Severe Storms

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0720 AM CDT Sun Aug 17 2025 Valid 171300Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS...UPPER MIDWEST...MID ATLANTIC...AND SOUTHERN NEW ENGLAND.... ...SUMMARY... One or two clusters of thunderstorms may develop and gradually pose a risk for damaging wind gusts from the northern High Plains into the Midwest this afternoon and tonight. Damaging thunderstorm wind gusts may also occur across parts of the northern Mid Atlantic into southern New England late this afternoon and evening. ...Northern Plains into Upper Midwest... A broad upper ridge remains in place over southern/central U.S today. Several weak perturbations will top the ridge during this forecast period, affecting much of the northern Plains and upper Midwest. Each of these smaller-scale shortwave troughs will potentially be associated with a cluster of thunderstorms. Sufficient low-level moisture and 25-35 knots of westerly flow aloft pose some conditional risk of severe storms throughout this region, but considerable uncertainty on the timing and placement of convection precludes upgrading any areas to SLGT at this time. Multiple areas of ongoing convection this morning further complicate the forecast. Perhaps by 1630z, areas of stronger daytime heating/destabilization will allow better focus of the severe outlook. ...Mid Atlantic into southern New England... A cold front currently extends from OH northeastward into the St. Lawrence Valley. Forecast soundings ahead of the front show weak mid-level lapse rates and limited mid-level dry air. However, strong heating into the 80s and 90s F, coupled with dewpoints near 70F will yield MLCAPE around 1000 J/kg. Sufficient westerly flow aloft and frontal forcing may be sufficient for isolated strong storms capable of locally gusty/damaging winds this afternoon. ..Hart/Dean.. 08/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0720 AM CDT Sun Aug 17 2025 Valid 171300Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS...UPPER MIDWEST...MID ATLANTIC...AND SOUTHERN NEW ENGLAND.... ...SUMMARY... One or two clusters of thunderstorms may develop and gradually pose a risk for damaging wind gusts from the northern High Plains into the Midwest this afternoon and tonight. Damaging thunderstorm wind gusts may also occur across parts of the northern Mid Atlantic into southern New England late this afternoon and evening. ...Northern Plains into Upper Midwest... A broad upper ridge remains in place over southern/central U.S today. Several weak perturbations will top the ridge during this forecast period, affecting much of the northern Plains and upper Midwest. Each of these smaller-scale shortwave troughs will potentially be associated with a cluster of thunderstorms. Sufficient low-level moisture and 25-35 knots of westerly flow aloft pose some conditional risk of severe storms throughout this region, but considerable uncertainty on the timing and placement of convection precludes upgrading any areas to SLGT at this time. Multiple areas of ongoing convection this morning further complicate the forecast. Perhaps by 1630z, areas of stronger daytime heating/destabilization will allow better focus of the severe outlook. ...Mid Atlantic into southern New England... A cold front currently extends from OH northeastward into the St. Lawrence Valley. Forecast soundings ahead of the front show weak mid-level lapse rates and limited mid-level dry air. However, strong heating into the 80s and 90s F, coupled with dewpoints near 70F will yield MLCAPE around 1000 J/kg. Sufficient westerly flow aloft and frontal forcing may be sufficient for isolated strong storms capable of locally gusty/damaging winds this afternoon. ..Hart/Dean.. 08/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0720 AM CDT Sun Aug 17 2025 Valid 171300Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS...UPPER MIDWEST...MID ATLANTIC...AND SOUTHERN NEW ENGLAND.... ...SUMMARY... One or two clusters of thunderstorms may develop and gradually pose a risk for damaging wind gusts from the northern High Plains into the Midwest this afternoon and tonight. Damaging thunderstorm wind gusts may also occur across parts of the northern Mid Atlantic into southern New England late this afternoon and evening. ...Northern Plains into Upper Midwest... A broad upper ridge remains in place over southern/central U.S today. Several weak perturbations will top the ridge during this forecast period, affecting much of the northern Plains and upper Midwest. Each of these smaller-scale shortwave troughs will potentially be associated with a cluster of thunderstorms. Sufficient low-level moisture and 25-35 knots of westerly flow aloft pose some conditional risk of severe storms throughout this region, but considerable uncertainty on the timing and placement of convection precludes upgrading any areas to SLGT at this time. Multiple areas of ongoing convection this morning further complicate the forecast. Perhaps by 1630z, areas of stronger daytime heating/destabilization will allow better focus of the severe outlook. ...Mid Atlantic into southern New England... A cold front currently extends from OH northeastward into the St. Lawrence Valley. Forecast soundings ahead of the front show weak mid-level lapse rates and limited mid-level dry air. However, strong heating into the 80s and 90s F, coupled with dewpoints near 70F will yield MLCAPE around 1000 J/kg. Sufficient westerly flow aloft and frontal forcing may be sufficient for isolated strong storms capable of locally gusty/damaging winds this afternoon. ..Hart/Dean.. 08/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0720 AM CDT Sun Aug 17 2025 Valid 171300Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS...UPPER MIDWEST...MID ATLANTIC...AND SOUTHERN NEW ENGLAND.... ...SUMMARY... One or two clusters of thunderstorms may develop and gradually pose a risk for damaging wind gusts from the northern High Plains into the Midwest this afternoon and tonight. Damaging thunderstorm wind gusts may also occur across parts of the northern Mid Atlantic into southern New England late this afternoon and evening. ...Northern Plains into Upper Midwest... A broad upper ridge remains in place over southern/central U.S today. Several weak perturbations will top the ridge during this forecast period, affecting much of the northern Plains and upper Midwest. Each of these smaller-scale shortwave troughs will potentially be associated with a cluster of thunderstorms. Sufficient low-level moisture and 25-35 knots of westerly flow aloft pose some conditional risk of severe storms throughout this region, but considerable uncertainty on the timing and placement of convection precludes upgrading any areas to SLGT at this time. Multiple areas of ongoing convection this morning further complicate the forecast. Perhaps by 1630z, areas of stronger daytime heating/destabilization will allow better focus of the severe outlook. ...Mid Atlantic into southern New England... A cold front currently extends from OH northeastward into the St. Lawrence Valley. Forecast soundings ahead of the front show weak mid-level lapse rates and limited mid-level dry air. However, strong heating into the 80s and 90s F, coupled with dewpoints near 70F will yield MLCAPE around 1000 J/kg. Sufficient westerly flow aloft and frontal forcing may be sufficient for isolated strong storms capable of locally gusty/damaging winds this afternoon. ..Hart/Dean.. 08/17/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0720 AM CDT Sun Aug 17 2025 Valid 171300Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS...UPPER MIDWEST...MID ATLANTIC...AND SOUTHERN NEW ENGLAND.... ...SUMMARY... One or two clusters of thunderstorms may develop and gradually pose a risk for damaging wind gusts from the northern High Plains into the Midwest this afternoon and tonight. Damaging thunderstorm wind gusts may also occur across parts of the northern Mid Atlantic into southern New England late this afternoon and evening. ...Northern Plains into Upper Midwest... A broad upper ridge remains in place over southern/central U.S today. Several weak perturbations will top the ridge during this forecast period, affecting much of the northern Plains and upper Midwest. Each of these smaller-scale shortwave troughs will potentially be associated with a cluster of thunderstorms. Sufficient low-level moisture and 25-35 knots of westerly flow aloft pose some conditional risk of severe storms throughout this region, but considerable uncertainty on the timing and placement of convection precludes upgrading any areas to SLGT at this time. Multiple areas of ongoing convection this morning further complicate the forecast. Perhaps by 1630z, areas of stronger daytime heating/destabilization will allow better focus of the severe outlook. ...Mid Atlantic into southern New England... A cold front currently extends from OH northeastward into the St. Lawrence Valley. Forecast soundings ahead of the front show weak mid-level lapse rates and limited mid-level dry air. However, strong heating into the 80s and 90s F, coupled with dewpoints near 70F will yield MLCAPE around 1000 J/kg. Sufficient westerly flow aloft and frontal forcing may be sufficient for isolated strong storms capable of locally gusty/damaging winds this afternoon. ..Hart/Dean.. 08/17/2025 Read more

MD 1972 CONCERNING SEVERE THUNDERSTORM WATCH 597... FOR SOUTH-CENTRAL/SOUTHEAST ND INTO NORTHEAST SD
Mesoscale Discussion 1972 NWS Storm Prediction Center Norman OK 0548 AM CDT Sun Aug 17 2025 Areas affected...South-central/southeast ND into northeast SD Concerning...Severe Thunderstorm Watch 597... Valid 171048Z - 171215Z The severe weather threat for Severe Thunderstorm Watch 597 continues. SUMMARY...Some threat for localized strong to severe gusts may continue through dawn. DISCUSSION...A bowing MCS has evolved across south-central ND into north-central SD. While this MCS appears relatively well organized, recent observed wind gusts have generally been subsevere, potentially due to relatively cool/stable near-surface conditions and the lack of a stronger cold pool. The well defined MCV associated with this system, favorable downstream buoyancy (with MUCAPE of 2000-3000 J/kg), and a modest southeasterly low-level jet should help to maintain this MCS as it moves northeastward through dawn. Strong to locally severe gusts and perhaps isolated hail may still accompany this MCS, especially where preceding storms get absorbed into the primary convective line. The need for eventual downstream watch issuance is uncertain, given the relative lack of severe gusts thus far, but trends will continue to be monitored for an uptick in severe-wind potential. ..Dean/Hart.. 08/17/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGF...FSD...ABR...BIS... LAT...LON 46690087 46800119 47080087 47140023 47219933 46959825 46429759 45969747 44829775 44429819 44209957 45899985 46310004 46690087 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN Read more

WW 0597 Status Updates
STATUS REPORT ON WW 597 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 50 SSW PHP TO 50 SE BIS TO 25 SE BIS TO 40 ESE DIK. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1972 ..DEAN..08/17/25 ATTN...WFO...BIS...ABR...UNR... STATUS REPORT FOR WS 597 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NDC015-021-045-047-051-059-171240- ND . NORTH DAKOTA COUNTIES INCLUDED ARE BURLEIGH DICKEY LAMOURE LOGAN MCINTOSH MORTON SDC013-017-021-041-045-049-059-065-069-075-085-089-107-115-117- 119-129-171240- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BROWN BUFFALO CAMPBELL DEWEY EDMUNDS FAULK HAND HUGHES HYDE JONES LYMAN MCPHERSON POTTER SPINK STANLEY SULLY WALWORTH Read more

WW 597 SEVERE TSTM ND SD 170400Z - 171200Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 597 NWS Storm Prediction Center Norman OK 1100 PM CDT Sat Aug 16 2025 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southern North Dakota Western into Central and Northern South Dakota * Effective this Saturday night and Sunday morning from 1100 PM until 700 AM CDT. * Primary threats include... Scattered damaging winds and isolated significant gusts to 75 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Thunderstorms are forecast to continue to develop and intensify late this evening into the overnight across the Watch area. A linear cluster of thunderstorms will likely evolve and move generally west to east across the Watch tonight. Scattered severe gusts (60-75 mph) appear to be the main hazard with the stronger thunderstorm cores and outflow surges. Isolated large hail may accompany the stronger thunderstorms too. The severe thunderstorm watch area is approximately along and 80 statute miles north and south of a line from 60 miles south southwest of Buffalo SD to 5 miles southeast of Aberdeen SD. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU7). 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 1.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 25020. ...Smith Read more

WW 0597 Status Updates
STATUS REPORT ON WW 597 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 50 SE RAP TO 50 SSE Y22 TO 35 E Y22 TO 5 ENE Y22 TO 25 NNW Y22. ..DEAN..08/17/25 ATTN...WFO...BIS...ABR...UNR... STATUS REPORT FOR WS 597 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NDC015-021-029-037-045-047-051-059-085-171040- ND . NORTH DAKOTA COUNTIES INCLUDED ARE BURLEIGH DICKEY EMMONS GRANT LAMOURE LOGAN MCINTOSH MORTON SIOUX SDC013-017-021-031-041-045-049-055-059-065-069-075-085-089-107- 115-117-119-129-137-171040- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BROWN BUFFALO CAMPBELL CORSON DEWEY EDMUNDS FAULK HAAKON HAND HUGHES HYDE JONES LYMAN MCPHERSON POTTER SPINK STANLEY SULLY WALWORTH ZIEBACH Read more

WW 0597 Status Updates
STATUS REPORT ON WW 597 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 50 SE RAP TO 50 SSE Y22 TO 35 E Y22 TO 5 ENE Y22 TO 25 NNW Y22. ..DEAN..08/17/25 ATTN...WFO...BIS...ABR...UNR... STATUS REPORT FOR WS 597 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NDC015-021-029-037-045-047-051-059-085-171040- ND . NORTH DAKOTA COUNTIES INCLUDED ARE BURLEIGH DICKEY EMMONS GRANT LAMOURE LOGAN MCINTOSH MORTON SIOUX SDC013-017-021-031-041-045-049-055-059-065-069-075-085-089-107- 115-117-119-129-137-171040- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BROWN BUFFALO CAMPBELL CORSON DEWEY EDMUNDS FAULK HAAKON HAND HUGHES HYDE JONES LYMAN MCPHERSON POTTER SPINK STANLEY SULLY WALWORTH ZIEBACH Read more

MD 1971 CONCERNING SEVERE THUNDERSTORM WATCH 597... FOR NORTHWEST/NORTH-CENTRAL SD INTO SOUTHWEST/SOUTH-CENTRAL ND
Mesoscale Discussion 1971 NWS Storm Prediction Center Norman OK 0247 AM CDT Sun Aug 17 2025 Areas affected...Northwest/north-central SD into southwest/south-central ND Concerning...Severe Thunderstorm Watch 597... Valid 170747Z - 170915Z The severe weather threat for Severe Thunderstorm Watch 597 continues. SUMMARY...An increase in the severe-wind threat remains possible overnight. DISCUSSION...A storm cluster over western SD has shown signs of becoming better organized over the last 30-60 minutes, with indications of bow-echo development across northwest SD, and recent observed wind gusts of 50-60 mph. MUCAPE remains in the 2500-4000 J/kg range, due to steep midlevel lapse rates atop a richly moist boundary layer (as observed in the 00Z UNR sounding). Meanwhile, backed low-level flow beneath modest southwesterlies aloft is supporting effective shear of 25-35 kt, sufficient for organized convection. A modest nocturnal low-level jet combined with the favorable instability and deep-layer shear will support continued intensification of the ongoing cluster, and maintenance of this cluster through much of the overnight hours. Short-term guidance suggests that this developing MCS will generally move northeastward along the MUCAPE and low-level moisture gradient. The magnitude of the wind threat remains somewhat uncertain, due to the presence of low-level stability and surface-based CINH. However, if an organized MCS does persist, some increase in severe-wind potential is expected overnight from northern SD into southern ND. ..Dean.. 08/17/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ABR...BIS...UNR... LAT...LON 45690234 46320209 46540110 46709979 45869933 45339923 44759944 44280019 44370204 45240186 45690234 MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CDT Sun Aug 17 2025 Valid 201200Z - 251200Z ...DISCUSSION... ...Wednesday/Day 4 to Friday/Day 6... On Wednesday, a mid-level ridge will likely be in place across the northern Plains. At the surface, a front is forecast to be located over the Ozarks and lower Ohio Valley. Moderate instability is expected to develop to the south of the front, and over parts of the north-central states. In areas where storms are expected, deep-layer shear should be weak, suggesting a severe threat is unlikely. On Thursday, a mid-level shortwave trough and an associated cold front are forecast to move eastward into the northern Plains. An axis of moderate instability is forecast ahead of the front. This combined with moderate deep-layer shear could be enough for an isolated severe threat during the afternoon and evening, mainly over eastern North Dakota and northwestern Minnesota. The front and its associated shortwave trough are forecast to move into the upper Mississippi and mid Missouri Valleys on Friday. Moderate instability appears likely to develop ahead of the front during the afternoon. Along and near the instability axis, the greatest potential for thunderstorm development could occur in the central Plains within northwest mid-level flow. An isolated severe threat will be possible during the late afternoon and early evening. ...Saturday/Day 7 and Sunday/Day 8... On Saturday and Sunday, an upper-level trough is forecast to remain over the Great Lakes region. Ahead of the trough, an axis of instability is forecast to develop in the central Appalachians, where isolated to scattered thunderstorms will be possible each afternoon. Moderate deep-layer shear could be sufficient for an isolated wind-damage threat, mainly in the late afternoon as low-level lapse rates become steep. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CDT Sun Aug 17 2025 Valid 201200Z - 251200Z ...DISCUSSION... ...Wednesday/Day 4 to Friday/Day 6... On Wednesday, a mid-level ridge will likely be in place across the northern Plains. At the surface, a front is forecast to be located over the Ozarks and lower Ohio Valley. Moderate instability is expected to develop to the south of the front, and over parts of the north-central states. In areas where storms are expected, deep-layer shear should be weak, suggesting a severe threat is unlikely. On Thursday, a mid-level shortwave trough and an associated cold front are forecast to move eastward into the northern Plains. An axis of moderate instability is forecast ahead of the front. This combined with moderate deep-layer shear could be enough for an isolated severe threat during the afternoon and evening, mainly over eastern North Dakota and northwestern Minnesota. The front and its associated shortwave trough are forecast to move into the upper Mississippi and mid Missouri Valleys on Friday. Moderate instability appears likely to develop ahead of the front during the afternoon. Along and near the instability axis, the greatest potential for thunderstorm development could occur in the central Plains within northwest mid-level flow. An isolated severe threat will be possible during the late afternoon and early evening. ...Saturday/Day 7 and Sunday/Day 8... On Saturday and Sunday, an upper-level trough is forecast to remain over the Great Lakes region. Ahead of the trough, an axis of instability is forecast to develop in the central Appalachians, where isolated to scattered thunderstorms will be possible each afternoon. Moderate deep-layer shear could be sufficient for an isolated wind-damage threat, mainly in the late afternoon as low-level lapse rates become steep. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CDT Sun Aug 17 2025 Valid 201200Z - 251200Z ...DISCUSSION... ...Wednesday/Day 4 to Friday/Day 6... On Wednesday, a mid-level ridge will likely be in place across the northern Plains. At the surface, a front is forecast to be located over the Ozarks and lower Ohio Valley. Moderate instability is expected to develop to the south of the front, and over parts of the north-central states. In areas where storms are expected, deep-layer shear should be weak, suggesting a severe threat is unlikely. On Thursday, a mid-level shortwave trough and an associated cold front are forecast to move eastward into the northern Plains. An axis of moderate instability is forecast ahead of the front. This combined with moderate deep-layer shear could be enough for an isolated severe threat during the afternoon and evening, mainly over eastern North Dakota and northwestern Minnesota. The front and its associated shortwave trough are forecast to move into the upper Mississippi and mid Missouri Valleys on Friday. Moderate instability appears likely to develop ahead of the front during the afternoon. Along and near the instability axis, the greatest potential for thunderstorm development could occur in the central Plains within northwest mid-level flow. An isolated severe threat will be possible during the late afternoon and early evening. ...Saturday/Day 7 and Sunday/Day 8... On Saturday and Sunday, an upper-level trough is forecast to remain over the Great Lakes region. Ahead of the trough, an axis of instability is forecast to develop in the central Appalachians, where isolated to scattered thunderstorms will be possible each afternoon. Moderate deep-layer shear could be sufficient for an isolated wind-damage threat, mainly in the late afternoon as low-level lapse rates become steep. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CDT Sun Aug 17 2025 Valid 201200Z - 251200Z ...DISCUSSION... ...Wednesday/Day 4 to Friday/Day 6... On Wednesday, a mid-level ridge will likely be in place across the northern Plains. At the surface, a front is forecast to be located over the Ozarks and lower Ohio Valley. Moderate instability is expected to develop to the south of the front, and over parts of the north-central states. In areas where storms are expected, deep-layer shear should be weak, suggesting a severe threat is unlikely. On Thursday, a mid-level shortwave trough and an associated cold front are forecast to move eastward into the northern Plains. An axis of moderate instability is forecast ahead of the front. This combined with moderate deep-layer shear could be enough for an isolated severe threat during the afternoon and evening, mainly over eastern North Dakota and northwestern Minnesota. The front and its associated shortwave trough are forecast to move into the upper Mississippi and mid Missouri Valleys on Friday. Moderate instability appears likely to develop ahead of the front during the afternoon. Along and near the instability axis, the greatest potential for thunderstorm development could occur in the central Plains within northwest mid-level flow. An isolated severe threat will be possible during the late afternoon and early evening. ...Saturday/Day 7 and Sunday/Day 8... On Saturday and Sunday, an upper-level trough is forecast to remain over the Great Lakes region. Ahead of the trough, an axis of instability is forecast to develop in the central Appalachians, where isolated to scattered thunderstorms will be possible each afternoon. Moderate deep-layer shear could be sufficient for an isolated wind-damage threat, mainly in the late afternoon as low-level lapse rates become steep. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CDT Sun Aug 17 2025 Valid 201200Z - 251200Z ...DISCUSSION... ...Wednesday/Day 4 to Friday/Day 6... On Wednesday, a mid-level ridge will likely be in place across the northern Plains. At the surface, a front is forecast to be located over the Ozarks and lower Ohio Valley. Moderate instability is expected to develop to the south of the front, and over parts of the north-central states. In areas where storms are expected, deep-layer shear should be weak, suggesting a severe threat is unlikely. On Thursday, a mid-level shortwave trough and an associated cold front are forecast to move eastward into the northern Plains. An axis of moderate instability is forecast ahead of the front. This combined with moderate deep-layer shear could be enough for an isolated severe threat during the afternoon and evening, mainly over eastern North Dakota and northwestern Minnesota. The front and its associated shortwave trough are forecast to move into the upper Mississippi and mid Missouri Valleys on Friday. Moderate instability appears likely to develop ahead of the front during the afternoon. Along and near the instability axis, the greatest potential for thunderstorm development could occur in the central Plains within northwest mid-level flow. An isolated severe threat will be possible during the late afternoon and early evening. ...Saturday/Day 7 and Sunday/Day 8... On Saturday and Sunday, an upper-level trough is forecast to remain over the Great Lakes region. Ahead of the trough, an axis of instability is forecast to develop in the central Appalachians, where isolated to scattered thunderstorms will be possible each afternoon. Moderate deep-layer shear could be sufficient for an isolated wind-damage threat, mainly in the late afternoon as low-level lapse rates become steep. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CDT Sun Aug 17 2025 Valid 201200Z - 251200Z ...DISCUSSION... ...Wednesday/Day 4 to Friday/Day 6... On Wednesday, a mid-level ridge will likely be in place across the northern Plains. At the surface, a front is forecast to be located over the Ozarks and lower Ohio Valley. Moderate instability is expected to develop to the south of the front, and over parts of the north-central states. In areas where storms are expected, deep-layer shear should be weak, suggesting a severe threat is unlikely. On Thursday, a mid-level shortwave trough and an associated cold front are forecast to move eastward into the northern Plains. An axis of moderate instability is forecast ahead of the front. This combined with moderate deep-layer shear could be enough for an isolated severe threat during the afternoon and evening, mainly over eastern North Dakota and northwestern Minnesota. The front and its associated shortwave trough are forecast to move into the upper Mississippi and mid Missouri Valleys on Friday. Moderate instability appears likely to develop ahead of the front during the afternoon. Along and near the instability axis, the greatest potential for thunderstorm development could occur in the central Plains within northwest mid-level flow. An isolated severe threat will be possible during the late afternoon and early evening. ...Saturday/Day 7 and Sunday/Day 8... On Saturday and Sunday, an upper-level trough is forecast to remain over the Great Lakes region. Ahead of the trough, an axis of instability is forecast to develop in the central Appalachians, where isolated to scattered thunderstorms will be possible each afternoon. Moderate deep-layer shear could be sufficient for an isolated wind-damage threat, mainly in the late afternoon as low-level lapse rates become steep. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CDT Sun Aug 17 2025 Valid 201200Z - 251200Z ...DISCUSSION... ...Wednesday/Day 4 to Friday/Day 6... On Wednesday, a mid-level ridge will likely be in place across the northern Plains. At the surface, a front is forecast to be located over the Ozarks and lower Ohio Valley. Moderate instability is expected to develop to the south of the front, and over parts of the north-central states. In areas where storms are expected, deep-layer shear should be weak, suggesting a severe threat is unlikely. On Thursday, a mid-level shortwave trough and an associated cold front are forecast to move eastward into the northern Plains. An axis of moderate instability is forecast ahead of the front. This combined with moderate deep-layer shear could be enough for an isolated severe threat during the afternoon and evening, mainly over eastern North Dakota and northwestern Minnesota. The front and its associated shortwave trough are forecast to move into the upper Mississippi and mid Missouri Valleys on Friday. Moderate instability appears likely to develop ahead of the front during the afternoon. Along and near the instability axis, the greatest potential for thunderstorm development could occur in the central Plains within northwest mid-level flow. An isolated severe threat will be possible during the late afternoon and early evening. ...Saturday/Day 7 and Sunday/Day 8... On Saturday and Sunday, an upper-level trough is forecast to remain over the Great Lakes region. Ahead of the trough, an axis of instability is forecast to develop in the central Appalachians, where isolated to scattered thunderstorms will be possible each afternoon. Moderate deep-layer shear could be sufficient for an isolated wind-damage threat, mainly in the late afternoon as low-level lapse rates become steep. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CDT Sun Aug 17 2025 Valid 201200Z - 251200Z ...DISCUSSION... ...Wednesday/Day 4 to Friday/Day 6... On Wednesday, a mid-level ridge will likely be in place across the northern Plains. At the surface, a front is forecast to be located over the Ozarks and lower Ohio Valley. Moderate instability is expected to develop to the south of the front, and over parts of the north-central states. In areas where storms are expected, deep-layer shear should be weak, suggesting a severe threat is unlikely. On Thursday, a mid-level shortwave trough and an associated cold front are forecast to move eastward into the northern Plains. An axis of moderate instability is forecast ahead of the front. This combined with moderate deep-layer shear could be enough for an isolated severe threat during the afternoon and evening, mainly over eastern North Dakota and northwestern Minnesota. The front and its associated shortwave trough are forecast to move into the upper Mississippi and mid Missouri Valleys on Friday. Moderate instability appears likely to develop ahead of the front during the afternoon. Along and near the instability axis, the greatest potential for thunderstorm development could occur in the central Plains within northwest mid-level flow. An isolated severe threat will be possible during the late afternoon and early evening. ...Saturday/Day 7 and Sunday/Day 8... On Saturday and Sunday, an upper-level trough is forecast to remain over the Great Lakes region. Ahead of the trough, an axis of instability is forecast to develop in the central Appalachians, where isolated to scattered thunderstorms will be possible each afternoon. Moderate deep-layer shear could be sufficient for an isolated wind-damage threat, mainly in the late afternoon as low-level lapse rates become steep. Read more

WW 0597 Status Updates
STATUS REPORT ON WW 597 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 65 WSW RAP TO 55 NNE RAP TO 15 S Y22 TO 30 NNW Y22. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1971 ..DEAN..08/17/25 ATTN...WFO...BIS...ABR...UNR... STATUS REPORT FOR WS 597 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NDC015-021-029-037-045-047-051-059-085-170940- ND . NORTH DAKOTA COUNTIES INCLUDED ARE BURLEIGH DICKEY EMMONS GRANT LAMOURE LOGAN MCINTOSH MORTON SIOUX SDC013-017-021-031-041-045-049-055-059-065-069-075-085-089-093- 105-107-115-117-119-129-137-170940- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BROWN BUFFALO CAMPBELL CORSON DEWEY EDMUNDS FAULK HAAKON HAND HUGHES HYDE JONES LYMAN MCPHERSON MEADE PERKINS POTTER SPINK STANLEY SULLY WALWORTH Read more