Tornado Watch: 10 PM. NOAA SPC has issued a watch for much of southwest, west central and central Minnesota, including the far western suburbs of the Twin Cities, St. Cloud and Willmar, until 10 pm. With a nagging frontal boundary from near Watertown to Mankato there may be enough low-level wind shear for a few large tornadoes into the evening hours, especially southwestern Minnesota. Details from SPC:
URGENT - IMMEDIATE BROADCAST REQUESTED TORNADO WATCH NUMBER 336 NWS STORM PREDICTION CENTER NORMAN OK 200 PM CDT FRI JUN 21 2013 THE NWS STORM PREDICTION CENTER HAS ISSUED A * TORNADO WATCH FOR PORTIONS OF NORTHWEST IOWA SOUTHWEST INTO CENTRAL MINNESOTA EASTERN SOUTH DAKOTA * EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 200 PM UNTIL 1000 PM CDT. * PRIMARY THREATS INCLUDE... SEVERAL TORNADOES POSSIBLE NUMEROUS DAMAGING WIND GUSTS LIKELY WITH A FEW SIGNIFICANT GUSTS TO 80 MPH POSSIBLE SEVERAL LARGE HAIL EVENTS LIKELY WITH A FEW VERY LARGE HAIL EVENTS TO 3 INCHES IN DIAMETER POSSIBLE THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 100 STATUTE MILES EAST AND WEST OF A LINE FROM 20 MILES EAST NORTHEAST OF ALEXANDRIA MINNESOTA TO 50 MILES SOUTHWEST OF SIOUX FALLS SOUTH DAKOTA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS. OTHER WATCH INFORMATION...CONTINUE...WW 335... DISCUSSION...UPSCALE CONVECTIVE GROWTH IS EXPECTED TO PERSIST WITH THE CONTINUED EVOLUTION OF A SEVERE MESOSCALE CONVECTIVE SYSTEM ACROSS EASTERN SOUTH DAKOTA INTO SOUTHWEST AND CENTRAL MINNESOTA...AND PARTS OF ADJACENT NORTHWEST IOWA...LATE THIS AFTERNOON AND EVENING. IN THE PRESENCE OF THERMODYNAMIC PROFILES CHARACTERIZED BY STEEP MID-LEVEL LAPSE RATES AND LARGE CAPE...VERTICAL SHEAR WILL BE SUFFICIENT TO SUPPORT THE RISK FOR VERY LARGE HAIL AND LOCALLY STRONG WIND GUSTS NEAR STRONGEST STORMS. A COUPLE OF TORNADOES ARE ALSO POSSIBLE ALONG THE REMNANT BAROCLINIC ZONE ASSOCIATED WITH CONVECTIVE OUTFLOW GENERATED BY EARLY MORNING CONVECTION. AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM MOTION VECTOR 24035.