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IAZ000-MNZ000-WIZ000-160400-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 178

NWS STORM PREDICTION CENTER NORMAN OK

340 PM CDT SUN APR 15 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       EXTREME NORTHERN IOWA

       SOUTHERN MINNESOTA

       WEST CENTRAL WISCONSIN



EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 340 PM UNTIL

1100 PM CDT.



TORNADOES...HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 85 STATUTE

MILES EITHER SIDE OF A LINE FROM 50 MILES SOUTH SOUTHWEST OF

REDWOOD FALLS MINNESOTA TO 40 MILES EAST SOUTHEAST OF EAU CLAIRE

WISCONSIN.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).



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 177...



DISCUSSION...STORMS ARE STARTING TO INCREASE FROM NWRN IA INTO SWRN

MN IN ADVANCE OF A STRONG UPPER TROUGH/VORTICITY MAX MOVING NEWD

TOWARD THE UPPER MS VALLEY.  AIR MASS ALONG AND SOUTH OF THE WARM

FRONT EXTENDING ACROSS SRN MN INTO WRN WI HAS WARMED DURING THE

AFTERNOON RESULTING IN MLCAPE OF 1000-1500 J/KG.  VERY STRONG WINDS

ALOFT AND ASSOCIATED INTENSE VERTICAL SHEAR WILL AID IN STORM

ORGANIZATION WITH POTENTIAL FOR SUPERCELLS TO DEVELOP...ESPECIALLY

AS STORMS INTERACT WITH THE WARM FRONT.  LARGE HAIL...DAMAGING WINDS

AND A FEW TORNADOES WILL BE POSSIBLE WITH STRONGER CELLS AS ACTIVITY

GRADUALLY SPREADS/DEVELOPS NEWD THROUGH THE EVENING HOURS.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

500. MEAN STORM MOTION VECTOR 21045.





...WEISS

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