Severe thunderstorms crossed southern Wisconsin during the afternoon hours of July 21st. The storms produced damaging wind gusts as well as hail up to 1 inch.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS MKX wrote it up.
Severe thunderstorms crossed southern Wisconsin during the afternoon hours of July 21st. The storms produced damaging wind gusts as well as hail up to 1 inch. Two people were hurt when their horses were struck by lightning while riding in the Kettle Moraine Forest near Eagle in Waukesha County. The thunderstorms formed in a region of focused warm air advection, with lift aided by vorticity advection from a short wave that tracked across the region.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Milwaukee, WI wrote its last area forecast discussion before the first event at Jul 21, 10:00 AM CST, 4 hours 30 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 1100 AM CDT SUN JUL 21 2013 .AVIATION/18Z TAFS/...VFR THIS PERIOD. WATCHING TWO DISTINCT AREAS OF CONVECTION...ONE ACROSS WC WI MOVG EWD...EXPECTED TO STAY WELL NORTH OF TAF SITES. THE OTHER IS NC IA HAS A NICE CURL IN THE REFLECTIVITY DATA AND ASSOCIATED WITH A NICE UPPER WAVE. AIRMASS MUCH MORE UNSTABLE ACROSS IA INTO NW IL. CONCERNED SOME OF THIS AQTIVITY WILL WORK INTO SC WI LATER THIS AFTERNOON/EVENING...IN VICINITY OF ML CAPE/LI GRADIENT. WAA SIGNATURE PICKS UP A BIT TONIGHT SO CANNOT ELIMINATE THE TSRA CHANCES. COLD FRONT APPROACHES LATER MONDAY SO MORE POTENTIAL FOR TSRA. PC && .PREV DISCUSSION... /ISSUED 351 AM CDT SUN JUL 21 2013/ SHORT TERM... TODAY AND TONIGHT...FORECAST CONFIDENCE LOW TO MEDIUM. ISOLATED ELEVATED THUNDERSTORMS OVER WESTERN AND NORTHERN PORTIONS OF FORECAST AREA ON LEADING EDGE OF 850 MB WARM AIR ADVECTION. SOME MODELS WERE TRYING TO BRING LINEAR MCS...CURRENTLY MOVING INTO WESTERN IOWA...INTO THE AREA LATER THIS MORNING. DOES NOT LOOK LIKE IT WILL HOLD TOGETHER WITH CLOUD TOPS COOLING ON LATEST IR LOOPS BUT CLOUD DEBRIS WILL AFFECT TEMPERATURES AND INSTABILITY. LIFT DIMINISHING WITH ASSOCIATED SHORT WAVE WEAKENING AS IT MOVES INTO REGION THIS AFTERNOON. STILL HAVE AN OVERALL UNSTABLE AIR MASS IN PLACE THOUGH MODELS HAVING TROUBLE WITH AMOUNTS AND PLACEMENT OF QPF MAXIMA WITH OVERALL WEAK FORCING MECHANISMS SO WILL HAVE CHANCE POPS ..HIGHEST IN THE WEST...UNTIL TRENDS FOR TIMING AND COVERAGE ARE REVEALED. WILL TREND POPS OUT FROM WEST TO EAST TONIGHT...THOUGH LATEST 06Z NAM INDICATES ALL PCPN WILL END AROUND 00Z AS FORCING WITH SHORT WAVE PASSES SOUTH OF AREA AND WEAK THERMAL FORCING TOT HE NORTH PER LAYER Q-VECTOR CONVERGENCE FORECASTS. MONDAY AND MONDAY NIGHT...FORECAST CONFIDENCE MEDIUM. ANY SUNDAY NIGHT PRECIP SHOULD BE GONE BY MONDAY MORNING...BUT MODELS INSIST ON HANGING UP A FEW THUNDERSTORMS NEAR THE LAKESHORE IN SOUTHEAST WI...SO KEPT SMALL POPS THERE THROUGH 15Z. THE MAJORITY OF THE DAY SHOULD BE DRY WITH SOME SUNSHINE. 925MB TEMPS EXPECTED TO INCREASE TO 23-24C AHEAD OF AN APPROACHING SHORTWAVE TROUGH. THEREFORE...HIGHS MONDAY SHOULD BE IN THE MID/UPPER 80S WITH A SOUTHWEST WIND. DEWPOINT TEMPS WILL BE IN THE MID 60S...SO IT WILL FEEL A LITTLE STICKY. THE SHORTWAVE TROUGH WILL MOVE ACROSS ONTARIO MONDAY NIGHT AND THE ASSOCIATED SURFACE LOW PRESSURE TROUGH/COLD FRONT WILL MARCH SOUTHEAST ACROSS WISCONSIN AND CLEAR THE STATE BY LATE TUE MORNING. MODEL SOUNDINGS SHOW MODERATE CAPE AND SHEAR IN THE VICINITY OF THE FRONT TO WARRANT THUNDERSTORMS. DEEP FORCING AND DEEP MOISTURE WILL BE THE FACTORS IN QUESTION FOR THUNDERSTORM COVERAGE ALONG THIS FRONT. THE BEST CHANCE FOR STORMS APPEARS TO BE TOWARD EAST CENTRAL WI TUE NIGHT...THUS HAVE LIKELY POPS CONFINED TO THE NORTH HALF OF THE MKX FORECAST AREA MAINLY AFTER MIDNIGHT. EXPECTING THE FRONTAL PRECIP TO GRADUALLY WEAKEN AS IT REACHES SOUTHEAST WI TUE MORNING. TAPERED OFF POPS ACCORDINGLY. IT WILL ULTIMATELY DEPEND ON THE TIMING OF WEAK SHORTWAVES IN THE 500MB FLOW COINCIDING WITH THE SURFACE FRONT TO DETERMINE STORM COVERAGE. TUESDAY...FORECAST CONFIDENCE MEDIUM. THE TIMING OF THE FRONT MOVING THROUGH SOUTHEAST WI HAS BEEN SLOWING DOWN IN THE LATEST MODEL RUNS. THEREFORE...EXPANDED THE CHANCE POPS BACK INTO SOUTH CENTRAL WI TUE MORNING. DRY WEATHER IS EXPECTED BEHIND THE FRONT BY TUE AFTERNOON AND THERE SHOULD BE SOME SUNSHINE AS WELL. LONG TERM... WEDNESDAY AND THURSDAY...FORECAST CONFIDENCE HIGH. SURFACE HIGH PRESSURE WILL SETTLE INTO THE GREAT LAKES REGION WITH WEAK MID AND UPPER LEVEL RIDGING MOVING INTO THE CENTER OF THE COUNTRY. TEMPS WILL BE A LITTLE BELOW NORMAL...WITH HIGHS EXPECTED IN THE UPPER 70S. THUNDERSTORM CHANCES ARE BACK IN THE FORECAST FOR THU AFTERNOON AND NIGHT...BUT THESE SEEM MINIMAL GIVEN THE DRY AIR IN PLACE OVER SOUTHERN WI AT THIS TIME AND THE VERY WEAK FORCING ASSOCIATED WITH THE MODEL QPF. FRIDAY THROUGH SUNDAY...FORECAST CONFIDENCE MEDIUM. IT IS UNCLEAR WHEN EXACTLY THE NEXT CHANCE FOR THUNDERSTORMS WILL ARRIVE IN SOUTHERN WI. A 500MB UPPER LOW WILL BE DROPPING DOWN THROUGH THE GREAT LAKES REGION SOMETIME OVER THE WEEKEND AND WILL PRODUCE A CHANCE FOR THUNDERSTORMS FOR A SHORT PERIOD OF TIME WITH THE VORTICITY ADVECTION AND 850MB BAROCLINIC ZONE AHEAD OF IT. BUT THERE ARE DIFFERENCES IN TIMING...THUS SMALL CHANCE POPS EACH DAY FOR NEXT WEEKEND. IT DOES NOT LOOK LIKE A RAINY WEEKEND AND THE CHANCE WE HAVE FOR ANY SUBSTANTIAL PRECIP IS NOT VERY GOOD. AVIATION/12Z TAFS/...VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. WILL LOOK AT LATEST TRENDS PRIOR TO ISSUANCE BUT WILL LIKELY KEEP THUNDERSTORM CHANCES LIMITED TO KMSN FOR NOW. LIGHT EAST WINDS TO SHIFT SOUTHEAST...AND EVENTUALLY SOUTH BY END OF FORECAST PERIOD. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && TODAY/TONIGHT AND AVIATION/MARINE...REM MONDAY THROUGH SATURDAY...MRC
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 443 AM CDT SUN JUL 21 2013 WIZ046-047-051-052-056>060-062>072-220945- MARQUETTE-GREEN LAKE-FOND DU LAC-SHEBOYGAN-SAUK-COLUMBIA-DODGE- WASHINGTON-OZAUKEE-IOWA-DANE-JEFFERSON-WAUKESHA-MILWAUKEE- LAFAYETTE-GREEN-ROCK-WALWORTH-RACINE-KENOSHA- 443 AM CDT SUN JUL 21 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL WISCONSIN...SOUTH CENTRAL WISCONSIN AND SOUTHEAST WISCONSIN. .DAY ONE...TODAY AND TONIGHT LOOK FOR ISOLATED THUNDERSTORMS...MAINLY NORTH OF I-94 THIS MORNING. THERE IS A CHANCE OF THUNDERSTORMS ACROSS ALL OF SOUTHERN WISCONSIN THIS AFTERNOON AND TONIGHT. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS EARLY MONDAY...AND A BETTER CHANCE MONDAY AFTERNOON THROUGH MONDAY NIGHT AS A WEAK LOW PRESSURE AREA AFFECTS THE REGION EARLY MONDAY...FOLLOWED BY A TRAILING COLD FRONT FOR MONDAY NIGHT. THE CHANCE FOR THUNDERSTORMS RETURNS THURSDAY NIGHT INTO THE WEEKEND AS A WEAK COLD FRONT MAY STALL IN THE VICINITY OF SOUTHERN WISCONSIN. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL LIKELY NOT BE NEEDED BUT WILL CLOSELY MONITOR FOR MONDAY NIGHT. LMZ643>646-220945- SHEBOYGAN TO PORT WASHINGTON WI- PORT WASHINGTON TO NORTH POINT LIGHT WI- NORTH POINT LIGHT TO WIND POINT WI- WIND POINT WI TO WINTHROP HARBOR IL- 443 AM CDT SUN JUL 21 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF LAKE MICHIGAN. .DAY ONE...TODAY AND TONIGHT THERE IS A CHANCE FOR THUNDERSTORMS THIS AFTERNOON AND TONIGHT. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS EARLY MONDAY...AND A BETTER CHANCE MONDAY AFTERNOON THROUGH MONDAY NIGHT AS A WEAK LOW PRESSURE AREA AFFECTS THE REGION EARLY MONDAY...FOLLOWED BY A TRAILING COLD FRONT FOR MONDAY NIGHT. THE CHANCE FOR THUNDERSTORMS RETURNS THURSDAY NIGHT INTO THE WEEKEND AS A WEAK COLD FRONT MAY STALL IN THE VICINITY OF SOUTHERN WISCONSIN. REM WWW.WEATHER.GOV/MKX
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 234 PM CDT SUN JUL 21 2013 WIZ063-212030- DANE- 234 PM CDT SUN JUL 21 2013 ...STRONG THUNDERSTORMS MOVING INTO SOUTH CENTRAL DANE COUNTY... AT 230 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 10 MILES WEST OF FITCHBURG TO 9 MILES SOUTH OF OREGON...MOVING NORTHEAST AT 15 MPH. PENNY SIZE HAIL...WINDS GREATER THAN 30 MPH...FREQUENT CLOUD TO GROUND LIGHTNING...BRIEF HEAVY DOWNPOURS...ARE POSSIBLE WITH THESE STORMS. * THUNDERSTORMS WILL BE NEAR... OREGON BY 255 PM CDT... FITCHBURG BY 305 PM CDT... STOUGHTON BY 315 PM CDT... GUSTY WINDS MAY CAUSE SMALL OBJECTS SUCH AS TRASH BINS TO BLOW AROUND. STAY AWAY FROM HIGH OBJECTS OUTDOORS SUCH AS TREES. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THESE STORMS HAVE PASSED. MGG
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 302 PM CDT SUN JUL 21 2013 WIZ056-212100- SAUK- 302 PM CDT SUN JUL 21 2013 ...STRONG THUNDERSTORMS OVER SAUK COUNTY... AT 300 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED SEVERAL STRONG THUNDERSTORMS OVER SAUK COUNTY. PENNY SIZE HAIL...WINDS GREATER THAN 30 MPH...FREQUENT CLOUD TO GROUND LIGHTNING...BRIEF HEAVY DOWNPOURS...ARE POSSIBLE WITH THESE STORMS OVER THE NEXT HOUR. THUNDERSTORMS WILL CONTINUE THROUGH THE AFTERNOON. * THE THUNDERSTORM WILL BE NEAR... LONE ROCK AIRPORT BY 310 PM CDT... SPRING GREEN BY 330 PM CDT... GUSTY WINDS MAY CAUSE SMALL OBJECTS SUCH AS TRASH BINS TO BLOW AROUND. STAY AWAY FROM HIGH OBJECTS OUTDOORS SUCH AS TREES. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THIS STORM HAS PASSED. MGG
The Milwaukee radar (KMKX), 71 km away, was scanning. The volume nearest the first event began at 20:31 UTC.
5 thunderstorm wind, 2 hail, 1 lightning. Local standard time, as filed.
The Dane County 911 call Center reported a roof was blown off a home 1 mile south of De Forest with debris from the roof damaging other homes by a possible gustnado as two outflow boundaries collided over the area. Wind gusts were estimated at 60 mph (52 knots).
Lightning struck the ground near a group of horse riders in the Kettle Moraine Forest near Eagle. The lightning traveled through the wet ground and passed through two of the horses and one of the riders. The second rider was injured when thrown from her horse after it was struck.
A trained spotter reported hail up to 3/4 of an inch in diameter in the Village of Eagle.
The Walworth County 911 Call Center received reports of trees and power lines downed by thunderstorm wind gusts estimated at 60 mph (52 knots) in East Troy.
A trained spotter reported trees downed and roof damage caused by thunderstorm wind gusts estimated at 60 mph (52 knots) along a path from Whitewater to 1 mile east of Whitewater.
Law enforcement officials reported hail up to 1 inch in diameter in Whitewater.
Law enforcement officials reported trees and power lines downed by thunderstorm wind gusts estimated at 60 mph (52 knots) in in the town of La Grange.
An NWS employee reported corn flattened in several fields along a path from 1 mile west-northwest of Waterford to 1 mile west-northwest of Union Grove by thunderstorm wind gusts estimated at 58 mph (50 knots).
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2013Every state in 2013This day in weather historyWarnings in Wisconsin, July 2013
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 470936, 470939, 470937, 470932, 470933, 470938, 470934, 470935.