Storm Prediction Center

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 1149 AM CDT Mon Jul 27 2026 Valid 271630Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MIDWEST... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE CENTRAL HIGH PLAINS... CORRECTED FOR THUNDERSTORM LINES ...SUMMARY... Severe storms capable of strong to severe wind gusts and large hail are expected across the Great Lakes and Midwest through tonight. More sporadic occurrences of damaging wind are possible in the Mid-Atlantic, Tennessee Valley, central High Plains, and southeast Arizona. ...Midwest/Ohio Valley... A large upper ridge remains present today over the central Plains/Rockies, with moderately strong northwest flow aloft from the Midwest into the OH Valley. A very moist and unstable low-level air mass resides from WI/IL into MI/IN/OH, where mostly clear skies will result in hot afternoon temperatures and MLCAPE values over 3000 J/kg. Multiple clusters of intense thunderstorms are ongoing over parts of WI tracking southeastward. These storms will move through this reservoir of high CAPE, leading to the potential for an active severe weather event today. However, details of how these clusters evolve are uncertain. Vertical shear across this region will support supercell structures, capable of damaging winds, hail, and isolated tornadoes this afternoon. However, the greater concern is if storms can congeal into a southeastward bowing system and that sweeps across Lower MI, eastern IL, IN, and western OH. Several morning CAM solutions indicate that risk, with storms spreading into KY overnight before weakening. Unfortunately, this synoptic pattern does not lend itself to a high-confidence convective forecast. ...High Plains... Widespread clouds are affecting parts of western NE this morning. However, strong heating will occur north and south of these clouds, leading to afternoon thunderstorms. The most active area will likely be over the Black Hills region where damaging winds and hail are possible. Farther south, widely scattered high-based thunderstorms will affect eastern CO/western KS with a risk of damaging wind gusts. ..Hart/Moore.. 07/27/2026 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1146 AM CDT Mon Jul 27 2026 Valid 271700Z - 281200Z The forecast remains on track for elevated fire weather conditions across portions of the northwestern CONUS. Poor to marginal overnight humidity recoveries and daytime heating will contribute to critical RH values of 10-15% this afternoon amid southwesterly winds of 10-15 mph (gusts up to 25 mph). Meteorological conditions will overlap a very dry, drought-stressed fuelscape (80-95th percentile ERCs) with multiple ongoing large wildfires. Any lightning holdovers from thunderstorms last week/weekend may also emerge as a result of hot, dry, and breezy conditions. ..Elizalde-Garcia.. 07/27/2026 .PREV DISCUSSION... /ISSUED 1124 PM CDT Sun Jul 26 2026/ ...Synopsis... An upper ridge will remain in place over the western CONUS today, with modest mid-level flow poised to pivot around the ridge during the afternoon hours, when a deep and dry boundary layer will encourage downward momentum transport of the stronger flow aloft. The most likely location for boundary-layer mixing and associated stronger surface winds will be across the northern Sierra into the northern Rockies, where southwesterly surface winds may occasionally exceed 15 mph amid 20 percent RH and dry fuels. As such, Elevated highlights have been maintained. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1146 AM CDT Mon Jul 27 2026 Valid 271700Z - 281200Z The forecast remains on track for elevated fire weather conditions across portions of the northwestern CONUS. Poor to marginal overnight humidity recoveries and daytime heating will contribute to critical RH values of 10-15% this afternoon amid southwesterly winds of 10-15 mph (gusts up to 25 mph). Meteorological conditions will overlap a very dry, drought-stressed fuelscape (80-95th percentile ERCs) with multiple ongoing large wildfires. Any lightning holdovers from thunderstorms last week/weekend may also emerge as a result of hot, dry, and breezy conditions. ..Elizalde-Garcia.. 07/27/2026 .PREV DISCUSSION... /ISSUED 1124 PM CDT Sun Jul 26 2026/ ...Synopsis... An upper ridge will remain in place over the western CONUS today, with modest mid-level flow poised to pivot around the ridge during the afternoon hours, when a deep and dry boundary layer will encourage downward momentum transport of the stronger flow aloft. The most likely location for boundary-layer mixing and associated stronger surface winds will be across the northern Sierra into the northern Rockies, where southwesterly surface winds may occasionally exceed 15 mph amid 20 percent RH and dry fuels. As such, Elevated highlights have been maintained. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0519 Status Updates
STATUS REPORT ON WW 519 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 10 ESE AUW TO 25 NNE GRB TO 50 WNW TVC. ..LEITMAN..07/27/26 ATTN...WFO...MQT...GRB... STATUS REPORT FOR WS 519 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS WIC009-015-061-071-087-115-271740- WI . WISCONSIN COUNTIES INCLUDED ARE BROWN CALUMET KEWAUNEE MANITOWOC OUTAGAMIE SHAWANO LMZ522-541-542-543-563-565-567-271740- CW . ADJACENT COASTAL WATERS INCLUDED ARE GREEN BAY SOUTH OF LINE FROM OCONTO WI TO LITTLE STURGEON BAY WI ROCK ISLAND PASSAGE TO STURGEON BAY WI STURGEON BAY TO TWO RIVERS WI TWO RIVERS TO SHEBOYGAN WI LAKE MICHIGAN FROM ROCK ISLAND PASSAGE TO STURGEON BAY WI 5NM OFFSHORE TO MID LAKE Read more

WW 0519 Status Updates
STATUS REPORT ON WW 519 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 10 ESE AUW TO 25 NNE GRB TO 50 WNW TVC. ..LEITMAN..07/27/26 ATTN...WFO...MQT...GRB... STATUS REPORT FOR WS 519 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS WIC009-015-061-071-087-115-271740- WI . WISCONSIN COUNTIES INCLUDED ARE BROWN CALUMET KEWAUNEE MANITOWOC OUTAGAMIE SHAWANO LMZ522-541-542-543-563-565-567-271740- CW . ADJACENT COASTAL WATERS INCLUDED ARE GREEN BAY SOUTH OF LINE FROM OCONTO WI TO LITTLE STURGEON BAY WI ROCK ISLAND PASSAGE TO STURGEON BAY WI STURGEON BAY TO TWO RIVERS WI TWO RIVERS TO SHEBOYGAN WI LAKE MICHIGAN FROM ROCK ISLAND PASSAGE TO STURGEON BAY WI 5NM OFFSHORE TO MID LAKE Read more

WW 519 SEVERE TSTM MI WI LM 271340Z - 272000Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 519 NWS Storm Prediction Center Norman OK 840 AM CDT Mon Jul 27 2026 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Western Upper Michigan Northeast Wisconsin Lake Michigan * Effective this Monday morning and afternoon from 840 AM until 300 PM CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Scattered large hail events to 1.5 inches in diameter possible SUMMARY...A cluster of intense thunderstorms along the Wisconsin/Michigan border will track southeastward through the late morning, posing a risk of damaging winds and hail. The severe thunderstorm watch area is approximately along and 55 statute miles east and west of a line from 55 miles north northeast of Rhinelander WI to 20 miles east southeast of Manitowoc WI. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU9). 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 518... 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 31030. ...Hart Read more

MD 1760 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR SOUTHEAST WI...NORTHEAST IL...SOUTHWEST LOWER MI...NORTHEAST IN
Mesoscale Discussion 1760 NWS Storm Prediction Center Norman OK 0940 AM CDT Mon Jul 27 2026 Areas affected...southeast WI...northeast IL...southwest Lower MI...northeast IN Concerning...Severe potential...Watch possible Valid 271440Z - 271715Z Probability of Watch Issuance...60 percent SUMMARY...Severe potential will increase into early afternoon across the Lake Michigan vicinity. Timing and storm evolution is a bit uncertain, but a severe thunderstorm probably will be needed in the next few hours. DISCUSSION...A developing bow is currently moving across northeast WI. Additional convection is developing ahead of this feature to the southeast from Green Bay into central Lake Michigan along a moisture and differential heating band within stronger northwesterly flow aloft. Further south across parts of southern WI into northern IL, elevated convection and developing TCU are noted in latest radar and visible satellite imagery within a corridor of extreme instability. It is possible that multiple clusters of strong to severe storms could develop within these two corridors as the furthest north cluster also continues to intensify and develop southeast. While its remains unclear exactly how the risk will evolve over the next few hours, it seems likely that storms will develop within a very unstable airmass characterized by 2000-4000 J/kg MLCAPE, very steep midlevel lapse rates, and 50+ kt deep-layer shear. The most favorable corridor through early afternoon for severe storms producing swaths of damaging winds and isolated hail will be from eastern parts of WI into northeast IL, southern/central Lake Michigan, and southwest Lower MI/northwest IN. Timing of watch issuance is uncertain, but a severe thunderstorm watch will likely be needed at some point by midday/early afternoon. ..Leitman/Hart.. 07/27/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...IWX...GRR...GRB...LOT...MKX... LAT...LON 44948764 43908676 42968600 42508573 41988565 41148650 41138732 41478805 42108900 42788924 43668913 44568838 44948764 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

WW 0519 Status Updates
STATUS REPORT ON WW 519 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 WNW RHI TO 20 SE RHI TO 15 E ESC. ..LEITMAN..07/27/26 ATTN...WFO...MQT...GRB... STATUS REPORT FOR WS 519 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MIC109-271640- MI . MICHIGAN COUNTIES INCLUDED ARE MENOMINEE WIC009-015-029-061-067-069-071-075-078-083-087-115-271640- WI . WISCONSIN COUNTIES INCLUDED ARE BROWN CALUMET DOOR KEWAUNEE LANGLADE LINCOLN MANITOWOC MARINETTE MENOMINEE OCONTO OUTAGAMIE SHAWANO LMZ521-522-541-542-543-563-565-567-271640- CW . ADJACENT COASTAL WATERS INCLUDED ARE Read more

WW 0519 Status Updates
STATUS REPORT ON WW 519 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 S IWD TO 5 NNW IMT TO 10 SSE ESC. ..LEITMAN..07/27/26 ATTN...WFO...MQT...GRB... STATUS REPORT FOR WS 519 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MIC109-271540- MI . MICHIGAN COUNTIES INCLUDED ARE MENOMINEE WIC009-015-029-037-041-061-067-069-071-075-078-083-085-087-115- 271540- WI . WISCONSIN COUNTIES INCLUDED ARE BROWN CALUMET DOOR FLORENCE FOREST KEWAUNEE LANGLADE LINCOLN MANITOWOC MARINETTE MENOMINEE OCONTO ONEIDA OUTAGAMIE SHAWANO LMZ521-522-541-542-543-563-565-567-271540- CW Read more

MD 1758 CONCERNING SEVERE THUNDERSTORM WATCH 518... FOR WESTERN UPPER PENINSULA OF MICHIGAN...NORTHERN WISCONSIN
Mesoscale Discussion 1758 NWS Storm Prediction Center Norman OK 0730 AM CDT Mon Jul 27 2026 Areas affected...Western Upper Peninsula of Michigan...Northern Wisconsin Concerning...Severe Thunderstorm Watch 518... Valid 271230Z - 271430Z The severe weather threat for Severe Thunderstorm Watch 518 continues. SUMMARY...Some intensification of activity over Lake Superior/western Upper Peninsula of Michigan is possible as it moves southeast. Large hail and damaging winds remain possible into mid/late morning. DISCUSSION...Activity over Lake Superior has tended to take a more southward motion over the last hour. A very unstable, but currently capped, airmass is situated in northwest Wisconsin. Continued surface heating may allow low-level cloud cover to abate by late morning/early afternoon. Some intensification of ongoing storms is possible as this process occurs. Large hail and damaging winds would be the main hazards. Depending on the timing/track of these storms, some extension in time/area of WW 518 may be needed later this morning. ..Wendt.. 07/27/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MQT...GRB...DLH... LAT...LON 47009109 47419087 47508983 46518820 45828766 45468793 45408918 47009109 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

MD 1759 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR NORTHEAST ILLINOIS INTO NORTHERN INDIANA AND SOUTHWEST LOWER MICHIGAN
Mesoscale Discussion 1759 NWS Storm Prediction Center Norman OK 0752 AM CDT Mon Jul 27 2026 Areas affected...Northeast Illinois into Northern Indiana and southwest lower Michigan Concerning...Severe potential...Watch possible Valid 271252Z - 271445Z Probability of Watch Issuance...40 percent SUMMARY...A watch is possible this morning for the lower Lake Michigan vicinity, though uncertainty remains high. Convective trends will need to be monitored this morning. DISCUSSION...Current radar CAPPI trends suggest that the storm ongoing in southwest lower Michigan has trended down in intensity over the past 30 minutes. That said, model guidance such as the RRFS and HRRR continue to highlight the southern Lake Michigan vicinity as an area for possible development/intensification later this morning. Objective mesoanalysis shows strong to extreme buoyancy across northern Illinois into parts of northern Indiana. Morning observed soundings from the region show similar MLCAPE values as well as steep mid-level lapse rates and strong shear. Forcing for ascent will be nebulous and cloud cover/capping also limits confidence on where, or if, additional severe storms will develop later this morning. However, visible satellite trends show areas of convective turrets from northeast Illinois into southern Lake Michigan. This area will need to be monitored for a possible watch though uncertainty in this scenario is admittedly high. ..Wendt/Guyer.. 07/27/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...IWX...GRR...IND...LOT... LAT...LON 40448579 40598638 40978710 41438793 41948832 42408822 42448756 41988510 40928484 40318528 40448579 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

WW 0519 Status Updates
STATUS FOR WATCH 0519 HAS NOT BEEN ISSUED YET Read more

WW 0518 Status Updates
STATUS REPORT ON WW 518 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 NNW EAU TO 40 SW ASX TO 45 WNW CMX. ..WENDT..07/27/26 ATTN...WFO...MQT...DLH...FGF...GRB... STATUS REPORT FOR WS 518 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MIC053-131-271440- MI . MICHIGAN COUNTIES INCLUDED ARE GOGEBIC ONTONAGON WIC003-037-041-051-067-069-075-078-083-085-099-113-115-125- 271440- WI . WISCONSIN COUNTIES INCLUDED ARE ASHLAND FLORENCE FOREST IRON LANGLADE LINCOLN MARINETTE MENOMINEE OCONTO ONEIDA PRICE SAWYER SHAWANO VILAS LSZ240-241-242-271440- CW Read more

WW 0518 Status Updates
STATUS REPORT ON WW 518 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 NNW EAU TO 40 SW ASX TO 45 WNW CMX. ..WENDT..07/27/26 ATTN...WFO...MQT...DLH...FGF...GRB... STATUS REPORT FOR WS 518 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MIC053-131-271440- MI . MICHIGAN COUNTIES INCLUDED ARE GOGEBIC ONTONAGON WIC003-037-041-051-067-069-075-078-083-085-099-113-115-125- 271440- WI . WISCONSIN COUNTIES INCLUDED ARE ASHLAND FLORENCE FOREST IRON LANGLADE LINCOLN MARINETTE MENOMINEE OCONTO ONEIDA PRICE SAWYER SHAWANO VILAS LSZ240-241-242-271440- CW Read more

WW 0518 Status Updates
STATUS REPORT ON WW 518 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 NNW EAU TO 40 SW ASX TO 45 WNW CMX. ..WENDT..07/27/26 ATTN...WFO...MQT...DLH...FGF...GRB... STATUS REPORT FOR WS 518 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MIC053-131-271440- MI . MICHIGAN COUNTIES INCLUDED ARE GOGEBIC ONTONAGON WIC003-037-041-051-067-069-075-078-083-085-099-113-115-125- 271440- WI . WISCONSIN COUNTIES INCLUDED ARE ASHLAND FLORENCE FOREST IRON LANGLADE LINCOLN MARINETTE MENOMINEE OCONTO ONEIDA PRICE SAWYER SHAWANO VILAS LSZ240-241-242-271440- CW Read more

WW 518 SEVERE TSTM MI MN WI LS 270630Z - 271400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 518 NWS Storm Prediction Center Norman OK 130 AM CDT Mon Jul 27 2026 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Upper Michigan Northern Minnesota Northern Wisconsin Lake Superior * Effective this Monday morning from 130 AM until 900 AM CDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2 inches in diameter possible Scattered damaging wind gusts to 70 mph possible A tornado or two possible SUMMARY...Scattered thunderstorms will continue to increase in coverage and intensity overnight as they moved southeastward regionally. Large hail will the most common concern overnight, although damaging wind potential could increase toward dawn and beyond if storms begin to cluster and organize. The severe thunderstorm watch area is approximately along and 80 statute miles north and south of a line from 80 miles west of International Falls MN to 15 miles south southeast of Iron Mountain MI. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU8). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 600. Mean storm motion vector 30025. ...Guyer Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0800 AM CDT Mon Jul 27 2026 Valid 271300Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDWEST/LAKE MICHIGAN VICINITY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS... ...SUMMARY... Severe storms capable of strong to severe wind gusts and large hail are expected across the Great Lakes and Midwest through tonight. More sporadic occurrences of damaging wind are possible in the Mid-Atlantic, Tennessee Valley, central High Plains, and southeast Arizona. ...Midwest/Great Lakes to the Ohio/Tennessee Valleys... A complex forecast scenario again exists today complicated by numerous mesoscale factors and well-above-normal short-term guidance variability. There nonetheless is an appreciable broad regional severe potential, at least conditionally, attributable to robust or even extreme source-region buoyancy and an appreciable belt of northwesterly flow aloft (50+ kt at 500 mb), which could easily support well-organized wind-producing swaths regionally into the afternoon and tonight. A high-moisture-content airmass is prevalent regionally to the south of a cold front that extends across South Dakota/Minnesota toward Lake Superior. Several corridors of storms are ongoing early this morning, including across the western Upper Peninsula of Michigan/far northern Wisconsin, as well as southwest lower Michigan, with some uptick in ACCAS/mid-level convection in the predawn hours across eastern Iowa/far southwest Wisconsin. Increasing daytime storms, in terms of coverage/intensity/ organization, may stem from, but are not limited to, these early day corridors. Bouts of large hail will be possible given the degree of vertical shear/buoyancy, and some tornado risk could exist, but the most prominent concern would be for damaging wind potential, particularly if one or more south/southeast-moving forward-propagating clusters emerge, which currently appear most probable this afternoon and tonight across eastern Wisconsin/western Michigan and Lake Michigan vicinity southeastward into Indiana, western Ohio, and Illinois. ...Central High Plains... Moist, post-frontal surface flow is expected across much of Nebraska/South Dakota, shifting from northerly early in the day to more easterly by the afternoon. Dewpoints will initially be in the mid to upper 70s F, although strong boundary-layer mixing will likely result in dewpoints ranging from the upper 50s/low 60s across the Nebraska Panhandle to the low 70s across eastern Nebraska. This reservoir of low-level moisture coupled with strong heating and steep mid-level lapse rates will result in a corridor of moderate to extreme buoyancy from eastern Wyoming/northeast Colorado/southwest South Dakota eastward across south-central South Dakota and much of Nebraska. Most of the guidance indicates a subtle, convectively augmented vorticity maximum will progress eastward through the northern periphery of the Four Corner upper ridge. This should contribute to thunderstorm development across the high terrain, which would then progress downstream into a more moist and unstable airmass. One or more clusters could evolve, but the overall predictability of the convective evolution is low. That said, environmental conditions support the potential for strong to severe gusts, including the potential for some over 75 mph. ...Mid-Atlantic States/Delmarva... Isolated damaging wind potential will exist during the afternoon/evening, especially near/east of I-95 in vicinity of a surface trough, where marginal buoyancy and deep-layer shear could support a few stronger updrafts/downdrafts. ...Southeast Arizona... Isolated severe-caliber wind gusts are possible over southeast Arizona as mid-level moisture and diurnal heating leads to scattered storms over the higher terrain. Cells are expected to move westward into warmer temperatures and deeper boundary-layer mixing, with PWAT over 1.25" and steep low-level lapse rates supporting strong convective outflows. ..Guyer/Wendt.. 07/27/2026 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0800 AM CDT Mon Jul 27 2026 Valid 271300Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDWEST/LAKE MICHIGAN VICINITY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS... ...SUMMARY... Severe storms capable of strong to severe wind gusts and large hail are expected across the Great Lakes and Midwest through tonight. More sporadic occurrences of damaging wind are possible in the Mid-Atlantic, Tennessee Valley, central High Plains, and southeast Arizona. ...Midwest/Great Lakes to the Ohio/Tennessee Valleys... A complex forecast scenario again exists today complicated by numerous mesoscale factors and well-above-normal short-term guidance variability. There nonetheless is an appreciable broad regional severe potential, at least conditionally, attributable to robust or even extreme source-region buoyancy and an appreciable belt of northwesterly flow aloft (50+ kt at 500 mb), which could easily support well-organized wind-producing swaths regionally into the afternoon and tonight. A high-moisture-content airmass is prevalent regionally to the south of a cold front that extends across South Dakota/Minnesota toward Lake Superior. Several corridors of storms are ongoing early this morning, including across the western Upper Peninsula of Michigan/far northern Wisconsin, as well as southwest lower Michigan, with some uptick in ACCAS/mid-level convection in the predawn hours across eastern Iowa/far southwest Wisconsin. Increasing daytime storms, in terms of coverage/intensity/ organization, may stem from, but are not limited to, these early day corridors. Bouts of large hail will be possible given the degree of vertical shear/buoyancy, and some tornado risk could exist, but the most prominent concern would be for damaging wind potential, particularly if one or more south/southeast-moving forward-propagating clusters emerge, which currently appear most probable this afternoon and tonight across eastern Wisconsin/western Michigan and Lake Michigan vicinity southeastward into Indiana, western Ohio, and Illinois. ...Central High Plains... Moist, post-frontal surface flow is expected across much of Nebraska/South Dakota, shifting from northerly early in the day to more easterly by the afternoon. Dewpoints will initially be in the mid to upper 70s F, although strong boundary-layer mixing will likely result in dewpoints ranging from the upper 50s/low 60s across the Nebraska Panhandle to the low 70s across eastern Nebraska. This reservoir of low-level moisture coupled with strong heating and steep mid-level lapse rates will result in a corridor of moderate to extreme buoyancy from eastern Wyoming/northeast Colorado/southwest South Dakota eastward across south-central South Dakota and much of Nebraska. Most of the guidance indicates a subtle, convectively augmented vorticity maximum will progress eastward through the northern periphery of the Four Corner upper ridge. This should contribute to thunderstorm development across the high terrain, which would then progress downstream into a more moist and unstable airmass. One or more clusters could evolve, but the overall predictability of the convective evolution is low. That said, environmental conditions support the potential for strong to severe gusts, including the potential for some over 75 mph. ...Mid-Atlantic States/Delmarva... Isolated damaging wind potential will exist during the afternoon/evening, especially near/east of I-95 in vicinity of a surface trough, where marginal buoyancy and deep-layer shear could support a few stronger updrafts/downdrafts. ...Southeast Arizona... Isolated severe-caliber wind gusts are possible over southeast Arizona as mid-level moisture and diurnal heating leads to scattered storms over the higher terrain. Cells are expected to move westward into warmer temperatures and deeper boundary-layer mixing, with PWAT over 1.25" and steep low-level lapse rates supporting strong convective outflows. ..Guyer/Wendt.. 07/27/2026 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0800 AM CDT Mon Jul 27 2026 Valid 271300Z - 281200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDWEST/LAKE MICHIGAN VICINITY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL HIGH PLAINS... ...SUMMARY... Severe storms capable of strong to severe wind gusts and large hail are expected across the Great Lakes and Midwest through tonight. More sporadic occurrences of damaging wind are possible in the Mid-Atlantic, Tennessee Valley, central High Plains, and southeast Arizona. ...Midwest/Great Lakes to the Ohio/Tennessee Valleys... A complex forecast scenario again exists today complicated by numerous mesoscale factors and well-above-normal short-term guidance variability. There nonetheless is an appreciable broad regional severe potential, at least conditionally, attributable to robust or even extreme source-region buoyancy and an appreciable belt of northwesterly flow aloft (50+ kt at 500 mb), which could easily support well-organized wind-producing swaths regionally into the afternoon and tonight. A high-moisture-content airmass is prevalent regionally to the south of a cold front that extends across South Dakota/Minnesota toward Lake Superior. Several corridors of storms are ongoing early this morning, including across the western Upper Peninsula of Michigan/far northern Wisconsin, as well as southwest lower Michigan, with some uptick in ACCAS/mid-level convection in the predawn hours across eastern Iowa/far southwest Wisconsin. Increasing daytime storms, in terms of coverage/intensity/ organization, may stem from, but are not limited to, these early day corridors. Bouts of large hail will be possible given the degree of vertical shear/buoyancy, and some tornado risk could exist, but the most prominent concern would be for damaging wind potential, particularly if one or more south/southeast-moving forward-propagating clusters emerge, which currently appear most probable this afternoon and tonight across eastern Wisconsin/western Michigan and Lake Michigan vicinity southeastward into Indiana, western Ohio, and Illinois. ...Central High Plains... Moist, post-frontal surface flow is expected across much of Nebraska/South Dakota, shifting from northerly early in the day to more easterly by the afternoon. Dewpoints will initially be in the mid to upper 70s F, although strong boundary-layer mixing will likely result in dewpoints ranging from the upper 50s/low 60s across the Nebraska Panhandle to the low 70s across eastern Nebraska. This reservoir of low-level moisture coupled with strong heating and steep mid-level lapse rates will result in a corridor of moderate to extreme buoyancy from eastern Wyoming/northeast Colorado/southwest South Dakota eastward across south-central South Dakota and much of Nebraska. Most of the guidance indicates a subtle, convectively augmented vorticity maximum will progress eastward through the northern periphery of the Four Corner upper ridge. This should contribute to thunderstorm development across the high terrain, which would then progress downstream into a more moist and unstable airmass. One or more clusters could evolve, but the overall predictability of the convective evolution is low. That said, environmental conditions support the potential for strong to severe gusts, including the potential for some over 75 mph. ...Mid-Atlantic States/Delmarva... Isolated damaging wind potential will exist during the afternoon/evening, especially near/east of I-95 in vicinity of a surface trough, where marginal buoyancy and deep-layer shear could support a few stronger updrafts/downdrafts. ...Southeast Arizona... Isolated severe-caliber wind gusts are possible over southeast Arizona as mid-level moisture and diurnal heating leads to scattered storms over the higher terrain. Cells are expected to move westward into warmer temperatures and deeper boundary-layer mixing, with PWAT over 1.25" and steep low-level lapse rates supporting strong convective outflows. ..Guyer/Wendt.. 07/27/2026 Read more

MD 1757 CONCERNING SEVERE THUNDERSTORM WATCH 518... FOR MINNESOTA ARROWHEAD...FAR NORTHERN WISCONSIN...WESTERN UPPER PENINSULA OF MICHIGAN
Mesoscale Discussion 1757 NWS Storm Prediction Center Norman OK 0526 AM CDT Mon Jul 27 2026 Areas affected...Minnesota Arrowhead...far northern Wisconsin...western Upper Peninsula of Michigan Concerning...Severe Thunderstorm Watch 518... Valid 271026Z - 271230Z The severe weather threat for Severe Thunderstorm Watch 518 continues. SUMMARY...Large hail will be the primary risk with elevated storms moving southeastward through the Minnesota Arrowhead early this morning. Isolated wind damage is also possible with the strongest storms. DISCUSSION...Low-level warm advection and lift from a shortwave trough have reinvigorated convection across the Minnesota Arrowhead early this morning. Steep mid-level lapse rates and effective shear of 40-50 kts will help to organize storms promote a risk of large hail. Though this activity is elevated, stronger downdrafts could reach the surface and produce isolated damage. These risk will eventually extend into far northern Wisconsin and the western Upper Peninsula of Michigan. ..Wendt.. 07/27/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MQT...GRB...DLH... LAT...LON 47879221 48129228 48419047 47438817 47208800 46628842 46118942 46329032 47879221 MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more