The combination of very warm temperatures and high dew points led to extreme apparent temperature values across southwest Wisconsin on the 11th and 12th. The apparent temperature at Prairie Du Chien (Crawford County) was at or above 105 degrees on the afternoon of the 11th, as well as in the late morning and afternoon on the 12th.
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The episode as NWS ARX wrote it up.
The combination of very warm temperatures and high dew points led to extreme apparent temperature values across southwest Wisconsin on the 11th and 12th. The apparent temperature at Prairie Du Chien (Crawford County) was at or above 105 degrees on the afternoon of the 11th, as well as in the late morning and afternoon on the 12th. The maximum apparent temperature was 112 degrees, which occurred on the morning of August 12th.
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 La Crosse, WI wrote its last area forecast discussion before the first event at Aug 11, 2:38 AM CST, 11 hours 7 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 338 AM CDT WED AUG 11 2010 .SHORT TERM...TODAY THROUGH FRIDAY HEAVY RAIN THREAT AGAIN THURSDAY NIGHT THROUGH FRIDAY ALONG WITH HEAT/HUMIDITY CONTINUE TO BE FOCUS OF CONCERN THROUGH THE PERIOD. CURRENTLY WATCHING A BAND OF SHRA/TS TRAVERSING EASTWARD ACROSS THE AREA. HISTORY OF VERY INTENSE DOWNPOURS WITH THIS CONVECTION. HOURLY RAINFALL RATES OF 2-3 INCHES ALSO INDICATED PER ARX RADAR. WATER VAPOR INDICATING THE MAIN MID-LEVEL SHORTWAVE TROUGH THAT WAS PRODUCING LIFT FOR THE CONVECTION EXTENDED FROM NORTHWESTERN MN INTO WESTERN IA. 11.00Z GFS/NAM AND THE 10.21Z IN VERY GOOD AGREEMENT WITH OVER ALL SYNOPTIC EVOLUTION...BUT VARY WITH INDIVIDUAL QPF OUTPUT SOLUTIONS PER GIVEN FORCING MECHANISMS. MAY BE A TRICKY FORECAST TODAY. THIS MAIN BAND OF CONVECTION LOOKS LIKE IT WILL CLEAR THE AREA LATER THIS MORNING...BUT WITH THE MAIN TROUGH AXIS LINGERING BEHIND...COULD SEE SOME INSTABILITY SHRA/TS ACTIVITY BUBBLING UP IN HEATING OF THE DAY. WILL KEEP CHANCY POPS EAST OF THE MISSISSIPPI RIVER TODAY BASED ON THIS. OTHERWISE...WILL HAVE TO PUT UP WITH ANOTHER STEAMY DAY WITH HIGHS IN THE MID-UPPER 80S AND DEW POINTS LINGERING IN THE LOW-MID 70S. THIS WILL PRODUCE HEAT INDICES ONCE AGAIN IN THE 95-100 DEGREE RANGE MAINLY SOUTHWEST OF I-94. RIDGE OF HIGH PRESSURE BUILDS INTO THE AREA TONIGHT FOR CLEARING SKIES AND LIGHT WINDS. THIS WILL SET UP A GOOD RADIATIONAL COOLING CONDITIONS AND GIVEN RECENT HEAVY RAINFALL...WILL LIKELY SEE AREAS-WIDESPREAD FOG AFTER MIDNIGHT. ATTENTION THEN TURNS TO A MID-LEVEL TROUGH MOVING TOWARD THE AREA FROM THE PLAINS THURSDAY NIGHT/FRIDAY MORNING. BOTH THE GFS/NAM SHOWING AN MCS POTENTIAL AS 850MB MOISTURE TRANSPORT INCREASES AHEAD OF THE WAVE. THE NAM IS A BIT FURTHER NORTH WITH THE MCS...TAKING IT ACROSS AREAS ALONG AND SOUTH OF I-90. HEFTY LOOKING QPF AMOUNTS DEPICTED BY THE NAM IN THE 4-4.5 INCH RANGE. THE GFS ON THE OTHERHAND WANTS TO DROP THE MCS SOUTHEAST...JUST WEST OF OUR AREA. NONETHELESS...SIGNAL IS THERE FOR HEAVY RAIN POTENTIAL. THEN LATER FRIDAY AFTERNOON INTO FRIDAY NIGHT...MODELS ARE SHOWING VIGOROUS/DEEP/PATTERN SHIFTING TROUGH AND ASSOCIATED SURFACE COLD FRONT PUSHING INTO THE AREA. SEVERE THREAT MAY BE TRICKY BY FRIDAY AFTERNOON GIVEN THERE IS THE POTENTIAL FOR LEFT OVER CONVECTIVE DEBRIS FROM MORNING COMPLEX. HOWEVER...NAM IS INDICATING AMPLE 0-3KM SHEAR IN THE 30-35KT RANGE WITH MUCAPE IN THE 2500-4500J/KG RANGE BY LATE IN THE AFTERNOON. WILL HAVE TO WATCH THIS CLOSELY FOR SEVERE THREAT. IT APPEARS THE MAIN THREAT WOULD BE DAMAGING WINDS/LARGE HAIL (WITH COOLING ALOFT)...AND YET AGAIN...HEAVY RAINFALL AS THE MUGGY AIRMASS GETS SQUEEZED OUT. WILL KEEP ESF PRODUCT GOING TO HIGHLIGHT THE CONTINUED HEAVY RAIN THREAT FROM THURSDAY NIGHT THROUGH FRIDAY NIGHT. .LONG TERM...FRIDAY NIGHT THROUGH TUESDAY LATEST 11.00Z GFS/ECMWF IN GOOD AGREEMENT THAT THE COLD FRONT/ASSOCIATED SHRA AND TS THREAT WILL CONTINUE TO PUSH THROUGH THE AREA FRIDAY NIGHT AND EVENTUALLY OUT OF THE AREA BY SATURDAY AFTERNOON. THE REST OF THE PERIOD WILL BE MARKED WITH MUCH LOWER DEW POINTS AND COOLER AIRMASS AS MID-LEVEL TROUGH AND CYCLONIC FLOW ESTABLISHES ITSELF OVER THE UPPER MISSISSIPPI RIVER VALLEY/GREAT LAKES REGION. AN EMBEDDED SHORTWAVE TROUGH WITHIN THIS CYCLONIC FLOW IS EXPECTED ROTATE INTO THE AREA ON MONDAY FOR ANOTHER CHANCE OF SHRA/TS. THE MODELS SHOW A MORE VIGOROUS SHORTWAVE TROUGH/REINFORCING SHOT OF COOLER AIR ROTATING INTO THE AREA ON TUESDAY. APPEARS NORTHERN SECTION OF THE FORECAST MAY SEE SOME THUNDERSTORM ACTIVITY FROM THIS SYSTEM. && .AVIATION... TODAY AND TONIGHT EXPECT SHOWERS AND THUNDERSTORMS TO EXIT THE AREA THIS MORNING WITH SKIES GRADUALLY CLEARING ACROSS SOUTHEAST MINNESOTA...INTO SOUTHWEST WISCONSIN. WITH A VERY HUMID AIRMASS IN PLACE...EXPECT BR AND FG TO DEVELOP AT THE TAF SITES THIS MORNING. EXPECT CLEARING TO OCCUR EARLIER AT KRST WITH VSBY BEING REDUCED TO IFR CONDITIONS FROM 11Z TO 13Z. EXPECT CLEARING TO OCCUR LATER AT KLSE WHICH MAY INHIBIT FOG DEVELOPMENT...SO HAVE INCLUDED MVFR VSBY WITH BR FROM 10Z TO 13Z. IF CLEARING OCCURS EARLIER VSBY COULD DROP TO IFR CONDITIONS. THERE IS UNCERTAINTY IN HOW QUICKLY THE HIGH CLOUDS WILL SHIFT EAST OF THE AREA SO TRENDS WILL BE MONITORED CLOSELY THIS MORNING. EXPECT FG AND STRATUS TO DISSIPATE BY THE MID MORNING HOURS WITH CU DEVELOPING IN THE LATE MORNING INTO THE AFTERNOON WITH BASES AROUND 5KFT. WINDS WILL BECOME LIGHT AND VARIABLE THIS EVENING INTO THE OVERNIGHT HOURS UNDER MOSTLY CLEAR SKIES. THIS WILL SET THE STAGE FOR FG DEVELOPMENT ACROSS MUCH OF THE AREA AFTER MIDNIGHT. && .HYDROLOGY... NOT OUT OF THE WOODS YET CONCERNING HEAVY RAINFALL POTENTIAL. WILL BE WATCHING THURSDAY NIGHT THROUGH SATURDAY MORNING FOR SEVERAL BOUTS OF SHRA/TS ACTIVITY TIED WITH VARIOUS UPPER LEVEL DISTURBANCES AND SURFACE BOUNDARIES. THE POTENTIAL IS THERE FOR A LARGE SHRA/TS COMPLEX ACROSS THE AREA THURSDAY NIGHT AS LOW LEVEL JET INCREASES AHEAD OF A MID-LEVEL TROUGH MOVING TOWARD THE AREA FROM TH PLAINS. THEN FOR FRIDAY THROUGH SATURDAY MORNING...EXPECTING A COLD FRONT TO SHOVE THROUGH THE AREA FOR PERHAPS SOME SEVERE STORMS WITH HEAVY RAINFALL. WITH ALREADY SATURATED GROUND...SIGNIFICANT RUNOFF COULD OCCUR...PRODUCING RAPID RIVER RISES. FLOODING RAIN THREAT APPEARS OVER BY SATURDAY AFTERNOON WITH COOLER/DRIER AIRMASS MOVING IN THROUGH THE REMAINDER OF THE WEEKEND/EARLY NEXT WEEK. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && SHORT/LONG TERM... DAS AVIATION.......... JRW
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE LA CROSSE WI 1138 AM CDT WED AUG 11 2010 IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-032>034- 041>044-053>055-061-121100- ADAMS-ALLAMAKEE-BUFFALO-CHICKASAW-CLARK-CLAYTON-CRAWFORD-DODGE- FAYETTE-FILLMORE-FLOYD-GRANT-HOUSTON-HOWARD-JACKSON-JUNEAU-LA CROSSE- MITCHELL-MONROE-MOWER-OLMSTED-RICHLAND-TAYLOR-TREMPEALEAU-VERNON- WABASHA-WINNESHIEK-WINONA- 1138 AM CDT WED AUG 11 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PARTS OF NORTHEAST IOWA...SOUTHEAST MINNESOTA...AND SOUTHWEST INTO CENTRAL WISCONSIN. .DAY ONE...THIS AFTERNOON AND TONIGHT AN ISOLATED THUNDERSTORM OR TWO ARE POSSIBLE LATE THIS AFTERNOON INTO THE EVENING HOURS MAINLY OVER SOUTHEAST MINNESOTA AND WISCONSIN BUT OUTSIDE OF SOME HEAVY RAIN AND A LIGHTNING RISK...NO SEVERE WEATHER IS EXPECTED. VERY WARM AND HUMID CONDITIONS WILL PREVAIL AGAIN WITH HEAT INDICIES EXPECTED TO APPROACH 100 OVER PARTS OF NORTHEAST IOWA AND NEIGHBORING COUNTIES IN MINNESOTA AND WISCONSIN. GIVEN THE PROLONGED NATURE OF THIS HOT AND HUMID SPELL...MORE HEAT RELATED ILLNESSES ARE POSSIBLE. AREAS OF FOG MAY ALSO DEVELOP TONIGHT...WHICH COULD BECOME DENSE IN RIVER VALLEYS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY MORE THUNDERSTORMS ARE EXPECTED IN THE REGION THURSDAY NIGHT THROUGH SATURDAY. HEAVY RAIN APPEARS LIKELY WITH THESE THUNDERSTORM COMPLEXES BUT OTHER SEVERE WEATHER IS POSSIBLE INCLUDING GUSTY WINDS AT TIMES. WITH RECENT HEAVY RAINFALL ACROSS THE AREA...ANY ADDITIONAL HEAVY RAIN COULD LEAD TO FLOODING AND RESULT IN RAPID RISES ON AREA CREEKS AND RIVERS. MONITOR RAINFALL AND WATER CONDITIONS CLOSELY INTO THE WEEKEND. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THURSDAY NIGHT AND AGAIN ON FRIDAY. PLEASE MONITOR LATER OUTLOOKS AND FORECASTS FOR UPDATES...ESPECIALLY REGARDING FLOOD CONCERNS. .EMERGENCY MANAGEMENT COORDINATION... NO CALL IS SCHEDULED. SHEA
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE LA CROSSE WI 1216 PM CDT WED AUG 11 2010 IAZ008>011-018-019-029-030-MNZ094-095-WIZ054-061-112000- ALLAMAKEE-CHICKASAW-CLAYTON-CRAWFORD-FAYETTE-FILLMORE-FLOYD-GRANT- HOWARD-MITCHELL-MOWER-WINNESHIEK- 1216 PM CDT WED AUG 11 2010 ...HEAT AND HUMIDITY HIGH AGAIN TODAY... THE COMBINATION OF VERY WARM AFTERNOON AND EARLY EVENING TEMPERATURES WITH HIGH HUMIDITY LEVELS WILL PRODUCE HEAT INDICIES FROM 95 TO 100 AGAIN TODAY. SOME AREAS COULD TOP THAT FOR A FEW HOURS AND WITH THE PROLONGED STRETCH OF HEAT...HEAT RELATED STRESS OR ILLNESS COULD BECOME MORE OF A PROBLEM. THE NATIONAL WEATHER SERVICE URGES PEOPLE TO BE AWARE OF HEAT RELATED DANGERS. IF WORKING OUTDOORS...TAKE FREQUENT BREAKS AND DRINK PLENTY OF WATER. TAKE BREAKS IN AN AIR CONDITIONED LOCATION IF POSSIBLE. CHECK THE ELDERLY AND SMALL CHILDREN AS WELL. NEVER LEAVE A SMALL CHILD OR PET IN A CAR FOR EVEN A BRIEF PERIOD IN THIS HEAT. A HEAT ADVISORY MAY BE NEEDED IN AREAS LATER TODAY. SHEA
The national radar mosaic for the moment the first event began.
2 heat. Local standard time, as filed.
The automated weather observing equipment at Prairie Du Chien recorded a maximum apparent temperature of 106 degrees. This occurred as the temperature was 91 degrees with a dew point of 78 degrees.
The automated weather observing equipment at Prairie Du Chien recorded a maximum apparent temperature of 112 degrees. This occurred as the temperature was 91 degrees with a dew point of 81 degrees.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2010Every state in 2010This day in weather historyWarnings in Wisconsin, August 2010
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: 249599, 249600.