* First (Minnesota) tornado of the year touches down near Nashua (Wilkin county) around 4:40 pm Wednesday afternoon.
* At least 6 separate tornado touchdowns reported Wednesday.
* Large, violent tornado sweeps across Austin, Minnesota. This "multi-vortex" tornado (consisting of several separate tornado funnels are rotating around a common center/wall cloud) caused extensive damage, power outages, flipping cars, closing roads and triggering injuries, especially in the northern suburbs of Austin. We won't know the complete extent of damage until the sun comes up Thursday.
* Same frontal boundary lingers nearby Thursday - another slight/moderate threat of severe storms. I do expect watches/warnings by late afternoon.
* Computer models print out 1-2" of rain for many communities by Friday.
Update: 9:20 pm. Series of Doppler radar images showing severe rotation west of Stewartville. The image below shows a reflectivity display. Note the extreme wind shear causing the tornadic cell to "tilt" over to one side, to the right of the general motion of upper level winds (west/northwest or 290 degrees).
Tornado watch for much of southern MN (does NOT include Twin Cities) until 1 am Thursday morning. At least 6 tornado touchdowns in Minnesota (as of 9:00 pm). The most notable: large, violent tornado hits the Austin area with reports of damage & injuries, possibly a "multi-vortex" tornado with multiple funnels rotating around a common center/wall cloud. The lingering threat is greatest east of Owatonna and Austin, toward Stewartville, Rochester, Cannon Falls and the Winona area. Residents of far southeastern MN should stay alert and stay tuned for possible warnings.
(Click on the image to bring it full screen and read the tornado warning text for the Owatonna area).
Update: 9:00 pm. Reports of a large, damaging tornado in the Austin area, and the threat is not over yet. Cars have been flipped over in the Austin area with injury reports and considerable debris. Power is out throughout the city. A "multivortex" tornado (several tornadoes all spinning around a common center) was observed with this supercell thunderstorm. Tornadoes often form in "families", one tornado touches down, matures and then dies out. Minutes later the same parent thunderstorm spawns a second tornado farther south/east, in the warm, humid air, unaffected by rain/hail-cooled air. This process can continue for many hours, resulting in multiple tornadoes from the same supercell thunderstorm.
Update: 8:45 pm. Very worried about Owatonna area: Doppler storm relative velocity field showing very strong rotation directly over the town - supercell has a long history of producting tornadoes/funnel clouds.
Update: 8:30 pm. Funnel clouds spotted near Waseca.
* Greatest tornado risk: Austin area. Large tornado on the ground, impacting northern/eastern suburbs of Austin area!
* Tornado warnings posted for southeastern MN counties through the evening hours.
* Greatest risk near Owatonna, Faribault, Austin and Rochester/Stewartville area.
* Strong/severe storms may move into the Twin Cities metro area later tonight - conditions ripe.
* Computer models print out some 1-2" rainfall amounts over the next few days, potential for tropical dew points.
* First Minnesota tornado of the year touches down in Wilkin county (far west central MN) around 4:40 pm. No reports of injuries/damage.
8:34 pm (Greatest threat appears to be just east/northeast of Austin, tornadic supercell moving toward Elkton and Dexter area).
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
817 PM CDT WED JUN 17 2009
MNC099-180215-
/O.CON.KARX.TO.W.0009.000000T0000Z-090618T0215Z/
MOWER MN-
817 PM CDT WED JUN 17 2009
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 915 PM CDT FOR MOWER
COUNTY...
AT 814 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR AND STORM
SPOTTERS WERE TRACKING A LARGE AND EXTREMELY DANGEROUS TORNADO. THIS
TORNADO WAS LOCATED NEAR I 90 EXIT 181...OR NEAR AUSTIN...MOVING
SOUTHEAST AT 35 MPH. IT APPEARS THIS TORNADO WILL TRACK ACROSS THE
NORTH AND NORTHEAST SIDE OF AUSTIN.
IF YOU ARE IN THE PATH OF THIS STORM...YOU MUST GET INDOORS AND
UNDERGROUND IN A BASEMENT. DO NOT STOP UNDER HIGHWAY
OVERPASSES...SEEK SHELTER IN A BUILDING OFF THE HIGHWAY.
* THE TORNADO WILL BE NEAR...
I 90 EXIT 183 AND RENOVA AROUND 820 PM...
ROSE CREEK AND I 90 EXIT 187 AROUND 825 PM...
ADAMS AROUND 835 PM...
GRAND MEADOW AROUND 840 PM...
HIGHWAYS 63 AND 16 AROUND 850 PM...
PRECAUTIONARY/PREPAREDNESS ACTIONS...
CARS AND MOBILE HOMES SHOULD BE ABANDONED FOR A STURDY BUILDING. AS A
LAST RESORT...LAY FLAT IN A DITCH AND COVER YOUR HEAD.
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
817 PM CDT WED JUN 17 2009
MNC131-147-161-180130-
/O.CON.KMPX.TO.W.0008.000000T0000Z-090618T0130Z/
RICE MN-WASECA MN-STEELE MN-
817 PM CDT WED JUN 17 2009
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 830 PM CDT FOR NORTHERN
STEELE...NORTHEASTERN WASECA AND EXTREME SOUTHWESTERN RICE
COUNTIES...
AT 815 PM CDT...A FUNNEL CLOUD WAS REPORTED NORTHEAST OF WASECA.
AT 816 PM CDT... THE TORNADIC SEVERE THUNDERSTORM WAS LOCATED 5 MILES
EAST OF WASECA...OR ABOUT 6 MILES SOUTH OF DEERFIELD...AND MOVING
EAST AT 20 MPH.
THE TORNADO WILL BE NEAR...
OWATONNA BY 830 PM CDT...
PRECAUTIONARY/PREPAREDNESS ACTIONS...
IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER IN A NEARBY REINFORCED
BUILDING. AS A LAST RESORT...SEEK SHELTER IN A CULVERT...DITCH OR LOW
SPOT AND COVER YOUR HEAD WITH YOUR HANDS.
THE SAFEST PLACE TO BE DURING A TORNADO IS IN A BASEMENT. GET UNDER A
WORKBENCH OR OTHER PIECE OF STURDY FURNITURE. IF NO BASEMENT IS
AVAILABLE...SEEK SHELTER ON THE LOWEST FLOOR OF THE BUILDING IN AN
INTERIOR HALLWAY OR ROOM SUCH AS A CLOSET. USE BLANKETS OR PILLOWS TO
COVER YOUR BODY AND ALWAYS STAY AWAY FROM WINDOWS.
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