During the early evening of July 1 around 7 pm, a line of showers and thunderstorms formed over south central Minnesota and north central Iowa. These storms were initially on a cold front. However, the storms over south central Minnesota began racing east ahead of the front, into the hot and humid airmass that was over the Upper Mississippi River Valley region. The result of this was numerous reports of severe wind gusts as well as wind damage across much of southeast Minnesota into southwest into central Wisconsin. A few reports of wind damage were also received in northeast Iowa. What was most interesting about this severe weather event was that even though the storms were weakening as they tracked east through the region, they still produced plenty of severe weather. The cause of the weakening was a combination of temperatures cooling through the evening and the environment turning less favorable for storms to organize over Wisconsin. Nevertheless, severe wind gusts and wind damage occurred into areas as far east as Sparta, Tomah, Necedah and Big Flats in the Upper Mississippi River Valley region.
The following is a summary of reports received into the National Weather Service in La Crosse as of 1238 am July 2nd:
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON... ..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.... ..REMARKS.. 0847 PM TSTM WND GST HAYFIELD 43.89N 92.85W 07/01/2011 E50.00 MPH DODGE MN FIRE DEPT/RESCUE 0902 PM TSTM WND GST HAYFIELD 43.89N 92.85W 07/01/2011 E60.00 MPH DODGE MN AMATEUR RADIO 0909 PM TSTM WND GST 5 S ROCHESTER 43.94N 92.48W 07/01/2011 M58.00 MPH OLMSTED MN ASOS 0910 PM TSTM WND GST 3 SW PLAINVIEW 44.13N 92.21W 07/01/2011 M66.00 MPH WABASHA MN AMATEUR RADIO 0916 PM TSTM WND GST ELGIN 44.13N 92.25W 07/01/2011 M60.00 MPH WABASHA MN AMATEUR RADIO 0930 PM TSTM WND DMG AUSTIN 43.67N 92.97W 07/01/2011 MOWER MN BROADCAST MEDIA A COUPLE OF 6-8 INCH IN DIAMETER TREES DOWN ON SOUTHEAST SIDE OF TOWN. 0942 PM TSTM WND DMG LEWISTON 43.98N 91.87W 07/01/2011 WINONA MN LAW ENFORCEMENT TREE BLOWN DOWN 0942 PM TSTM WND GST 2 W SPRING VALLEY 43.69N 92.43W 07/01/2011 M55.00 MPH FILLMORE MN TRAINED SPOTTER 0945 PM TSTM WND GST 6 W STEWARTVILLE 43.86N 92.61W 07/01/2011 E50.00 MPH OLMSTED MN PUBLIC 0956 PM TSTM WND GST 2 SE EYOTA 43.97N 92.20W 07/01/2011 M63.00 MPH OLMSTED MN MESONET 0958 PM TSTM WND GST 5 W PRESTON 43.67N 92.18W 07/01/2011 M72.00 MPH FILLMORE MN AWOS 1002 PM TSTM WND DMG OSSEO 44.58N 91.22W 07/01/2011 TREMPEALEAU WI LAW ENFORCEMENT POWER LINES DOWN 1006 PM HAIL 4 W OSAGE 43.28N 92.89W 07/01/2011 E0.50 INCH MITCHELL IA LAW ENFORCEMENT 1006 PM TSTM WND DMG 2 W ST. ANSGAR 43.38N 92.96W 07/01/2011 MITCHELL IA LAW ENFORCEMENT LARGE TREE DOWN 1006 PM TSTM WND DMG 2 S LYLE 43.48N 92.94W 07/01/2011 MITCHELL IA LAW ENFORCEMENT LARGE TREE DOWN 1014 PM TSTM WND GST GALESVILLE 44.08N 91.36W 07/01/2011 E50.00 MPH TREMPEALEAU WI NWS EMPLOYEE 1015 PM TSTM WND GST 4 NW HOKAH 43.80N 91.41W 07/01/2011 M61.00 MPH HOUSTON MN CO-OP OBSERVER 1017 PM TSTM WND DMG OSAGE 43.28N 92.81W 07/01/2011 MITCHELL IA LAW ENFORCEMENT A FEW TREES BLOWN DOWN 1020 PM TSTM WND DMG ALMA CENTER 44.44N 90.91W 07/01/2011 JACKSON WI LAW ENFORCEMENT TREES AND POWER LINES DOWN. 1022 PM TSTM WND DMG DAKOTA 43.91N 91.36W 07/01/2011 WINONA MN LAW ENFORCEMENT TREE BLOWN DOWN 1022 PM TSTM WND DMG HOKAH 43.76N 91.35W 07/01/2011 HOUSTON MN EMERGENCY MNGR TREES DOWN IN TOWN 1022 PM TSTM WND GST GRAND MEADOW 43.71N 92.57W 07/01/2011 E75.00 MPH MOWER MN BROADCAST MEDIA 1027 PM BLIZZARD LA CRESCENT 43.83N 91.30W 07/01/2011 HOUSTON MN EMERGENCY MNGR TREES AND POWER LINES DOWN. 1030 PM TSTM WND DMG LA CROSSE 43.83N 91.23W 07/01/2011 LA CROSSE WI LAW ENFORCEMENT TREE DOWN IN COPELAND PARK 1030 PM TSTM WND DMG 3 N LA CROSSE 43.87N 91.23W 07/01/2011 LA CROSSE WI PUBLIC NUMEROUS TREES SNAPPED OFF AND UPROOTED ALONG THE SHORELINE OF LAKE ONALASKA. ESTIMATED WIND GUSTS OF 70 MPH. 1030 PM TSTM WND DMG ONALASKA 43.89N 91.22W 07/01/2011 LA CROSSE WI PUBLIC A COUPLE OF TREES AND SEVERAL LIMBS DOWN ON THE NORTHWEST SIDE OF TOWN. 1031 PM TSTM WND GST 1 E LA CROSSE 43.83N 91.21W 07/01/2011 E49.00 MPH LA CROSSE WI MESONET 1033 PM TSTM WND GST 2 S LA CROSSE 43.80N 91.23W 07/01/2011 M56.00 MPH LA CROSSE WI AMATEUR RADIO SOME BRANCHES BLOWN OFF TREES. 1033 PM TSTM WND GST ONALASKA 43.89N 91.22W 07/01/2011 E60.00 MPH LA CROSSE WI TRAINED SPOTTER 1042 PM NON-TSTM WND GST 5 NNE STODDARD 43.73N 91.18W 07/01/2011 E50.00 MPH LA CROSSE WI NWS EMPLOYEE 1045 PM TSTM WND DMG 3 W NEILLSVILLE 44.56N 90.65W 07/01/2011 CLARK WI EMERGENCY MNGR TREE BLOWN DOWN ON VEHICLE. 1050 PM HAIL NORA SPRINGS 43.14N 93.01W 07/01/2011 E0.50 INCH FLOYD IA LAW ENFORCEMENT 1055 PM TSTM WND DMG SPARTA 43.94N 90.81W 07/01/2011 MONROE WI EMERGENCY MNGR NUMEROUS TREE LIMBS DOWN AROUND TOWN AND ALSO SOME ROOF DAMAGE TO A FEW BUILDINGS. 1055 PM TSTM WND GST 2 E LOYAL 44.74N 90.46W 07/01/2011 E55.00 MPH CLARK WI TRAINED SPOTTER 1059 PM TSTM WND DMG SPARTA 43.94N 90.81W 07/01/2011 MONROE WI AMATEUR RADIO LARGE TREE BLOWN DOWN AND SOME ROOF DAMAGE TO BUILDING ON WATER STREET. 1136 PM LIGHTNING WINONA 44.05N 91.66W 07/01/2011 WINONA MN LAW ENFORCEMENT HOUSE STRUCK BY LIGHTNING 1140 PM TSTM WND DMG FINLEY 44.22N 90.13W 07/01/2011 JUNEAU WI BROADCAST MEDIA TREES DOWN ALONG HWY 80 AND COUNTY ROAD F 1142 PM TSTM WND GST 5 E NECEDAH 44.02N 89.97W 07/01/2011 M63.00 MPH ADAMS WI TRAINED SPOTTER 1145 PM TSTM WND DMG 1 N NECEDAH 44.04N 90.07W 07/01/2011 JUNEAU WI LAW ENFORCEMENT SEVERAL TREES DOWN ACROSS HIGHWAY 21 NORTH OF NECEDAH. 1152 PM TSTM WND GST BIG FLATS 44.12N 89.80W 07/01/2011 E60.00 MPH ADAMS WI PUBLIC