Tornado Watch 178

Issued

Apr 15, 2012, 3:37 PM CDT (20:37 UTC)

Expired

Apr 15, 2012, 10:11 PM CDT

In force

7 hr

Issued by

the Storm Prediction Center

Largest hail expected

2.5 in

Strongest gust expected

60 kt

The Minneapolis radar (KMPX), 47 km from the middle of the area, began a volume at 20:39 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Two or more tornadoes

50%

One or more EF2 to EF5 tornadoes

20%

Ten or more severe wind reports

40%

One or more gusts of 65 knots or more

10%

Ten or more severe hail reports

30%

One or more hailstones of 2 inches or more

20%

Six or more combined severe hail and wind reports

70%

• Mesoscale Discussion 547Apr 15, 12:25 PM CDT
• Mesoscale Discussion 550Apr 15, 1:56 PM CDT
• Mesoscale Discussion 553Apr 15, 5:54 PM CDT
• Mesoscale Discussion 557Apr 15, 9:33 PM CDT

181 
WWUS20 KWNS 152040
SEL8  
SPC WW 152040
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

Tornado Watches in Minnesota, 2012Tornado Watches in Wisconsin, 2012Tornado Watches in Iowa, 2012Every tornado watch in 2012

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.