Stormy Weekend: August 7-8, 2009

Rainfall Map

It was a rainy weekend over parts of central and southern Minnesota. There were three rounds of rain. Below is a synopsis of the most stormy and rainy weekend of the year (so far) in the Twin Cities.

Round one, during the morning and early afternoon of Friday, August 7.

The first rain event was a thick band of showers and thunderstorms that moved from west to east across much of central and southern Minnesota during the morning and early afternoon hours on Friday. This band dropped anywhere from a half to over an inch of rain. The rain ended by early afternoon in the Twin Cities with some gusty southeast winds. In general this was a good soaking rain.

Round two, late Friday, August 7 to early morning hours of Saturday August 8.

The heaviest rain fell with strong thunderstorms that developed near a warm front draped over southern Minnesota around 10pm Friday, August 7. These storms moved tot he north east and formed an east to west line from Montevideo to the southern half of the Twin Cities. The storms then began drifting east and dropped torrential rains. This caused street flooding in spots including Shakopee. The highest 24 hour total was 6.20 inches in Chaska. This included 1.34 inches that fell in the first wave during the day on Friday, and the 4.86 inches for the late Friday into early Saturday. Other thunderstorms developed in the early morning hours on Saturday to the northwest of the Twin Cities and dumped heavy rain at St. Cloud. The heavy rains were most welcome to areas that were under a moderate or severe drought.

Round three, Saturday night, August 8

For the first time this summer, truly tropical air reached the Twin Cities. The dew point temperature slowly climbed throughout the afternoon on Saturday and was 75 degrees by 8pm, the highest so far for the Twin Cities in 2009. For a time it looked like the risk of severe weather had passed by the Twin Cities. Then at 7pm an tiny cluster of storms developed in Wright County. These storms rapidly intensified and moved east and north east. An EF1 tornado was reported in Minnetrista and moved northeast through Orono and Long Lake and ended over the southwest portion of Plymouth. By 11pm the storms had moved across the St. Croix River into Wisconsin.

The National Weather Service Office in Chanassen posted an story about about the tornadoes in Hennepin County and in West Central Wisconsin.

Below are Local Storm Reports on the August 7-8 storms courtesy the National Weather Service.


PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
216 AM CDT MON AUG 03 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0936 PM     HAIL             SEAFORTH                44.48N 95.33W
08/02/2009  M0.88 INCH       REDWOOD            MN   TRAINED SPOTTER

0936 PM     HAIL             3 SW LUCAN              44.38N 95.45W
08/02/2009  M1.00 INCH       REDWOOD            MN   TRAINED SPOTTER

0943 PM     HAIL             7 S OLIVIA              44.67N 95.00W
08/02/2009  M1.00 INCH       RENVILLE           MN   TRAINED SPOTTER

0948 PM     HAIL             5 SW OLIVIA             44.73N 95.06W
08/02/2009  M1.75 INCH       RENVILLE           MN   TRAINED SPOTTER

0950 PM     HAIL             1 S BIRD ISLAND         44.75N 94.89W
08/02/2009  M2.75 INCH       RENVILLE           MN   STORM CHASER

            GOLF BALL TO BASEBALL SIZED HAIL STILL COVERING GROUND AT
            1010 CDT PM.

1000 PM     HAIL             4 WSW CLEMENTS          44.35N 95.13W
08/02/2009  M1.00 INCH       REDWOOD            MN   TRAINED SPOTTER

1002 PM     HAIL             3 S CLEMENTS            44.34N 95.05W
08/02/2009  M0.88 INCH       REDWOOD            MN   TRAINED SPOTTER

1005 PM     HAIL             5 E OLIVIA              44.76N 94.90W
08/02/2009  M1.75 INCH       RENVILLE           MN   TRAINED SPOTTER

1008 PM     HAIL             2 NE HECTOR             44.76N 94.68W
08/02/2009  M2.00 INCH       RENVILLE           MN   TRAINED SPOTTER

1015 PM     HAIL             1 N SPRINGFIELD         44.25N 94.98W
08/02/2009  E1.00 INCH       BROWN              MN   CO-OP OBSERVER

1023 PM     HAIL             HUTCHINSON              44.89N 94.37W
08/02/2009  M0.75 INCH       MCLEOD             MN   TRAINED SPOTTER

1027 PM     HAIL             5 S HUTCHINSON          44.82N 94.37W
08/02/2009  M1.00 INCH       MCLEOD             MN   TRAINED SPOTTER

1036 PM     HAIL             E STEWART               44.72N 94.48W
08/02/2009  M1.00 INCH       MCLEOD             MN   TRAINED SPOTTER

1054 PM     HAIL             5 N BROWNTON            44.81N 94.35W
08/02/2009  M1.75 INCH       MCLEOD             MN   LAW ENFORCEMENT

1055 PM     FUNNEL CLOUD     2 SSE NORWOOD/YOUNG AME 44.75N 93.90W
08/02/2009                   CARVER             MN   TRAINED SPOTTER

1114 PM     HAIL             2 ENE NEW AUBURN        44.68N 94.19W
08/02/2009  M0.75 INCH       SIBLEY             MN   TRAINED SPOTTER

1223 AM     HAIL             ROBERTS                 44.99N 92.55W
08/03/2009  M1.00 INCH       ST. CROIX          WI   TRAINED SPOTTER