Severe thunderstorms developed during the early afternoon of August 20th and produced some isolated wind damage in Houston County.
Every event with a place to put it. Tap one for its entry below.
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 ARX wrote it up.
Severe thunderstorms developed during the early afternoon of August 20th and produced some isolated wind damage in Houston County.
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 20, 12:28 PM CST, 1 hour 13 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 128 PM CDT FRI AUG 20 2010 .UPDATE... MONITORING CONVECTIVE TRENDS ACROSS THE REGION FOR THIS AFTERNOON AND SOME POSSIBLE SEVERE WEATHER. A WARM FRONT HAS TRACKED NORTHWARD INTO NORTHERN WISCONSIN THIS MORNING AND APPEARS TO STRETCH FROM THE TWIN CITIES EAST TO NORTH OF MEDFORD. SURFACE BASED INSTABILITY HAS INCREASED ACROSS MUCH OF WISCONSIN BASED ON THE 20.17Z WHICH SHOWS ABOUT 3000 TO 4000 J/KG OF CAPE ACROSS THE SOUTHERN HALF OF WISCONSIN. 0-6KM SHEAR REMAINS THE BEST ACROSS NORTHEAST WISCONSIN WITH 0-3KM SHEAR OF ABOUT 30KTS ACROSS SOUTHERN WISCONSIN. THE THREAT FOR ANY TORNADOES APPEARS MINIMAL GIVEN THAT THE WARM FRONT IS NORTH OF TAYLOR COUNTY NOW. THE MAIN THREATS WILL BE WITH LARGE HAIL GIVEN THE HIGH INSTABILITY...BUT STRONG STRAIGHT LINE WINDS CAN NOT BE RULED OUT GIVEN THE DECENT 0-3KM SHEAR. THE BEST CHANCES FOR THESE STORMS APPEARS TO BE THIS AFTERNOON BEFORE SUNSET. && .PREV DISCUSSION... /ISSUED 327 AM CDT FRI AUG 20 2010/ SHORT TERM...THROUGH SUNDAY MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES TODAY INTO TONIGHT. SURFACE ANALYSIS EARLY THIS MORNING SHOWS AN AREA OF LOW PRESSURE OVER CENTRAL SOUTH DAKOTA. A WARM FRONT EXTENDED EAST OF THE LOW ACROSS MINNESOTA INTO NORTHERN WISCONSIN WITH A TROUGH OF LOW PRESSURE SOUTH ACROSS NEBRASKA INTO KANSAS. LOCAL AND REGIONAL RADARS SHOW A COMPLEX OF SHOWERS AND THUNDERSTORMS ALONG THE WARM FRONT FROM MINNESOTA INTO WISCONSIN. THE LARGEST CONCENTRATION OF SHOWERS AND STORMS ALONG THE WARM FRONT WAS MOVING INTO NORTHEAST MINNESOTA AND NORTHWEST WISCONSIN AND HAS YET TO TAKE MUCH OF A TURN TO THE EAST. CORFIDI VECTORS OVER EASTERN MINNESOTA ARE STILL SOUTHWEST BUT DO TURN TO THE WEST AHEAD OF THE COMPLEX OF STORMS. THIS IMPLIES THERE STILL MAY BE A TURN TO THE EAST AS INDICATED BY ALMOST ALL OF THE SHORT RANGE MESO SCALE MODELS. THIS WILL HAVE TO HAPPEN SOON FOR THIS TO CLIP THE NORTHERN SECTIONS OF THE FORECAST AREA...OTHERWISE THE RAIN CHANCES ACROSS THIS AREA FOR THE EARLY MORNING HOURS WILL HAVE TO BE ADJUSTED DOWN. ONCE THIS COMPLEX OF STORMS MOVES BY...THERE SHOULD BE A LULL IN THE ACTION THROUGH THE LATE MORNING AND EARLY AFTERNOON BEFORE MORE ACTIVITY FORMS. THE SHORT WAVE TROUGHS CURRENTLY OVER NORTH DAKOTA...WYOMING AND COLORADO ARE ALL EXPECTED TO BE OVER THE UPPER MIDWEST DURING THE AFTERNOON. THE NORTH DAKOTA WAVE IS ANTICIPATED TO WORK ON THE WARM FRONT AND CAUSE ADDITIONAL STORMS TO FIRE ACROSS NORTHERN WISCONSIN INTO THE U.P OF MICHIGAN. MEANWHILE...THE WYOMING AND COLORADO WAVES SHOULD WORK EAST INTO IOWA AND MISSOURI WITH THE 20.00Z NAM SHOWING THE WAVE COMING INTO IOWA PRODUCING AROUND 4 PVU/S OF VORTICITY ADVECTION IN THE 500 TO 300 MB LAYER BETWEEN 20.21Z AND 21.00Z. THIS WAVE SHOULD ALSO HELP PUSH THE SURFACE LOW INTO CENTRAL MINNESOTA WITH THE TROUGH OF LOW PRESSURE SOUTH ACROSS IOWA. THE LOW LEVEL FORCING WITH THIS LOW AND TROUGH DO NOT LOOK OVERLY IMPRESSIVE WITH ONLY SOME WEAK BUT DISORGANIZED FRONTOGENESIS IN THE 1000-850 MB LAYER. THE BEST WARM AIR ADVECTION SHOULD OCCUR NORTH OF THE AREA ALONG AND NORTH OF THE WARM FRONT AND TO THE SOUTH WITH THE SOUTHERN WAVE OVER MISSOURI. THIS LEAVES A WEAK AREA OF WARM AIR ADVECTION OVER THE AREA THIS AFTERNOON PRODUCING UP TO 3 UBAR/S OF UP GLIDE ON THE 310K ISENTROPIC SURFACE. CONFIDENCE ON HOW MUCH DEVELOPMENT WILL OCCUR BETWEEN THE TWO STRONGER SHORT WAVE TROUGHS AND OVER THE AREA IS NOT HIGH GIVEN THE WEAK OVERALL FORCING SIGNALS. NONE THE LESS...THE SHORT RANGE MESO SCALE MODELS INCLUDING THE 20.00Z SPC WRF AND EAST ARW ALONG WITH THE NAM AND 20.00Z ECMWF SHOW SOME DEVELOPMENT OCCURRING ALONG THE TROUGH DURING THE LATE AFTERNOON. PLACEMENT OF THIS DEVELOPMENT IS PRIMARILY ALONG AND EAST OF THE MISSISSIPPI RIVER AND HAVE TRIED TO CAPTURE THIS WITH THE HIGHEST RAIN CHANCES LATE THIS AFTERNOON OVER WISCONSIN. IF THIS ACTIVITY DOES INDEED DEVELOP THERE SHOULD BE SOME SEVERE WEATHER THREAT WITH IT. THE NAM DOES SUGGEST THE POTENTIAL FOR BETWEEN 1500 AND 2000 J/KG OF ML CAPE BUT THE SHEAR MAY NOT BE ALL THE GREAT. AT MOST 25 TO 30 KNOTS OF 0-3 KM SHEAR WILL BE PRESENT IF THE LOW LEVEL CAP BREAKS ALLOWING FOR SURFACE BASED CONVECTION TO FORM ALLOWING FOR AN ISOLATED DAMAGING WIND GUST THREAT. ALL THE MODELS SHOW SOME MID LEVEL COOLING OCCURRING ABOVE THE CAP TO HELP ERODE IT FROM ABOVE BUT WITH THE LOW LEVEL WARM AIR ADVECTION CONTINUING...NOT SURE THIS WILL BE ENOUGH TO TOTALLY BREAK THE CAP. FORECAST SOUNDINGS FROM THE MODELS SHOW THE CAP BREAKING LATE THIS AFTERNOON BUT THAT COULD BE IN RESPONSE TO THE CONVECTIVE SCHEMES KICKING IN AND DEVELOPING THE CONVECTION AS THE CAP BREAKS IN THE BUFKIT SOUNDINGS AT THE SAME TIME IT STARTS RAINING. IF THE CAP DOES NOT BREAK...WOULD EXPECT ANY STORMS THAT DO DEVELOP TO REMAIN ELEVATED WITH A VERY MINIMAL SEVERE THREAT. ANY ACTIVITY THAT DOES DEVELOP THIS AFTERNOON WILL PUSH EAST OF THE AREA DURING THE EVENING. SOME FOG POTENTIAL FOR TONIGHT IF THE SKIES CAN CLEAR SOON ENOUGH WITH THE POSSIBILITY OF PLENTY OF MOISTURE FROM ANY RAIN AVAILABLE TO HELP WITH THE FOG PRODUCTION. A BETTER FOG NIGHT FOR THE RIVER VALLEYS MAY BE SETTING UP FOR SATURDAY NIGHT INTO SUNDAY MORNING. HIGH PRESSURE SHOULD BE OVER THE AREA FOR CLEAR SKIES AND LIGHT WINDS. DEW POINTS ARE NOT EXPECTED TO DECREASE THAT MUCH WHICH MAY END UP KEEPING AIR TEMPERATURES NEAR THE WATER TEMPERATURES OVER THE SMALLER RIVERS WHICH MAY LIMIT THE VALLEY FOG TO THE WISCONSIN AND MISSISSIPPI RIVER VALLEYS. LONG TERM...SUNDAY NIGHT THROUGH THURSDAY BOTH THE 20.00Z GFS AND ECMWF INDICATE A POSITIVELY TILTED UPPER TROUGH AND SURFACE COLD FRONT WILL CROSS THE UPPER MIDWEST MONDAY NIGHT THROUGH TUESDAY. WITH THE POSITIVE TILT TO THE SYSTEM...IT SHOULD BE WEAKENING AS IT COME THROUGH AND THERE MAY NOT BE A LOT OF RAIN LEFT WITH IT BY THE TIME IT GETS TO THE LOCAL AREA. THE CURRENT 20 TO 30 PERCENT RAIN CHANCES SEEM APPROPRIATE ALTHOUGH THERE MAY NEED TO BE A RAIN CHANCE INCLUDED FOR TUESDAY AFTERNOON WITH THE ECMWF SUGGESTING THE SYSTEM MAY NOT HAVE CLEARED THE REGION YET. AVIATION... TWO POTENTIAL ROUNDS OF SHOWERS AND THUNDERSTORMS MAY IMPACT THE TAF SITES AS A LOW PRESSURE SYSTEM MOVES THROUGH...BUT NEITHER ROUND IS CERTAIN. THE FIRST ROUND WOULD OCCUR THIS MORNING...WITH SHOWERS AND STORMS MOVING EAST OUT OF SOUTHWEST MINNESOTA. HOWEVER..THEY MAY END UP TRACKING NORTH OF THE TAF SITES...AND AS SUCH HAVE MAINTAINED VCSH WITH NO CB MENTION FROM 09-15Z. THE TRACK OF THE PRECIPITATION WILL NEED TO BE MONITORED THIS MORNING FOR POSSIBLE TAF AMENDMENTS. LATER THIS AFTERNOON AND INTO THIS EVENING...A WEAK COLD FRONT ASSOCIATED WITH THE SYSTEM IS FORECAST TO CROSS THE TAF SITES. SHOWERS AND THUNDERSTORMS MAY FIRE ALONG THE FRONT...DEPENDING ON HOW HEATING CAN OCCUR THROUGH A CIRROSTRATUS DECK THAT SHOULD BE IN PLACE MUCH OF THE DAY. AT THIS POINT...ONLY HAVE ENOUGH CONFIDENCE TO INCLUDE A CB MENTION FOR 21-03Z...BUT IT IS CONCEIVABLE FOR BOTH SITES TO END UP DRY. ON THE OTHER HAND...SHOULD STORMS FORM...THERE IS THE POTENTIAL FOR THEM TO PRODUCE STRONG WIND GUSTS AND POSSIBLY HAIL AS WELL. THEREFORE...THE AFTERNOON FORECAST ALSO NEEDS TO BE MONITORED. THERE ARE SOME BR/FOG CONCERNS AS WELL. THE FIRST COMES THIS MORNING...WITH MVFR BR EXPECTED UNTIL DAYTIME HEATING CAN MIX IT OUT AROUND 15Z. DEPENDING ON THE AMOUNT OF CLEARING TONIGHT AND IF RAIN OCCURS...COULD SEE IFR OR LOWER VSBY FOG DEVELOP LATE TONIGHT...DUE TO LOW LEVEL MOISTURE NOT BEING SCOURED OUT VERY WELL BY THE COLD FRONT. WILL BE LOOKING AT THIS MORE FOR THE 12Z TAF ISSUANCE. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && UPDATE...HALBACH SHORT/LONG TERM...04 AVIATION...AJ/WETENKAMP
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE LA CROSSE WI 502 AM CDT FRI AUG 20 2010 IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-032>034- 041>044-053>055-061-211000- 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- 502 AM CDT FRI AUG 20 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PARTS OF SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND SOUTHWEST INTO CENTRAL WISCONSIN. .DAY ONE...TODAY AND TONIGHT A LOW PRESSURE SYSTEM AND ACCOMPANYING COLD FRONT WILL MOVE EAST ACROSS THE AREA TODAY INTO THIS EVENING. THUNDERSTORMS WILL FIRE ALONG THE FRONT...WITH INSTABILITY AND WIND PROFILES FAVORING STORM ORGANIZATION. STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE...WITH DAMAGING WINDS AND LARGE HAIL THE MAIN THREATS. THE COLD FRONT WILL MOVE EAST OF THE AREA OVERNIGHT...SHIFTING THE THREAT FOR SEVERE THUNDERSTORMS OUT OF THE AREA. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THUNDERSTORMS ARE ALSO POSSIBLE LATE MONDAY NIGHT AND TUESDAY. IT IS TOO EARLY TO DETERMINE IF THERE WOULD BE A SEVERE WEATHER THREAT WITH THIS THUNDERSTORM POTENTIAL. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED BETWEEN 3 PM AND 9 PM. .EMERGENCY MANAGEMENT COORDINATION... NO CALL IS SCHEDULED. WETENKAMP
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE LA CROSSE WI 1248 PM CDT FRI AUG 20 2010 MNZ079-086-087-201845- DODGE-OLMSTED-WABASHA- 1248 PM CDT FRI AUG 20 2010 ...STRONG THUNDERSTORMS EXPECTED... AT 1246 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM NEAR BYRON...MOVING NORTHEAST AT 40 MPH. PEA SIZE HAIL...WINDS UP TO 50 MPH...OCCASIONAL CLOUD TO GROUND LIGHTNING...BRIEF HEAVY DOWNPOURS...ARE POSSIBLE WITH THIS STORM. * THE THUNDERSTORM WILL BE NEAR... ORONOCO BY 1255 PM CDT... MAZEPPA BY 105 PM CDT... LAKE CITY BY 130 PM CDT... GUSTY WINDS MAY CAUSE SMALL BRANCHES TO BE BLOWN DOWN...AND LOOSE OBJECTS TO BLOW AROUND. STAY AWAY FROM HIGH OBJECTS OUTDOORS SUCH AS TREES. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THIS STORM HAS PASSED. HALBACH
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE LA CROSSE WI 105 PM CDT FRI AUG 20 2010 IAZ009>011-019-029-030-MNZ079-087-088-094>096-WIZ032>034-041-053- 201830- ALLAMAKEE-BUFFALO-CHICKASAW-CLAYTON-FAYETTE-FILLMORE-HOUSTON-HOWARD- JACKSON-LA CROSSE-MOWER-OLMSTED-TREMPEALEAU-VERNON-WABASHA-WINNESHIEK-WINONA- 105 PM CDT FRI AUG 20 2010 ...STRONG THUNDERSTORMS BUILDING AND MOVING TOWARDS THE MISSISSIPPI RIVER... SCATTERED THUNDERSTORMS WERE MOVING ACROSS PARTS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA EARLY THIS AFTERNOON. SOME OF THE STRONGER STORMS WILL PRODUCE LOCALLY HEAVY RAIN...GUSTY WINDS AND A THREAT FOR LIGHTNING. MOVE INDOORS WHEN THESE STORMS PASS THROUGH. A QUICK QUARTER INCH OF RAIN IS POSSIBLE BUT FLOODING IS NOT EXPECTED WITH ANY OF THESE STORMS. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THESE STORMS HAVE PASSED. SHEA
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE LA CROSSE WI 131 PM CDT FRI AUG 20 2010 IAZ010-011-029-MNZ079-088-095-096-WIZ032>034-041-053-054-201930- ALLAMAKEE-BUFFALO-CRAWFORD-FAYETTE-FILLMORE-HOUSTON-JACKSON- LA CROSSE-TREMPEALEAU-VERNON-WABASHA-WINNESHIEK-WINONA- 131 PM CDT FRI AUG 20 2010 ...STRONG THUNDERSTORMS EXPECTED THROUGH MID-AFTERNOON... AT 125 PM...RADAR SHOWED SCATTERED THUNDERSTORMS OVER PARTS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA...EAST OF ROCHESTER MINNESOTA AND CHARLES CITY IOWA. THESE STORMS CONTINUED TO MOVE NORTHEAST AND WILL PRODUCE LOCALLY HEAVY RAIN...GUSTY WINDS AND A LIGHTNING RISK. THEY WILL BEGIN CROSSING INTO WESTERN WISCONSIN BY 2 PM AND BECOME MORE NUMEROUS PERHAPS. MOVE INDOORS AS THESE STORMS PASS OR TO A PLACE OF SHELTER. SHEA
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
236 PM CDT FRI AUG 20 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0236 PM TSTM WND GST LA CROSSE 43.83N 91.23W
08/20/2010 M40 MPH LA CROSSE WI AMATEUR RADIO
&&
DAVISSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE LA CROSSE WI 236 PM CDT FRI AUG 20 2010 IAZ011-030-MNZ096-WIZ029-034-041>043-053>055-061-202030- ALLAMAKEE-CLARK-CLAYTON-CRAWFORD-GRANT-HOUSTON-JACKSON-JUNEAU- LA CROSSE-MONROE-RICHLAND-VERNON- 236 PM CDT FRI AUG 20 2010 ...STRONG THUNDERSTORMS MOVING INTO WESTERN WISCONSIN... SCATTERED THUNDERSTORMS WERE OVER PARTS OF NORTHEAST IOWA... FAR SOUTHEAST MINNESOTA AND NOW INTO WESTERN WISCONSIN. THESE STORMS WILL CONTINUE TO TRACK NORTHEAST AND MAY PRODUCE OCCASIONAL GUSTY WINDS...HEAVY RAIN AND A LIGHTNING RISK. AT TIMES...A SEVERE THUNDERSTORM IS POSSIBLE WITH WIND GUSTS OF 60 MPH. MOVE INDOORS WHEN STORMS PASS THROUGH YOUR AREA. A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 800 PM FRIDAY EVENING FOR WESTERN WISCONSIN. SHEA
The La Crosse radar (KARX), 8 km away, was scanning. The volume nearest the first event began at 19:41 UTC.
1 thunderstorm wind. Local standard time, as filed.
A few trees were blown down northeast of Hokah.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2010Every state in 2010This day in weather historyWarnings in Minnesota, 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: 251806.