Severe Storms

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0759 PM CDT Fri Aug 15 2025 Valid 160100Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO THE OVERNIGHT HOURS ACROSS PARTS OF CENTRAL AND EASTERN SOUTH DAKOTA...NORTHERN NEBRASKA...SOUTHWESTERN MINNESOTA...NORTHWESTERN IOWA...PARTS OF SOUTHEASTERN IOWA AND SOUTHWESTERN WISCONSIN... ...SUMMARY... An organizing cluster of thunderstorms with potential to produce strong to severe wind gusts may still evolve later this evening into the overnight hours across parts of the middle Missouri Valley and adjacent Great Plains. ...01Z Update... Stronger westerlies remain generally confined to the higher latitudes, near/north of the Canadian/U.S. border. To the southwest of one significant embedded short wave trough crossing the Hudson Bay and northern Ontario vicinity, modest westerly mid-level flow (including speeds of 30-40 kt around 500 mb) is overspreading areas as far south as the Dakotas into Upper Midwest, near the northern periphery of mid-level ridging. Forcing associated with subtle perturbations embedded within this regime has contributed to several developing clusters of storms. A couple now propagating east of the upper Mississippi Valley appear to be in the process of weakening, likely due to some combination of weak/weakening lift and increasing inhibition beneath relatively warm mid-level temperatures encompassing much of the northern and central Great Plains into Midwest. Beneath steeper mid-level lapse rates upstream, boundary-layer moisture east of the lee surface trough across the high plains is still contributing to strong to extreme potential instability across much of central and eastern South Dakota/Nebraska, as scattered high based convection emerges from eastern Wyoming and northeastern Colorado. It appears possible that low-level forcing for ascent, near the nose of a nocturnally strengthening southerly low-level jet, could contribute to a consolidating and upscale growing cluster, particularly as activity acquires more unstable inflow later this evening into the overnight. Various model output, including the NAM and Rapid Refresh, suggest that the evolution of a notable convective perturbation is possible, which could be accompanied by a swath of strong to severe wind gusts. ..Kerr.. 08/16/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0759 PM CDT Fri Aug 15 2025 Valid 160100Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO THE OVERNIGHT HOURS ACROSS PARTS OF CENTRAL AND EASTERN SOUTH DAKOTA...NORTHERN NEBRASKA...SOUTHWESTERN MINNESOTA...NORTHWESTERN IOWA...PARTS OF SOUTHEASTERN IOWA AND SOUTHWESTERN WISCONSIN... ...SUMMARY... An organizing cluster of thunderstorms with potential to produce strong to severe wind gusts may still evolve later this evening into the overnight hours across parts of the middle Missouri Valley and adjacent Great Plains. ...01Z Update... Stronger westerlies remain generally confined to the higher latitudes, near/north of the Canadian/U.S. border. To the southwest of one significant embedded short wave trough crossing the Hudson Bay and northern Ontario vicinity, modest westerly mid-level flow (including speeds of 30-40 kt around 500 mb) is overspreading areas as far south as the Dakotas into Upper Midwest, near the northern periphery of mid-level ridging. Forcing associated with subtle perturbations embedded within this regime has contributed to several developing clusters of storms. A couple now propagating east of the upper Mississippi Valley appear to be in the process of weakening, likely due to some combination of weak/weakening lift and increasing inhibition beneath relatively warm mid-level temperatures encompassing much of the northern and central Great Plains into Midwest. Beneath steeper mid-level lapse rates upstream, boundary-layer moisture east of the lee surface trough across the high plains is still contributing to strong to extreme potential instability across much of central and eastern South Dakota/Nebraska, as scattered high based convection emerges from eastern Wyoming and northeastern Colorado. It appears possible that low-level forcing for ascent, near the nose of a nocturnally strengthening southerly low-level jet, could contribute to a consolidating and upscale growing cluster, particularly as activity acquires more unstable inflow later this evening into the overnight. Various model output, including the NAM and Rapid Refresh, suggest that the evolution of a notable convective perturbation is possible, which could be accompanied by a swath of strong to severe wind gusts. ..Kerr.. 08/16/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0759 PM CDT Fri Aug 15 2025 Valid 160100Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO THE OVERNIGHT HOURS ACROSS PARTS OF CENTRAL AND EASTERN SOUTH DAKOTA...NORTHERN NEBRASKA...SOUTHWESTERN MINNESOTA...NORTHWESTERN IOWA...PARTS OF SOUTHEASTERN IOWA AND SOUTHWESTERN WISCONSIN... ...SUMMARY... An organizing cluster of thunderstorms with potential to produce strong to severe wind gusts may still evolve later this evening into the overnight hours across parts of the middle Missouri Valley and adjacent Great Plains. ...01Z Update... Stronger westerlies remain generally confined to the higher latitudes, near/north of the Canadian/U.S. border. To the southwest of one significant embedded short wave trough crossing the Hudson Bay and northern Ontario vicinity, modest westerly mid-level flow (including speeds of 30-40 kt around 500 mb) is overspreading areas as far south as the Dakotas into Upper Midwest, near the northern periphery of mid-level ridging. Forcing associated with subtle perturbations embedded within this regime has contributed to several developing clusters of storms. A couple now propagating east of the upper Mississippi Valley appear to be in the process of weakening, likely due to some combination of weak/weakening lift and increasing inhibition beneath relatively warm mid-level temperatures encompassing much of the northern and central Great Plains into Midwest. Beneath steeper mid-level lapse rates upstream, boundary-layer moisture east of the lee surface trough across the high plains is still contributing to strong to extreme potential instability across much of central and eastern South Dakota/Nebraska, as scattered high based convection emerges from eastern Wyoming and northeastern Colorado. It appears possible that low-level forcing for ascent, near the nose of a nocturnally strengthening southerly low-level jet, could contribute to a consolidating and upscale growing cluster, particularly as activity acquires more unstable inflow later this evening into the overnight. Various model output, including the NAM and Rapid Refresh, suggest that the evolution of a notable convective perturbation is possible, which could be accompanied by a swath of strong to severe wind gusts. ..Kerr.. 08/16/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0759 PM CDT Fri Aug 15 2025 Valid 160100Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO THE OVERNIGHT HOURS ACROSS PARTS OF CENTRAL AND EASTERN SOUTH DAKOTA...NORTHERN NEBRASKA...SOUTHWESTERN MINNESOTA...NORTHWESTERN IOWA...PARTS OF SOUTHEASTERN IOWA AND SOUTHWESTERN WISCONSIN... ...SUMMARY... An organizing cluster of thunderstorms with potential to produce strong to severe wind gusts may still evolve later this evening into the overnight hours across parts of the middle Missouri Valley and adjacent Great Plains. ...01Z Update... Stronger westerlies remain generally confined to the higher latitudes, near/north of the Canadian/U.S. border. To the southwest of one significant embedded short wave trough crossing the Hudson Bay and northern Ontario vicinity, modest westerly mid-level flow (including speeds of 30-40 kt around 500 mb) is overspreading areas as far south as the Dakotas into Upper Midwest, near the northern periphery of mid-level ridging. Forcing associated with subtle perturbations embedded within this regime has contributed to several developing clusters of storms. A couple now propagating east of the upper Mississippi Valley appear to be in the process of weakening, likely due to some combination of weak/weakening lift and increasing inhibition beneath relatively warm mid-level temperatures encompassing much of the northern and central Great Plains into Midwest. Beneath steeper mid-level lapse rates upstream, boundary-layer moisture east of the lee surface trough across the high plains is still contributing to strong to extreme potential instability across much of central and eastern South Dakota/Nebraska, as scattered high based convection emerges from eastern Wyoming and northeastern Colorado. It appears possible that low-level forcing for ascent, near the nose of a nocturnally strengthening southerly low-level jet, could contribute to a consolidating and upscale growing cluster, particularly as activity acquires more unstable inflow later this evening into the overnight. Various model output, including the NAM and Rapid Refresh, suggest that the evolution of a notable convective perturbation is possible, which could be accompanied by a swath of strong to severe wind gusts. ..Kerr.. 08/16/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0759 PM CDT Fri Aug 15 2025 Valid 160100Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO THE OVERNIGHT HOURS ACROSS PARTS OF CENTRAL AND EASTERN SOUTH DAKOTA...NORTHERN NEBRASKA...SOUTHWESTERN MINNESOTA...NORTHWESTERN IOWA...PARTS OF SOUTHEASTERN IOWA AND SOUTHWESTERN WISCONSIN... ...SUMMARY... An organizing cluster of thunderstorms with potential to produce strong to severe wind gusts may still evolve later this evening into the overnight hours across parts of the middle Missouri Valley and adjacent Great Plains. ...01Z Update... Stronger westerlies remain generally confined to the higher latitudes, near/north of the Canadian/U.S. border. To the southwest of one significant embedded short wave trough crossing the Hudson Bay and northern Ontario vicinity, modest westerly mid-level flow (including speeds of 30-40 kt around 500 mb) is overspreading areas as far south as the Dakotas into Upper Midwest, near the northern periphery of mid-level ridging. Forcing associated with subtle perturbations embedded within this regime has contributed to several developing clusters of storms. A couple now propagating east of the upper Mississippi Valley appear to be in the process of weakening, likely due to some combination of weak/weakening lift and increasing inhibition beneath relatively warm mid-level temperatures encompassing much of the northern and central Great Plains into Midwest. Beneath steeper mid-level lapse rates upstream, boundary-layer moisture east of the lee surface trough across the high plains is still contributing to strong to extreme potential instability across much of central and eastern South Dakota/Nebraska, as scattered high based convection emerges from eastern Wyoming and northeastern Colorado. It appears possible that low-level forcing for ascent, near the nose of a nocturnally strengthening southerly low-level jet, could contribute to a consolidating and upscale growing cluster, particularly as activity acquires more unstable inflow later this evening into the overnight. Various model output, including the NAM and Rapid Refresh, suggest that the evolution of a notable convective perturbation is possible, which could be accompanied by a swath of strong to severe wind gusts. ..Kerr.. 08/16/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0759 PM CDT Fri Aug 15 2025 Valid 160100Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO THE OVERNIGHT HOURS ACROSS PARTS OF CENTRAL AND EASTERN SOUTH DAKOTA...NORTHERN NEBRASKA...SOUTHWESTERN MINNESOTA...NORTHWESTERN IOWA...PARTS OF SOUTHEASTERN IOWA AND SOUTHWESTERN WISCONSIN... ...SUMMARY... An organizing cluster of thunderstorms with potential to produce strong to severe wind gusts may still evolve later this evening into the overnight hours across parts of the middle Missouri Valley and adjacent Great Plains. ...01Z Update... Stronger westerlies remain generally confined to the higher latitudes, near/north of the Canadian/U.S. border. To the southwest of one significant embedded short wave trough crossing the Hudson Bay and northern Ontario vicinity, modest westerly mid-level flow (including speeds of 30-40 kt around 500 mb) is overspreading areas as far south as the Dakotas into Upper Midwest, near the northern periphery of mid-level ridging. Forcing associated with subtle perturbations embedded within this regime has contributed to several developing clusters of storms. A couple now propagating east of the upper Mississippi Valley appear to be in the process of weakening, likely due to some combination of weak/weakening lift and increasing inhibition beneath relatively warm mid-level temperatures encompassing much of the northern and central Great Plains into Midwest. Beneath steeper mid-level lapse rates upstream, boundary-layer moisture east of the lee surface trough across the high plains is still contributing to strong to extreme potential instability across much of central and eastern South Dakota/Nebraska, as scattered high based convection emerges from eastern Wyoming and northeastern Colorado. It appears possible that low-level forcing for ascent, near the nose of a nocturnally strengthening southerly low-level jet, could contribute to a consolidating and upscale growing cluster, particularly as activity acquires more unstable inflow later this evening into the overnight. Various model output, including the NAM and Rapid Refresh, suggest that the evolution of a notable convective perturbation is possible, which could be accompanied by a swath of strong to severe wind gusts. ..Kerr.. 08/16/2025 Read more

WW 0590 Status Updates
STATUS REPORT ON WW 590 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 NNW ALO TO 40 SE RST. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1953. ..GRAMS..08/15/25 ATTN...WFO...ARX...DVN... STATUS REPORT FOR WS 590 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC015-073-085-131-161-195-152140- IL . ILLINOIS COUNTIES INCLUDED ARE CARROLL HENRY JO DAVIESS MERCER ROCK ISLAND WHITESIDE IAC005-011-019-031-037-043-045-055-061-065-095-097-103-105-107- 113-115-139-163-183-191-152140- IA . IOWA COUNTIES INCLUDED ARE ALLAMAKEE BENTON BUCHANAN CEDAR CHICKASAW CLAYTON CLINTON DELAWARE DUBUQUE FAYETTE IOWA JACKSON JOHNSON JONES KEOKUK LINN LOUISA MUSCATINE SCOTT WASHINGTON WINNESHIEK Read more

WW 0590 Status Updates
STATUS REPORT ON WW 590 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 NNW ALO TO 40 SE RST. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1953. ..GRAMS..08/15/25 ATTN...WFO...ARX...DVN... STATUS REPORT FOR WS 590 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC015-073-085-131-161-195-152140- IL . ILLINOIS COUNTIES INCLUDED ARE CARROLL HENRY JO DAVIESS MERCER ROCK ISLAND WHITESIDE IAC005-011-019-031-037-043-045-055-061-065-095-097-103-105-107- 113-115-139-163-183-191-152140- IA . IOWA COUNTIES INCLUDED ARE ALLAMAKEE BENTON BUCHANAN CEDAR CHICKASAW CLAYTON CLINTON DELAWARE DUBUQUE FAYETTE IOWA JACKSON JOHNSON JONES KEOKUK LINN LOUISA MUSCATINE SCOTT WASHINGTON WINNESHIEK Read more

WW 0590 Status Updates
STATUS REPORT ON WW 590 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 NNW ALO TO 40 SE RST. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1953. ..GRAMS..08/15/25 ATTN...WFO...ARX...DVN... STATUS REPORT FOR WS 590 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC015-073-085-131-161-195-152140- IL . ILLINOIS COUNTIES INCLUDED ARE CARROLL HENRY JO DAVIESS MERCER ROCK ISLAND WHITESIDE IAC005-011-019-031-037-043-045-055-061-065-095-097-103-105-107- 113-115-139-163-183-191-152140- IA . IOWA COUNTIES INCLUDED ARE ALLAMAKEE BENTON BUCHANAN CEDAR CHICKASAW CLAYTON CLINTON DELAWARE DUBUQUE FAYETTE IOWA JACKSON JOHNSON JONES KEOKUK LINN LOUISA MUSCATINE SCOTT WASHINGTON WINNESHIEK Read more

WW 0590 Status Updates
STATUS REPORT ON WW 590 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 NNW ALO TO 40 SE RST. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1953. ..GRAMS..08/15/25 ATTN...WFO...ARX...DVN... STATUS REPORT FOR WS 590 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC015-073-085-131-161-195-152140- IL . ILLINOIS COUNTIES INCLUDED ARE CARROLL HENRY JO DAVIESS MERCER ROCK ISLAND WHITESIDE IAC005-011-019-031-037-043-045-055-061-065-095-097-103-105-107- 113-115-139-163-183-191-152140- IA . IOWA COUNTIES INCLUDED ARE ALLAMAKEE BENTON BUCHANAN CEDAR CHICKASAW CLAYTON CLINTON DELAWARE DUBUQUE FAYETTE IOWA JACKSON JOHNSON JONES KEOKUK LINN LOUISA MUSCATINE SCOTT WASHINGTON WINNESHIEK Read more

WW 0590 Status Updates
STATUS REPORT ON WW 590 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 NNW ALO TO 40 SE RST. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1953. ..GRAMS..08/15/25 ATTN...WFO...ARX...DVN... STATUS REPORT FOR WS 590 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC015-073-085-131-161-195-152140- IL . ILLINOIS COUNTIES INCLUDED ARE CARROLL HENRY JO DAVIESS MERCER ROCK ISLAND WHITESIDE IAC005-011-019-031-037-043-045-055-061-065-095-097-103-105-107- 113-115-139-163-183-191-152140- IA . IOWA COUNTIES INCLUDED ARE ALLAMAKEE BENTON BUCHANAN CEDAR CHICKASAW CLAYTON CLINTON DELAWARE DUBUQUE FAYETTE IOWA JACKSON JOHNSON JONES KEOKUK LINN LOUISA MUSCATINE SCOTT WASHINGTON WINNESHIEK Read more

MD 1956 CONCERNING SEVERE THUNDERSTORM WATCH 590... FOR PORTIONS OF EASTERN/SOUTHEASTERN IOWA INTO NORTHWESTERN ILLINOIS
Mesoscale Discussion 1956 NWS Storm Prediction Center Norman OK 0552 PM CDT Fri Aug 15 2025 Areas affected...portions of eastern/southeastern Iowa into northwestern Illinois Concerning...Severe Thunderstorm Watch 590... Valid 152252Z - 160015Z The severe weather threat for Severe Thunderstorm Watch 590 continues. SUMMARY...A well organized bowing cluster should continue across southeastern IA into northwestern IL this evening. Damaging gusts (some 70+ mph) are likely. DISCUSSION...As of 2245 UTC, regional radar imagery shows a stronger bowing cluster has emerged from the initial convection of storms over eastern IA. Downstream, a very unstable environment (4000-5000 J/kg of SBCAPE) remains in place. While vertical shear (25-35 kt) is expected to decrease with southern extent, evidence of an elevated rear-inflow jet and a 20-25 deg F cold pool, along with the degree of buoyancy suggest maintenance of this complex is likely for at least a few more hours. With several gusts to 70+ mph observed over the 60 minutes, damaging winds remain likely across eastern/southeastern IA, into northwestern and possible north-central IL this evening. CAM guidance has not handled the convective evolution particularity well thus far, with only a few outlier solutions capturing the intensity of the bow. This lends lower confidence to the downstream severe risk this evening. However, the continued favorable environment and well-organized radar presentation of the system does suggest at least some damaging wind potential may occur downstream of the eastern edge of WW590 in IL tonight. Conditions will continue to be monitored should an additional watch be needed later this evening. ..Lyons.. 08/15/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...ILX...MKX...DVN...ARX...DMX... LAT...LON 42319219 42829123 42689053 42428952 42228929 41438913 40788942 40379060 40859212 41289261 41679301 41939305 42319219 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

WW 590 SEVERE TSTM IA IL WI 151915Z - 160000Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 590 NWS Storm Prediction Center Norman OK 215 PM CDT Fri Aug 15 2025 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Eastern Iowa Far Northwest Illinois Extreme Southwest Wisconsin * Effective this Friday afternoon and evening from 215 PM until 700 PM CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Convective line currently moving through north-central IA is forecast to continue eastward into eastern IA and adjacent extreme southwest WI and far northwest IL. The airmass in these areas is moist, unstable, and supportive of both isolated large hail and scattered damaging gusts. The severe thunderstorm watch area is approximately along and 55 statute miles east and west of a line from 70 miles north northeast of Waterloo IA to 25 miles west southwest of Moline IL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0). 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. && OTHER WATCH INFORMATION...CONTINUE...WW 589... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 28035. ...Mosier Read more

WW 0591 Status Updates
STATUS FOR WATCH 0591 HAS NOT BEEN ISSUED YET Read more

WW 0592 Status Updates
STATUS FOR WATCH 0592 HAS NOT BEEN ISSUED YET Read more

WW 0592 Status Updates
STATUS FOR WATCH 0592 HAS NOT BEEN ISSUED YET Read more

WW 592 SEVERE TSTM IL 152345Z - 160400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 592 NWS Storm Prediction Center Norman OK 645 PM CDT Fri Aug 15 2025 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northern Illinois * Effective this Friday evening from 645 PM until 1100 PM CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1 inch in diameter possible SUMMARY...A well-organized cluster of storms with a history of 70+ mph wind gusts across eastern Iowa will continue southeastward into northern Illinois. Even with a weakening trend over time, damaging winds will remain a possibility, and perhaps some hail. The severe thunderstorm watch area is approximately along and 50 statute miles north and south of a line from 5 miles west northwest of Moline IL to 75 miles east of Moline IL. 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. && OTHER WATCH INFORMATION...CONTINUE...WW 590...WW 591... AVIATION...A few severe thunderstorms with hail surface and aloft to 1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 30040. ...Guyer Read more

MD 1956 CONCERNING SEVERE THUNDERSTORM WATCH 590... FOR PORTIONS OF EASTERN/SOUTHEASTERN IOWA INTO NORTHWESTERN ILLINOIS
Mesoscale Discussion 1956 NWS Storm Prediction Center Norman OK 0552 PM CDT Fri Aug 15 2025 Areas affected...portions of eastern/southeastern Iowa into northwestern Illinois Concerning...Severe Thunderstorm Watch 590... Valid 152252Z - 160015Z The severe weather threat for Severe Thunderstorm Watch 590 continues. SUMMARY...A well organized bowing cluster should continue across southeastern IA into northwestern IL this evening. Damaging gusts (some 70+ mph) are likely. DISCUSSION...As of 2245 UTC, regional radar imagery shows a stronger bowing cluster has emerged from the initial convection of storms over eastern IA. Downstream, a very unstable environment (4000-5000 J/kg of SBCAPE) remains in place. While vertical shear (25-35 kt) is expected to decrease with southern extent, evidence of an elevated rear-inflow jet and a 20-25 deg F cold pool, along with the degree of buoyancy suggest maintenance of this complex is likely for at least a few more hours. With several gusts to 70+ mph observed over the 60 minutes, damaging winds remain likely across eastern/southeastern IA, into northwestern and possible north-central IL this evening. CAM guidance has not handled the convective evolution particularity well thus far, with only a few outlier solutions capturing the intensity of the bow. This lends lower confidence to the downstream severe risk this evening. However, the continued favorable environment and well-organized radar presentation of the system does suggest at least some damaging wind potential may occur downstream of the eastern edge of WW590 in IL tonight. Conditions will continue to be monitored should an additional watch be needed later this evening. ..Lyons.. 08/15/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...ILX...MKX...DVN...ARX...DMX... LAT...LON 42319219 42829123 42689053 42428952 42228929 41438913 40788942 40379060 40859212 41289261 41679301 41939305 42319219 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

MD 1955 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF EAST-CENTRAL MINNESOTA INTO WESTERN WISCONSIN
Mesoscale Discussion 1955 NWS Storm Prediction Center Norman OK 0458 PM CDT Fri Aug 15 2025 Areas affected...portions of east-central Minnesota into western Wisconsin Concerning...Severe potential...Watch possible Valid 152158Z - 152330Z Probability of Watch Issuance...40 percent SUMMARY...Scattered strong to severe storms, including a few supercells are possible late this afternoon and evening across eastern MN and western WI. Damaging gusts and hail are the most likely hazards. DISCUSSION...As of 2145 UTC, regional observations showed new convective development was ongoing along a modifying frontal boundary across portions of east-central MN. Despite lingering cloud cover from a cluster of storms farther south over IA, sufficiently low-level warming has taken place from low-level warm air advection to allow for scattered thunderstorms in the vicinity of the Twin Cities Metro. Continued storm development/intensification along and south of the boundary appears likely this evening with 70s F surface dewpoints in place. 2000-3000 J/kg of MLCAPE and 35-50 kt of deep-layer shear should support storm organization with a few supercells or short-line segments/clusters evolving with time. Damaging winds are the most likely threat with some potential for storm clustering. While mid-level lapse rates are not overly steep, the moderate to large buoyancy and veering wind profiles could support some hail with any rotating storms. As storms continue to evolve, some back building along the boundary may occur into central MN. Additional development may also merge with the cluster from northern IA into southern MN as indicted by some CAMs. While exact storm evolution remains somewhat unclear owing to the cloud cover and influences from the southern cluster, the overall environment appear supportive of damaging gusts, some hail and possibly a tornado. Given this, conditions are being monitored for a possible WW. ..Lyons/Guyer.. 08/15/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GRB...MKX...DLH...ARX...MPX... LAT...LON 43799121 44019409 45029555 45709534 46339200 46319091 46179000 45958943 45398870 44738871 43988931 43799121 MOST PROBABLE PEAK TORNADO INTENSITY...85-115 MPH MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN Read more

MD 1954 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL HIGH PLAINS
Mesoscale Discussion 1954 NWS Storm Prediction Center Norman OK 0349 PM CDT Fri Aug 15 2025 Areas affected...Central High Plains Concerning...Severe potential...Watch unlikely Valid 152049Z - 152245Z Probability of Watch Issuance...20 percent SUMMARY...Isolated severe winds and large hail will be possible with storms that can move off the terrain into the High Plains. A watch is not expected in the short term. DISCUSSION...Mid-level ascent is evident on visible/water vapor imagery this afternoon from the eastern Great Basin into the central High Plains. Modest moisture (upper 40s/low 50s F) in eastern Wyoming has allowed convection and widely scattered thunderstorms to develop. Inhibition immediately to the east of this activity is slowly weakening. Some this activity will likely move off the terrain. Isolated severe wind gusts and large hail would be possible. The observed 18Z UNR/LBF soundings do show stronger inhibition into the Plains. While there is a signal in guidance for convection to cluster and eventually intensify, this is not likely to occur until early evening when MLCIN erodes farther east. At that point, the low-level jet will focus in the region and mid-level ascent will be marginally stronger. That said, a watch is not anticipated in the short term. ..Wendt/Mosier.. 08/15/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LBF...UNR...BOU...CYS... LAT...LON 40930472 42240527 43610539 44230503 44200432 42610305 41490258 40550269 40080307 39970351 40090422 40930472 MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN Read more