD border after 20Z. As previously mentioned, hail is possible within this cluster throughout the day, but the transition to a more surface-based character could introduce the threat for stronger gusts as well. A strengthening low-level jet coupled with persistent mid-level westerlies support the potential for upscale growth in a east-southeastward progressing MCS. Damaging gusts will be possible with this MCS, particularly over SD, but increasing low-level stability should result in a gradually diminishing severe potential with eastward/southeastward extend into northeast NE, northwest IA, and southwest MN. ..Mosier/Bentley.. 08/05/2025 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Tue Aug 05 2025 Valid 081200Z - 131200Z ...DISCUSSION... ...Friday/Day 4 to Sunday/Day 6... On Friday, a mid-level trough and an associated speed max is forecast to move into the northern Plains. At the surface, a moist airmass will be in place over much of the northern Plains, where surface dewpoints are likely to be in the lower to mid 70s F. As surface temperatures warm during the day, moderate to strong instability is expected to develop. Along the northwestern edge of this unstable airmass, thunderstorms should form in parts of central and eastern North Dakota. Convective coverage is forecast to expand southward into South Dakota during the evening. Moderate to strong deep-layer shear associated with the speed max will be favorable for a severe threat during the afternoon and evening. Supercells with large hail, severe wind gusts and a tornado threat will be possible. On Saturday, the mid-level trough and associated cold front are forecast to move eastward into the upper Mississippi and mid Missouri Valleys. Thunderstorms are forecast to be ongoing along and near the front during the morning, with additional thunderstorm development taking place further southeast in the afternoon. Moderate instability and deep-layer shear is forecast across much of the region, suggesting that a severe threat will again be possible. There is some uncertainty as to how much the airmass will be negatively affected by the morning convection. Also, model forecasts suggest that the greatest convective potential will be during the overnight period on Saturday. For this reason, will not add a threat area for Saturday at this time. On Sunday, a mid-level trough is forecast to move across the north-central U.S., being positioned from the northern Plains to the central Rockies by afternoon. A moderately unstable airmass is forecast further to the east, from the upper Mississippi Valley southward into the mid Missouri Valley. An isolated severe threat will be possible Sunday afternoon along and near the instability axis. However, the mid-level trough is forecast to remain well to the west of the instability axis, which should limit large-scale ascent over the unstable airmass, helping to keep any severe threat isolated. ...Monday/Day 7 and Tuesday/Day 8... A low-amplitude mid-level trough is forecast to move into the upper Mississippi Valley on Monday, and into the western Great Lakes on Tuesday. Further southwest, a mid-level low is forecast across the central Plains. Thunderstorms will be possible on Monday and Tuesday afternoon, along the northern edge of a moist airmass from the central Plains northeastward to the Great Lakes. Model forecasts suggest that deep-layer shear will be relatively weak. Although convective coverage and any associated severe threat will likely remain isolated, a few marginally severe storms could occur in areas that heat up the most. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Tue Aug 05 2025 Valid 081200Z - 131200Z ...DISCUSSION... ...Friday/Day 4 to Sunday/Day 6... On Friday, a mid-level trough and an associated speed max is forecast to move into the northern Plains. At the surface, a moist airmass will be in place over much of the northern Plains, where surface dewpoints are likely to be in the lower to mid 70s F. As surface temperatures warm during the day, moderate to strong instability is expected to develop. Along the northwestern edge of this unstable airmass, thunderstorms should form in parts of central and eastern North Dakota. Convective coverage is forecast to expand southward into South Dakota during the evening. Moderate to strong deep-layer shear associated with the speed max will be favorable for a severe threat during the afternoon and evening. Supercells with large hail, severe wind gusts and a tornado threat will be possible. On Saturday, the mid-level trough and associated cold front are forecast to move eastward into the upper Mississippi and mid Missouri Valleys. Thunderstorms are forecast to be ongoing along and near the front during the morning, with additional thunderstorm development taking place further southeast in the afternoon. Moderate instability and deep-layer shear is forecast across much of the region, suggesting that a severe threat will again be possible. There is some uncertainty as to how much the airmass will be negatively affected by the morning convection. Also, model forecasts suggest that the greatest convective potential will be during the overnight period on Saturday. For this reason, will not add a threat area for Saturday at this time. On Sunday, a mid-level trough is forecast to move across the north-central U.S., being positioned from the northern Plains to the central Rockies by afternoon. A moderately unstable airmass is forecast further to the east, from the upper Mississippi Valley southward into the mid Missouri Valley. An isolated severe threat will be possible Sunday afternoon along and near the instability axis. However, the mid-level trough is forecast to remain well to the west of the instability axis, which should limit large-scale ascent over the unstable airmass, helping to keep any severe threat isolated. ...Monday/Day 7 and Tuesday/Day 8... A low-amplitude mid-level trough is forecast to move into the upper Mississippi Valley on Monday, and into the western Great Lakes on Tuesday. Further southwest, a mid-level low is forecast across the central Plains. Thunderstorms will be possible on Monday and Tuesday afternoon, along the northern edge of a moist airmass from the central Plains northeastward to the Great Lakes. Model forecasts suggest that deep-layer shear will be relatively weak. Although convective coverage and any associated severe threat will likely remain isolated, a few marginally severe storms could occur in areas that heat up the most. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Tue Aug 05 2025 Valid 081200Z - 131200Z ...DISCUSSION... ...Friday/Day 4 to Sunday/Day 6... On Friday, a mid-level trough and an associated speed max is forecast to move into the northern Plains. At the surface, a moist airmass will be in place over much of the northern Plains, where surface dewpoints are likely to be in the lower to mid 70s F. As surface temperatures warm during the day, moderate to strong instability is expected to develop. Along the northwestern edge of this unstable airmass, thunderstorms should form in parts of central and eastern North Dakota. Convective coverage is forecast to expand southward into South Dakota during the evening. Moderate to strong deep-layer shear associated with the speed max will be favorable for a severe threat during the afternoon and evening. Supercells with large hail, severe wind gusts and a tornado threat will be possible. On Saturday, the mid-level trough and associated cold front are forecast to move eastward into the upper Mississippi and mid Missouri Valleys. Thunderstorms are forecast to be ongoing along and near the front during the morning, with additional thunderstorm development taking place further southeast in the afternoon. Moderate instability and deep-layer shear is forecast across much of the region, suggesting that a severe threat will again be possible. There is some uncertainty as to how much the airmass will be negatively affected by the morning convection. Also, model forecasts suggest that the greatest convective potential will be during the overnight period on Saturday. For this reason, will not add a threat area for Saturday at this time. On Sunday, a mid-level trough is forecast to move across the north-central U.S., being positioned from the northern Plains to the central Rockies by afternoon. A moderately unstable airmass is forecast further to the east, from the upper Mississippi Valley southward into the mid Missouri Valley. An isolated severe threat will be possible Sunday afternoon along and near the instability axis. However, the mid-level trough is forecast to remain well to the west of the instability axis, which should limit large-scale ascent over the unstable airmass, helping to keep any severe threat isolated. ...Monday/Day 7 and Tuesday/Day 8... A low-amplitude mid-level trough is forecast to move into the upper Mississippi Valley on Monday, and into the western Great Lakes on Tuesday. Further southwest, a mid-level low is forecast across the central Plains. Thunderstorms will be possible on Monday and Tuesday afternoon, along the northern edge of a moist airmass from the central Plains northeastward to the Great Lakes. Model forecasts suggest that deep-layer shear will be relatively weak. Although convective coverage and any associated severe threat will likely remain isolated, a few marginally severe storms could occur in areas that heat up the most. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Tue Aug 05 2025 Valid 081200Z - 131200Z ...DISCUSSION... ...Friday/Day 4 to Sunday/Day 6... On Friday, a mid-level trough and an associated speed max is forecast to move into the northern Plains. At the surface, a moist airmass will be in place over much of the northern Plains, where surface dewpoints are likely to be in the lower to mid 70s F. As surface temperatures warm during the day, moderate to strong instability is expected to develop. Along the northwestern edge of this unstable airmass, thunderstorms should form in parts of central and eastern North Dakota. Convective coverage is forecast to expand southward into South Dakota during the evening. Moderate to strong deep-layer shear associated with the speed max will be favorable for a severe threat during the afternoon and evening. Supercells with large hail, severe wind gusts and a tornado threat will be possible. On Saturday, the mid-level trough and associated cold front are forecast to move eastward into the upper Mississippi and mid Missouri Valleys. Thunderstorms are forecast to be ongoing along and near the front during the morning, with additional thunderstorm development taking place further southeast in the afternoon. Moderate instability and deep-layer shear is forecast across much of the region, suggesting that a severe threat will again be possible. There is some uncertainty as to how much the airmass will be negatively affected by the morning convection. Also, model forecasts suggest that the greatest convective potential will be during the overnight period on Saturday. For this reason, will not add a threat area for Saturday at this time. On Sunday, a mid-level trough is forecast to move across the north-central U.S., being positioned from the northern Plains to the central Rockies by afternoon. A moderately unstable airmass is forecast further to the east, from the upper Mississippi Valley southward into the mid Missouri Valley. An isolated severe threat will be possible Sunday afternoon along and near the instability axis. However, the mid-level trough is forecast to remain well to the west of the instability axis, which should limit large-scale ascent over the unstable airmass, helping to keep any severe threat isolated. ...Monday/Day 7 and Tuesday/Day 8... A low-amplitude mid-level trough is forecast to move into the upper Mississippi Valley on Monday, and into the western Great Lakes on Tuesday. Further southwest, a mid-level low is forecast across the central Plains. Thunderstorms will be possible on Monday and Tuesday afternoon, along the northern edge of a moist airmass from the central Plains northeastward to the Great Lakes. Model forecasts suggest that deep-layer shear will be relatively weak. Although convective coverage and any associated severe threat will likely remain isolated, a few marginally severe storms could occur in areas that heat up the most. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Tue Aug 05 2025 Valid 081200Z - 131200Z ...DISCUSSION... ...Friday/Day 4 to Sunday/Day 6... On Friday, a mid-level trough and an associated speed max is forecast to move into the northern Plains. At the surface, a moist airmass will be in place over much of the northern Plains, where surface dewpoints are likely to be in the lower to mid 70s F. As surface temperatures warm during the day, moderate to strong instability is expected to develop. Along the northwestern edge of this unstable airmass, thunderstorms should form in parts of central and eastern North Dakota. Convective coverage is forecast to expand southward into South Dakota during the evening. Moderate to strong deep-layer shear associated with the speed max will be favorable for a severe threat during the afternoon and evening. Supercells with large hail, severe wind gusts and a tornado threat will be possible. On Saturday, the mid-level trough and associated cold front are forecast to move eastward into the upper Mississippi and mid Missouri Valleys. Thunderstorms are forecast to be ongoing along and near the front during the morning, with additional thunderstorm development taking place further southeast in the afternoon. Moderate instability and deep-layer shear is forecast across much of the region, suggesting that a severe threat will again be possible. There is some uncertainty as to how much the airmass will be negatively affected by the morning convection. Also, model forecasts suggest that the greatest convective potential will be during the overnight period on Saturday. For this reason, will not add a threat area for Saturday at this time. On Sunday, a mid-level trough is forecast to move across the north-central U.S., being positioned from the northern Plains to the central Rockies by afternoon. A moderately unstable airmass is forecast further to the east, from the upper Mississippi Valley southward into the mid Missouri Valley. An isolated severe threat will be possible Sunday afternoon along and near the instability axis. However, the mid-level trough is forecast to remain well to the west of the instability axis, which should limit large-scale ascent over the unstable airmass, helping to keep any severe threat isolated. ...Monday/Day 7 and Tuesday/Day 8... A low-amplitude mid-level trough is forecast to move into the upper Mississippi Valley on Monday, and into the western Great Lakes on Tuesday. Further southwest, a mid-level low is forecast across the central Plains. Thunderstorms will be possible on Monday and Tuesday afternoon, along the northern edge of a moist airmass from the central Plains northeastward to the Great Lakes. Model forecasts suggest that deep-layer shear will be relatively weak. Although convective coverage and any associated severe threat will likely remain isolated, a few marginally severe storms could occur in areas that heat up the most. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Tue Aug 05 2025 Valid 081200Z - 131200Z ...DISCUSSION... ...Friday/Day 4 to Sunday/Day 6... On Friday, a mid-level trough and an associated speed max is forecast to move into the northern Plains. At the surface, a moist airmass will be in place over much of the northern Plains, where surface dewpoints are likely to be in the lower to mid 70s F. As surface temperatures warm during the day, moderate to strong instability is expected to develop. Along the northwestern edge of this unstable airmass, thunderstorms should form in parts of central and eastern North Dakota. Convective coverage is forecast to expand southward into South Dakota during the evening. Moderate to strong deep-layer shear associated with the speed max will be favorable for a severe threat during the afternoon and evening. Supercells with large hail, severe wind gusts and a tornado threat will be possible. On Saturday, the mid-level trough and associated cold front are forecast to move eastward into the upper Mississippi and mid Missouri Valleys. Thunderstorms are forecast to be ongoing along and near the front during the morning, with additional thunderstorm development taking place further southeast in the afternoon. Moderate instability and deep-layer shear is forecast across much of the region, suggesting that a severe threat will again be possible. There is some uncertainty as to how much the airmass will be negatively affected by the morning convection. Also, model forecasts suggest that the greatest convective potential will be during the overnight period on Saturday. For this reason, will not add a threat area for Saturday at this time. On Sunday, a mid-level trough is forecast to move across the north-central U.S., being positioned from the northern Plains to the central Rockies by afternoon. A moderately unstable airmass is forecast further to the east, from the upper Mississippi Valley southward into the mid Missouri Valley. An isolated severe threat will be possible Sunday afternoon along and near the instability axis. However, the mid-level trough is forecast to remain well to the west of the instability axis, which should limit large-scale ascent over the unstable airmass, helping to keep any severe threat isolated. ...Monday/Day 7 and Tuesday/Day 8... A low-amplitude mid-level trough is forecast to move into the upper Mississippi Valley on Monday, and into the western Great Lakes on Tuesday. Further southwest, a mid-level low is forecast across the central Plains. Thunderstorms will be possible on Monday and Tuesday afternoon, along the northern edge of a moist airmass from the central Plains northeastward to the Great Lakes. Model forecasts suggest that deep-layer shear will be relatively weak. Although convective coverage and any associated severe threat will likely remain isolated, a few marginally severe storms could occur in areas that heat up the most. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Tue Aug 05 2025 Valid 081200Z - 131200Z ...DISCUSSION... ...Friday/Day 4 to Sunday/Day 6... On Friday, a mid-level trough and an associated speed max is forecast to move into the northern Plains. At the surface, a moist airmass will be in place over much of the northern Plains, where surface dewpoints are likely to be in the lower to mid 70s F. As surface temperatures warm during the day, moderate to strong instability is expected to develop. Along the northwestern edge of this unstable airmass, thunderstorms should form in parts of central and eastern North Dakota. Convective coverage is forecast to expand southward into South Dakota during the evening. Moderate to strong deep-layer shear associated with the speed max will be favorable for a severe threat during the afternoon and evening. Supercells with large hail, severe wind gusts and a tornado threat will be possible. On Saturday, the mid-level trough and associated cold front are forecast to move eastward into the upper Mississippi and mid Missouri Valleys. Thunderstorms are forecast to be ongoing along and near the front during the morning, with additional thunderstorm development taking place further southeast in the afternoon. Moderate instability and deep-layer shear is forecast across much of the region, suggesting that a severe threat will again be possible. There is some uncertainty as to how much the airmass will be negatively affected by the morning convection. Also, model forecasts suggest that the greatest convective potential will be during the overnight period on Saturday. For this reason, will not add a threat area for Saturday at this time. On Sunday, a mid-level trough is forecast to move across the north-central U.S., being positioned from the northern Plains to the central Rockies by afternoon. A moderately unstable airmass is forecast further to the east, from the upper Mississippi Valley southward into the mid Missouri Valley. An isolated severe threat will be possible Sunday afternoon along and near the instability axis. However, the mid-level trough is forecast to remain well to the west of the instability axis, which should limit large-scale ascent over the unstable airmass, helping to keep any severe threat isolated. ...Monday/Day 7 and Tuesday/Day 8... A low-amplitude mid-level trough is forecast to move into the upper Mississippi Valley on Monday, and into the western Great Lakes on Tuesday. Further southwest, a mid-level low is forecast across the central Plains. Thunderstorms will be possible on Monday and Tuesday afternoon, along the northern edge of a moist airmass from the central Plains northeastward to the Great Lakes. Model forecasts suggest that deep-layer shear will be relatively weak. Although convective coverage and any associated severe threat will likely remain isolated, a few marginally severe storms could occur in areas that heat up the most. Read more

MD 1889 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR FAR SOUTHEAST MONTANA...FAR NORTHEAST WYOMING AND WESTERN SOUTH DAKOTA.
Mesoscale Discussion 1889 NWS Storm Prediction Center Norman OK 0258 AM CDT Tue Aug 05 2025 Areas affected...far southeast Montana...far northeast Wyoming and western South Dakota. Concerning...Severe potential...Watch unlikely Valid 050758Z - 050930Z Probability of Watch Issuance...20 percent SUMMARY...Isolated large hail is possible early this morning across portions of southeast Montana, northeast Wyoming, and western South Dakota. DISCUSSION...The low-level jet has strengthened significantly over the past hour across western South Dakota (now approaching 40 knots on the KUDX VWP). As a result, elevated thunderstorms have increased in coverage across western South Dakota and far southeast Montana. An environment featuring 30 to 40 knots of deep layer shear, 2000 to 2500 J/kg MUCAPE, and support from the low-level jet may result in a few elevated supercells capable of primarily large hail early this morning. In addition, a mature MCS has developed across southeast Montana. As this MCS advances east, at least some severe wind potential could exist if a more consolidated/faster moving segment can emerge from this MCS. At this time, the stronger storm in Powder River, Montana would likely have the greatest potential for this solution as it moves east-southeast along the instability gradient early this morning. Given the isolated nature of the threat, a severe thunderstorm watch is unlikely. ..Bentley/Mosier.. 08/05/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...UNR...BYZ... LAT...LON 44850523 45120566 45320572 45520561 45690440 45650320 45280185 44810143 44080122 43310115 43000191 43020270 43150354 44010408 44590467 44850523 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Tue Aug 05 2025 Valid 071200Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND NORTHERN ROCKIES... ...SUMMARY... Thunderstorms with isolated severe gusts and hail will be possible on Thursday from parts of the northern Plains westward into the northern Rockies. ...Northern Plains... At mid-levels, a shortwave ridge is forecast to move eastward across the northern Plains on Thursday, as a speed max moves over the top of the ridge into southern Canada. At the surface, a moist and unstable airmass will be in place across most of the northern Plains. The ridge will move eastward toward the upper Mississippi Valley during the day. In its wake, isolated convective development is expected during the mid to late afternoon over the western Dakotas. This convection should remain elevated, due to a shallow capping inversion around 750 mb that is evident on forecast soundings. During the early to mid evening, some of the convection could become surface-based and be associated with a potential for isolated severe gusts and hail. ...Northern Rockies... A mid-level trough is forecast to move across the Pacific Northwest on Thursday, as flow remains southwesterly ahead of the trough over the northern Rockies. At the surface, dewpoints are forecast to be from the mid 40s to lower 50s F throughout much of the region. As surface temperatures warm during the day, scattered thunderstorms will likely develop in the higher terrain, with more isolated convection expected along an axis of instability across central Montana. By afternoon, forecast soundings along the axis of instability have weak instability in place (MLCAPE around 500 J/kg), with 0-6 km shear mostly in the 45 to 55 knot range. This, combined with steep low to mid-level lapse rates, should be enough for an isolated severe threat. A few severe wind gusts and hail will be possible. ..Broyles.. 08/05/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Tue Aug 05 2025 Valid 071200Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND NORTHERN ROCKIES... ...SUMMARY... Thunderstorms with isolated severe gusts and hail will be possible on Thursday from parts of the northern Plains westward into the northern Rockies. ...Northern Plains... At mid-levels, a shortwave ridge is forecast to move eastward across the northern Plains on Thursday, as a speed max moves over the top of the ridge into southern Canada. At the surface, a moist and unstable airmass will be in place across most of the northern Plains. The ridge will move eastward toward the upper Mississippi Valley during the day. In its wake, isolated convective development is expected during the mid to late afternoon over the western Dakotas. This convection should remain elevated, due to a shallow capping inversion around 750 mb that is evident on forecast soundings. During the early to mid evening, some of the convection could become surface-based and be associated with a potential for isolated severe gusts and hail. ...Northern Rockies... A mid-level trough is forecast to move across the Pacific Northwest on Thursday, as flow remains southwesterly ahead of the trough over the northern Rockies. At the surface, dewpoints are forecast to be from the mid 40s to lower 50s F throughout much of the region. As surface temperatures warm during the day, scattered thunderstorms will likely develop in the higher terrain, with more isolated convection expected along an axis of instability across central Montana. By afternoon, forecast soundings along the axis of instability have weak instability in place (MLCAPE around 500 J/kg), with 0-6 km shear mostly in the 45 to 55 knot range. This, combined with steep low to mid-level lapse rates, should be enough for an isolated severe threat. A few severe wind gusts and hail will be possible. ..Broyles.. 08/05/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Tue Aug 05 2025 Valid 071200Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND NORTHERN ROCKIES... ...SUMMARY... Thunderstorms with isolated severe gusts and hail will be possible on Thursday from parts of the northern Plains westward into the northern Rockies. ...Northern Plains... At mid-levels, a shortwave ridge is forecast to move eastward across the northern Plains on Thursday, as a speed max moves over the top of the ridge into southern Canada. At the surface, a moist and unstable airmass will be in place across most of the northern Plains. The ridge will move eastward toward the upper Mississippi Valley during the day. In its wake, isolated convective development is expected during the mid to late afternoon over the western Dakotas. This convection should remain elevated, due to a shallow capping inversion around 750 mb that is evident on forecast soundings. During the early to mid evening, some of the convection could become surface-based and be associated with a potential for isolated severe gusts and hail. ...Northern Rockies... A mid-level trough is forecast to move across the Pacific Northwest on Thursday, as flow remains southwesterly ahead of the trough over the northern Rockies. At the surface, dewpoints are forecast to be from the mid 40s to lower 50s F throughout much of the region. As surface temperatures warm during the day, scattered thunderstorms will likely develop in the higher terrain, with more isolated convection expected along an axis of instability across central Montana. By afternoon, forecast soundings along the axis of instability have weak instability in place (MLCAPE around 500 J/kg), with 0-6 km shear mostly in the 45 to 55 knot range. This, combined with steep low to mid-level lapse rates, should be enough for an isolated severe threat. A few severe wind gusts and hail will be possible. ..Broyles.. 08/05/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Tue Aug 05 2025 Valid 071200Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND NORTHERN ROCKIES... ...SUMMARY... Thunderstorms with isolated severe gusts and hail will be possible on Thursday from parts of the northern Plains westward into the northern Rockies. ...Northern Plains... At mid-levels, a shortwave ridge is forecast to move eastward across the northern Plains on Thursday, as a speed max moves over the top of the ridge into southern Canada. At the surface, a moist and unstable airmass will be in place across most of the northern Plains. The ridge will move eastward toward the upper Mississippi Valley during the day. In its wake, isolated convective development is expected during the mid to late afternoon over the western Dakotas. This convection should remain elevated, due to a shallow capping inversion around 750 mb that is evident on forecast soundings. During the early to mid evening, some of the convection could become surface-based and be associated with a potential for isolated severe gusts and hail. ...Northern Rockies... A mid-level trough is forecast to move across the Pacific Northwest on Thursday, as flow remains southwesterly ahead of the trough over the northern Rockies. At the surface, dewpoints are forecast to be from the mid 40s to lower 50s F throughout much of the region. As surface temperatures warm during the day, scattered thunderstorms will likely develop in the higher terrain, with more isolated convection expected along an axis of instability across central Montana. By afternoon, forecast soundings along the axis of instability have weak instability in place (MLCAPE around 500 J/kg), with 0-6 km shear mostly in the 45 to 55 knot range. This, combined with steep low to mid-level lapse rates, should be enough for an isolated severe threat. A few severe wind gusts and hail will be possible. ..Broyles.. 08/05/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Tue Aug 05 2025 Valid 071200Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND NORTHERN ROCKIES... ...SUMMARY... Thunderstorms with isolated severe gusts and hail will be possible on Thursday from parts of the northern Plains westward into the northern Rockies. ...Northern Plains... At mid-levels, a shortwave ridge is forecast to move eastward across the northern Plains on Thursday, as a speed max moves over the top of the ridge into southern Canada. At the surface, a moist and unstable airmass will be in place across most of the northern Plains. The ridge will move eastward toward the upper Mississippi Valley during the day. In its wake, isolated convective development is expected during the mid to late afternoon over the western Dakotas. This convection should remain elevated, due to a shallow capping inversion around 750 mb that is evident on forecast soundings. During the early to mid evening, some of the convection could become surface-based and be associated with a potential for isolated severe gusts and hail. ...Northern Rockies... A mid-level trough is forecast to move across the Pacific Northwest on Thursday, as flow remains southwesterly ahead of the trough over the northern Rockies. At the surface, dewpoints are forecast to be from the mid 40s to lower 50s F throughout much of the region. As surface temperatures warm during the day, scattered thunderstorms will likely develop in the higher terrain, with more isolated convection expected along an axis of instability across central Montana. By afternoon, forecast soundings along the axis of instability have weak instability in place (MLCAPE around 500 J/kg), with 0-6 km shear mostly in the 45 to 55 knot range. This, combined with steep low to mid-level lapse rates, should be enough for an isolated severe threat. A few severe wind gusts and hail will be possible. ..Broyles.. 08/05/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Tue Aug 05 2025 Valid 071200Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND NORTHERN ROCKIES... ...SUMMARY... Thunderstorms with isolated severe gusts and hail will be possible on Thursday from parts of the northern Plains westward into the northern Rockies. ...Northern Plains... At mid-levels, a shortwave ridge is forecast to move eastward across the northern Plains on Thursday, as a speed max moves over the top of the ridge into southern Canada. At the surface, a moist and unstable airmass will be in place across most of the northern Plains. The ridge will move eastward toward the upper Mississippi Valley during the day. In its wake, isolated convective development is expected during the mid to late afternoon over the western Dakotas. This convection should remain elevated, due to a shallow capping inversion around 750 mb that is evident on forecast soundings. During the early to mid evening, some of the convection could become surface-based and be associated with a potential for isolated severe gusts and hail. ...Northern Rockies... A mid-level trough is forecast to move across the Pacific Northwest on Thursday, as flow remains southwesterly ahead of the trough over the northern Rockies. At the surface, dewpoints are forecast to be from the mid 40s to lower 50s F throughout much of the region. As surface temperatures warm during the day, scattered thunderstorms will likely develop in the higher terrain, with more isolated convection expected along an axis of instability across central Montana. By afternoon, forecast soundings along the axis of instability have weak instability in place (MLCAPE around 500 J/kg), with 0-6 km shear mostly in the 45 to 55 knot range. This, combined with steep low to mid-level lapse rates, should be enough for an isolated severe threat. A few severe wind gusts and hail will be possible. ..Broyles.. 08/05/2025 Read more