Severe Storms

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0152 AM CDT Tue Jul 15 2025 Valid 181200Z - 231200Z ...DISCUSSION... Low-amplitude/zonal westerly mid/upper flow is forecast across the northern U.S. for much of the Day 4-8 period. At the same time, the subtropical upper ridge/high over the Southeast will spread westward, with larger-scale upper ridging developing over the central U.S. late in the forecast period. Seasonally moist and unstable conditions will exist for much of the CONUS east of the Rockies. This will lead to daily thunderstorm activity, particularly for parts of the northern/central Plains to the Midwest and Mid-Atlantic regions. These areas will generally be on the north side of the subtropic high and the southern fringes of any stronger westerly flow near the international border. However, a lack of any stronger forcing for ascent or notable surface features precludes severe probabilities. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0152 AM CDT Tue Jul 15 2025 Valid 181200Z - 231200Z ...DISCUSSION... Low-amplitude/zonal westerly mid/upper flow is forecast across the northern U.S. for much of the Day 4-8 period. At the same time, the subtropical upper ridge/high over the Southeast will spread westward, with larger-scale upper ridging developing over the central U.S. late in the forecast period. Seasonally moist and unstable conditions will exist for much of the CONUS east of the Rockies. This will lead to daily thunderstorm activity, particularly for parts of the northern/central Plains to the Midwest and Mid-Atlantic regions. These areas will generally be on the north side of the subtropic high and the southern fringes of any stronger westerly flow near the international border. However, a lack of any stronger forcing for ascent or notable surface features precludes severe probabilities. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0152 AM CDT Tue Jul 15 2025 Valid 181200Z - 231200Z ...DISCUSSION... Low-amplitude/zonal westerly mid/upper flow is forecast across the northern U.S. for much of the Day 4-8 period. At the same time, the subtropical upper ridge/high over the Southeast will spread westward, with larger-scale upper ridging developing over the central U.S. late in the forecast period. Seasonally moist and unstable conditions will exist for much of the CONUS east of the Rockies. This will lead to daily thunderstorm activity, particularly for parts of the northern/central Plains to the Midwest and Mid-Atlantic regions. These areas will generally be on the north side of the subtropic high and the southern fringes of any stronger westerly flow near the international border. However, a lack of any stronger forcing for ascent or notable surface features precludes severe probabilities. Read more

WW 0512 Status Updates
STATUS REPORT ON WW 512 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 SW JMS TO 35 NNE JMS TO 30 SW HCO. ..BENTLEY..07/15/25 ATTN...WFO...FGF...DLH...BIS... STATUS REPORT FOR WS 512 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC005-007-021-027-029-057-061-071-087-089-107-113-119-125- 150740- MN . MINNESOTA COUNTIES INCLUDED ARE BECKER BELTRAMI CASS CLAY CLEARWATER HUBBARD ITASCA KOOCHICHING MAHNOMEN MARSHALL NORMAN PENNINGTON POLK RED LAKE NDC003-017-035-039-091-097-150740- ND . NORTH DAKOTA COUNTIES INCLUDED ARE BARNES CASS GRAND FORKS GRIGGS STEELE TRAILL THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES Read more

WW 0512 Status Updates
STATUS REPORT ON WW 512 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 SW JMS TO 35 NNE JMS TO 30 SW HCO. ..BENTLEY..07/15/25 ATTN...WFO...FGF...DLH...BIS... STATUS REPORT FOR WS 512 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC005-007-021-027-029-057-061-071-087-089-107-113-119-125- 150740- MN . MINNESOTA COUNTIES INCLUDED ARE BECKER BELTRAMI CASS CLAY CLEARWATER HUBBARD ITASCA KOOCHICHING MAHNOMEN MARSHALL NORMAN PENNINGTON POLK RED LAKE NDC003-017-035-039-091-097-150740- ND . NORTH DAKOTA COUNTIES INCLUDED ARE BARNES CASS GRAND FORKS GRIGGS STEELE TRAILL THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES Read more

WW 0512 Status Updates
STATUS REPORT ON WW 512 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 SW JMS TO 35 NNE JMS TO 30 SW HCO. ..BENTLEY..07/15/25 ATTN...WFO...FGF...DLH...BIS... STATUS REPORT FOR WS 512 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC005-007-021-027-029-057-061-071-087-089-107-113-119-125- 150740- MN . MINNESOTA COUNTIES INCLUDED ARE BECKER BELTRAMI CASS CLAY CLEARWATER HUBBARD ITASCA KOOCHICHING MAHNOMEN MARSHALL NORMAN PENNINGTON POLK RED LAKE NDC003-017-035-039-091-097-150740- ND . NORTH DAKOTA COUNTIES INCLUDED ARE BARNES CASS GRAND FORKS GRIGGS STEELE TRAILL THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES Read more

WW 512 SEVERE TSTM MN ND 150425Z - 151100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 512 NWS Storm Prediction Center Norman OK 1125 PM CDT Mon Jul 14 2025 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northern Minnesota East central North Dakota * Effective this Monday night and Tuesday morning from 1125 PM until 600 AM CDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2 inches in diameter possible Isolated damaging wind gusts to 65 mph possible SUMMARY...A band of storms with embedded supercell structures is expected to develop/expand eastward through the early morning hours from eastern North Dakota into northern Minnesota. Large hail of 1-2 inches in diameter will be the main threat initially, though there will be some potential for isolated strong-severe outflow gusts up to 65 mph as storm clusters grow overnight. The severe thunderstorm watch area is approximately along and 45 statute miles north and south of a line from 40 miles north northwest of Jamestown ND to 65 miles east of Bemidji MN. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU2). 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 55 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 24035. ...Thompson Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0102 AM CDT Tue Jul 15 2025 Valid 171200Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe potential is low/uncertain on Thursday. ...Discussion... Low-amplitude westerly flow will persist from the northern Rockies to the Great Lakes and Mid-Atlantic on Thursday. Meanwhile, the subtropical upper high over the Southeast will slowly spread westward. At the surface, a cold front will extend from northwest OH to northwest OK and the TX Panhandle at the beginning of the period. Much of the boundary will stall/move very little over the Plains and Mid-MS/Lower OH Valley. Meanwhile, the northern portions of the front will spread east across the Lower Great Lakes and portions of the Northeast. Some severe potential could develop in the vicinity of the surface boundary across the Ohio Valley into the Mid-Atlantic vicinity. However, large disparity exists among forecast guidance with regards to the position of the cold front and any potential MCVs from prior day's convection. This uncertainty precludes severe probabilities at this time, but could become necessary in later outlooks as details become better resolved. ..Leitman.. 07/15/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0102 AM CDT Tue Jul 15 2025 Valid 171200Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe potential is low/uncertain on Thursday. ...Discussion... Low-amplitude westerly flow will persist from the northern Rockies to the Great Lakes and Mid-Atlantic on Thursday. Meanwhile, the subtropical upper high over the Southeast will slowly spread westward. At the surface, a cold front will extend from northwest OH to northwest OK and the TX Panhandle at the beginning of the period. Much of the boundary will stall/move very little over the Plains and Mid-MS/Lower OH Valley. Meanwhile, the northern portions of the front will spread east across the Lower Great Lakes and portions of the Northeast. Some severe potential could develop in the vicinity of the surface boundary across the Ohio Valley into the Mid-Atlantic vicinity. However, large disparity exists among forecast guidance with regards to the position of the cold front and any potential MCVs from prior day's convection. This uncertainty precludes severe probabilities at this time, but could become necessary in later outlooks as details become better resolved. ..Leitman.. 07/15/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0102 AM CDT Tue Jul 15 2025 Valid 171200Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe potential is low/uncertain on Thursday. ...Discussion... Low-amplitude westerly flow will persist from the northern Rockies to the Great Lakes and Mid-Atlantic on Thursday. Meanwhile, the subtropical upper high over the Southeast will slowly spread westward. At the surface, a cold front will extend from northwest OH to northwest OK and the TX Panhandle at the beginning of the period. Much of the boundary will stall/move very little over the Plains and Mid-MS/Lower OH Valley. Meanwhile, the northern portions of the front will spread east across the Lower Great Lakes and portions of the Northeast. Some severe potential could develop in the vicinity of the surface boundary across the Ohio Valley into the Mid-Atlantic vicinity. However, large disparity exists among forecast guidance with regards to the position of the cold front and any potential MCVs from prior day's convection. This uncertainty precludes severe probabilities at this time, but could become necessary in later outlooks as details become better resolved. ..Leitman.. 07/15/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0102 AM CDT Tue Jul 15 2025 Valid 171200Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe potential is low/uncertain on Thursday. ...Discussion... Low-amplitude westerly flow will persist from the northern Rockies to the Great Lakes and Mid-Atlantic on Thursday. Meanwhile, the subtropical upper high over the Southeast will slowly spread westward. At the surface, a cold front will extend from northwest OH to northwest OK and the TX Panhandle at the beginning of the period. Much of the boundary will stall/move very little over the Plains and Mid-MS/Lower OH Valley. Meanwhile, the northern portions of the front will spread east across the Lower Great Lakes and portions of the Northeast. Some severe potential could develop in the vicinity of the surface boundary across the Ohio Valley into the Mid-Atlantic vicinity. However, large disparity exists among forecast guidance with regards to the position of the cold front and any potential MCVs from prior day's convection. This uncertainty precludes severe probabilities at this time, but could become necessary in later outlooks as details become better resolved. ..Leitman.. 07/15/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0102 AM CDT Tue Jul 15 2025 Valid 171200Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe potential is low/uncertain on Thursday. ...Discussion... Low-amplitude westerly flow will persist from the northern Rockies to the Great Lakes and Mid-Atlantic on Thursday. Meanwhile, the subtropical upper high over the Southeast will slowly spread westward. At the surface, a cold front will extend from northwest OH to northwest OK and the TX Panhandle at the beginning of the period. Much of the boundary will stall/move very little over the Plains and Mid-MS/Lower OH Valley. Meanwhile, the northern portions of the front will spread east across the Lower Great Lakes and portions of the Northeast. Some severe potential could develop in the vicinity of the surface boundary across the Ohio Valley into the Mid-Atlantic vicinity. However, large disparity exists among forecast guidance with regards to the position of the cold front and any potential MCVs from prior day's convection. This uncertainty precludes severe probabilities at this time, but could become necessary in later outlooks as details become better resolved. ..Leitman.. 07/15/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0102 AM CDT Tue Jul 15 2025 Valid 171200Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe potential is low/uncertain on Thursday. ...Discussion... Low-amplitude westerly flow will persist from the northern Rockies to the Great Lakes and Mid-Atlantic on Thursday. Meanwhile, the subtropical upper high over the Southeast will slowly spread westward. At the surface, a cold front will extend from northwest OH to northwest OK and the TX Panhandle at the beginning of the period. Much of the boundary will stall/move very little over the Plains and Mid-MS/Lower OH Valley. Meanwhile, the northern portions of the front will spread east across the Lower Great Lakes and portions of the Northeast. Some severe potential could develop in the vicinity of the surface boundary across the Ohio Valley into the Mid-Atlantic vicinity. However, large disparity exists among forecast guidance with regards to the position of the cold front and any potential MCVs from prior day's convection. This uncertainty precludes severe probabilities at this time, but could become necessary in later outlooks as details become better resolved. ..Leitman.. 07/15/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0102 AM CDT Tue Jul 15 2025 Valid 171200Z - 181200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe potential is low/uncertain on Thursday. ...Discussion... Low-amplitude westerly flow will persist from the northern Rockies to the Great Lakes and Mid-Atlantic on Thursday. Meanwhile, the subtropical upper high over the Southeast will slowly spread westward. At the surface, a cold front will extend from northwest OH to northwest OK and the TX Panhandle at the beginning of the period. Much of the boundary will stall/move very little over the Plains and Mid-MS/Lower OH Valley. Meanwhile, the northern portions of the front will spread east across the Lower Great Lakes and portions of the Northeast. Some severe potential could develop in the vicinity of the surface boundary across the Ohio Valley into the Mid-Atlantic vicinity. However, large disparity exists among forecast guidance with regards to the position of the cold front and any potential MCVs from prior day's convection. This uncertainty precludes severe probabilities at this time, but could become necessary in later outlooks as details become better resolved. ..Leitman.. 07/15/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 AM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN IOWA...NORTHERN ILLINOIS...AND SOUTHERN WISCONSIN... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Mid-MS Valley/Great Lakes Vicinity... An upper shortwave trough and MCV is forecast to be located over IA Wednesday morning. Some ongoing convection is possible from MN into IA associated with this feature and attendant outflow. As the MCV shifts east/northeast, a composite outflow/surface cold front located from central WI into eastern IA will develop eastward across portion of northern MO/IL through the evening. The downstream warm sector will be characterized rich moisture, with dewpoints in the 70s F. Daytime heating and modest lapse rates will support strong instability (2000-3000 J/kg MLCAPE). Vertical shear should increase as strengthening midlevel westerlies overspread the region, resulting in 25-35 kt effective shear magnitudes. Organized cells and clusters will pose a risk for damaging gusts. Low-level shear may be somewhat enhanced close to the MCV/surface low across northern IL. Forecast soundings show modestly enlarged/curved hodographs and a tornado or two could also occur. A more marginal severe risk could spread east into portions of Lower MI and northern IN during the late evening/overnight hours, but overall risk should gradually diminish with eastward extent. ...Central Plains Vicinity... The western edge of a southward sagging cold front will move across eastern CO/NE and portions of KS during the day. A very moist and unstable airmass is expected across the region. Vertical shear will remain modest, with stronger midlevel westerlies expected to lag behind the front. Nevertheless, the sagging surface front should provide focus for isolated to scattered thunderstorm development within the warm sector, with an accompanying risk for strong gusts. Additional storms are expected to develop over the central High Plains of southeast WY/eastern CO in the post-frontal upslope regime. This activity will spread eastward during the evening and may be elevated. Isolated hail and strong gusts will be possible initially. While guidance varies considerably, some potential exists for an MCS to develop over parts of KS during the nighttime hours as the front continues to sag southward and a modest low-level jet develops. Given large model spread, will hold off on higher outlook probabilities at this time. ...Upper Ohio Valley... Scattered to numerous thunderstorms are expected across the region i response to a shortwave impulse. While modest instability is forecast amid a very moist airmass, vertical shear will remain weak. Sporadic strong gusts/wet microbursts could occur, but organized severe potential continues to be limited/uncertain. ..Leitman.. 07/15/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 AM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN IOWA...NORTHERN ILLINOIS...AND SOUTHERN WISCONSIN... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Mid-MS Valley/Great Lakes Vicinity... An upper shortwave trough and MCV is forecast to be located over IA Wednesday morning. Some ongoing convection is possible from MN into IA associated with this feature and attendant outflow. As the MCV shifts east/northeast, a composite outflow/surface cold front located from central WI into eastern IA will develop eastward across portion of northern MO/IL through the evening. The downstream warm sector will be characterized rich moisture, with dewpoints in the 70s F. Daytime heating and modest lapse rates will support strong instability (2000-3000 J/kg MLCAPE). Vertical shear should increase as strengthening midlevel westerlies overspread the region, resulting in 25-35 kt effective shear magnitudes. Organized cells and clusters will pose a risk for damaging gusts. Low-level shear may be somewhat enhanced close to the MCV/surface low across northern IL. Forecast soundings show modestly enlarged/curved hodographs and a tornado or two could also occur. A more marginal severe risk could spread east into portions of Lower MI and northern IN during the late evening/overnight hours, but overall risk should gradually diminish with eastward extent. ...Central Plains Vicinity... The western edge of a southward sagging cold front will move across eastern CO/NE and portions of KS during the day. A very moist and unstable airmass is expected across the region. Vertical shear will remain modest, with stronger midlevel westerlies expected to lag behind the front. Nevertheless, the sagging surface front should provide focus for isolated to scattered thunderstorm development within the warm sector, with an accompanying risk for strong gusts. Additional storms are expected to develop over the central High Plains of southeast WY/eastern CO in the post-frontal upslope regime. This activity will spread eastward during the evening and may be elevated. Isolated hail and strong gusts will be possible initially. While guidance varies considerably, some potential exists for an MCS to develop over parts of KS during the nighttime hours as the front continues to sag southward and a modest low-level jet develops. Given large model spread, will hold off on higher outlook probabilities at this time. ...Upper Ohio Valley... Scattered to numerous thunderstorms are expected across the region i response to a shortwave impulse. While modest instability is forecast amid a very moist airmass, vertical shear will remain weak. Sporadic strong gusts/wet microbursts could occur, but organized severe potential continues to be limited/uncertain. ..Leitman.. 07/15/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 AM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN IOWA...NORTHERN ILLINOIS...AND SOUTHERN WISCONSIN... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Mid-MS Valley/Great Lakes Vicinity... An upper shortwave trough and MCV is forecast to be located over IA Wednesday morning. Some ongoing convection is possible from MN into IA associated with this feature and attendant outflow. As the MCV shifts east/northeast, a composite outflow/surface cold front located from central WI into eastern IA will develop eastward across portion of northern MO/IL through the evening. The downstream warm sector will be characterized rich moisture, with dewpoints in the 70s F. Daytime heating and modest lapse rates will support strong instability (2000-3000 J/kg MLCAPE). Vertical shear should increase as strengthening midlevel westerlies overspread the region, resulting in 25-35 kt effective shear magnitudes. Organized cells and clusters will pose a risk for damaging gusts. Low-level shear may be somewhat enhanced close to the MCV/surface low across northern IL. Forecast soundings show modestly enlarged/curved hodographs and a tornado or two could also occur. A more marginal severe risk could spread east into portions of Lower MI and northern IN during the late evening/overnight hours, but overall risk should gradually diminish with eastward extent. ...Central Plains Vicinity... The western edge of a southward sagging cold front will move across eastern CO/NE and portions of KS during the day. A very moist and unstable airmass is expected across the region. Vertical shear will remain modest, with stronger midlevel westerlies expected to lag behind the front. Nevertheless, the sagging surface front should provide focus for isolated to scattered thunderstorm development within the warm sector, with an accompanying risk for strong gusts. Additional storms are expected to develop over the central High Plains of southeast WY/eastern CO in the post-frontal upslope regime. This activity will spread eastward during the evening and may be elevated. Isolated hail and strong gusts will be possible initially. While guidance varies considerably, some potential exists for an MCS to develop over parts of KS during the nighttime hours as the front continues to sag southward and a modest low-level jet develops. Given large model spread, will hold off on higher outlook probabilities at this time. ...Upper Ohio Valley... Scattered to numerous thunderstorms are expected across the region i response to a shortwave impulse. While modest instability is forecast amid a very moist airmass, vertical shear will remain weak. Sporadic strong gusts/wet microbursts could occur, but organized severe potential continues to be limited/uncertain. ..Leitman.. 07/15/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 AM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN IOWA...NORTHERN ILLINOIS...AND SOUTHERN WISCONSIN... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Mid-MS Valley/Great Lakes Vicinity... An upper shortwave trough and MCV is forecast to be located over IA Wednesday morning. Some ongoing convection is possible from MN into IA associated with this feature and attendant outflow. As the MCV shifts east/northeast, a composite outflow/surface cold front located from central WI into eastern IA will develop eastward across portion of northern MO/IL through the evening. The downstream warm sector will be characterized rich moisture, with dewpoints in the 70s F. Daytime heating and modest lapse rates will support strong instability (2000-3000 J/kg MLCAPE). Vertical shear should increase as strengthening midlevel westerlies overspread the region, resulting in 25-35 kt effective shear magnitudes. Organized cells and clusters will pose a risk for damaging gusts. Low-level shear may be somewhat enhanced close to the MCV/surface low across northern IL. Forecast soundings show modestly enlarged/curved hodographs and a tornado or two could also occur. A more marginal severe risk could spread east into portions of Lower MI and northern IN during the late evening/overnight hours, but overall risk should gradually diminish with eastward extent. ...Central Plains Vicinity... The western edge of a southward sagging cold front will move across eastern CO/NE and portions of KS during the day. A very moist and unstable airmass is expected across the region. Vertical shear will remain modest, with stronger midlevel westerlies expected to lag behind the front. Nevertheless, the sagging surface front should provide focus for isolated to scattered thunderstorm development within the warm sector, with an accompanying risk for strong gusts. Additional storms are expected to develop over the central High Plains of southeast WY/eastern CO in the post-frontal upslope regime. This activity will spread eastward during the evening and may be elevated. Isolated hail and strong gusts will be possible initially. While guidance varies considerably, some potential exists for an MCS to develop over parts of KS during the nighttime hours as the front continues to sag southward and a modest low-level jet develops. Given large model spread, will hold off on higher outlook probabilities at this time. ...Upper Ohio Valley... Scattered to numerous thunderstorms are expected across the region i response to a shortwave impulse. While modest instability is forecast amid a very moist airmass, vertical shear will remain weak. Sporadic strong gusts/wet microbursts could occur, but organized severe potential continues to be limited/uncertain. ..Leitman.. 07/15/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 AM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN IOWA...NORTHERN ILLINOIS...AND SOUTHERN WISCONSIN... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Mid-MS Valley/Great Lakes Vicinity... An upper shortwave trough and MCV is forecast to be located over IA Wednesday morning. Some ongoing convection is possible from MN into IA associated with this feature and attendant outflow. As the MCV shifts east/northeast, a composite outflow/surface cold front located from central WI into eastern IA will develop eastward across portion of northern MO/IL through the evening. The downstream warm sector will be characterized rich moisture, with dewpoints in the 70s F. Daytime heating and modest lapse rates will support strong instability (2000-3000 J/kg MLCAPE). Vertical shear should increase as strengthening midlevel westerlies overspread the region, resulting in 25-35 kt effective shear magnitudes. Organized cells and clusters will pose a risk for damaging gusts. Low-level shear may be somewhat enhanced close to the MCV/surface low across northern IL. Forecast soundings show modestly enlarged/curved hodographs and a tornado or two could also occur. A more marginal severe risk could spread east into portions of Lower MI and northern IN during the late evening/overnight hours, but overall risk should gradually diminish with eastward extent. ...Central Plains Vicinity... The western edge of a southward sagging cold front will move across eastern CO/NE and portions of KS during the day. A very moist and unstable airmass is expected across the region. Vertical shear will remain modest, with stronger midlevel westerlies expected to lag behind the front. Nevertheless, the sagging surface front should provide focus for isolated to scattered thunderstorm development within the warm sector, with an accompanying risk for strong gusts. Additional storms are expected to develop over the central High Plains of southeast WY/eastern CO in the post-frontal upslope regime. This activity will spread eastward during the evening and may be elevated. Isolated hail and strong gusts will be possible initially. While guidance varies considerably, some potential exists for an MCS to develop over parts of KS during the nighttime hours as the front continues to sag southward and a modest low-level jet develops. Given large model spread, will hold off on higher outlook probabilities at this time. ...Upper Ohio Valley... Scattered to numerous thunderstorms are expected across the region i response to a shortwave impulse. While modest instability is forecast amid a very moist airmass, vertical shear will remain weak. Sporadic strong gusts/wet microbursts could occur, but organized severe potential continues to be limited/uncertain. ..Leitman.. 07/15/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 AM CDT Tue Jul 15 2025 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN IOWA...NORTHERN ILLINOIS...AND SOUTHERN WISCONSIN... ...SUMMARY... Scattered strong to severe thunderstorms are possible Wednesday afternoon and evening from parts of the central High Plains to the Great Lakes. ...Mid-MS Valley/Great Lakes Vicinity... An upper shortwave trough and MCV is forecast to be located over IA Wednesday morning. Some ongoing convection is possible from MN into IA associated with this feature and attendant outflow. As the MCV shifts east/northeast, a composite outflow/surface cold front located from central WI into eastern IA will develop eastward across portion of northern MO/IL through the evening. The downstream warm sector will be characterized rich moisture, with dewpoints in the 70s F. Daytime heating and modest lapse rates will support strong instability (2000-3000 J/kg MLCAPE). Vertical shear should increase as strengthening midlevel westerlies overspread the region, resulting in 25-35 kt effective shear magnitudes. Organized cells and clusters will pose a risk for damaging gusts. Low-level shear may be somewhat enhanced close to the MCV/surface low across northern IL. Forecast soundings show modestly enlarged/curved hodographs and a tornado or two could also occur. A more marginal severe risk could spread east into portions of Lower MI and northern IN during the late evening/overnight hours, but overall risk should gradually diminish with eastward extent. ...Central Plains Vicinity... The western edge of a southward sagging cold front will move across eastern CO/NE and portions of KS during the day. A very moist and unstable airmass is expected across the region. Vertical shear will remain modest, with stronger midlevel westerlies expected to lag behind the front. Nevertheless, the sagging surface front should provide focus for isolated to scattered thunderstorm development within the warm sector, with an accompanying risk for strong gusts. Additional storms are expected to develop over the central High Plains of southeast WY/eastern CO in the post-frontal upslope regime. This activity will spread eastward during the evening and may be elevated. Isolated hail and strong gusts will be possible initially. While guidance varies considerably, some potential exists for an MCS to develop over parts of KS during the nighttime hours as the front continues to sag southward and a modest low-level jet develops. Given large model spread, will hold off on higher outlook probabilities at this time. ...Upper Ohio Valley... Scattered to numerous thunderstorms are expected across the region i response to a shortwave impulse. While modest instability is forecast amid a very moist airmass, vertical shear will remain weak. Sporadic strong gusts/wet microbursts could occur, but organized severe potential continues to be limited/uncertain. ..Leitman.. 07/15/2025 Read more