Tornado Watch 75

Issued

Mar 25, 2007, 2:54 PM CDT (19:54 UTC)

Expired

Mar 25, 2007, 8:44 PM CDT

In force

6 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

The Minneapolis radar (KMPX), 116 km from the middle of the area, began a volume at 19:54 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

60%

One or more EF2 to EF5 tornadoes

30%

Ten or more severe wind reports

60%

One or more gusts of 65 knots or more

30%

Ten or more severe hail reports

50%

One or more hailstones of 2 inches or more

30%

Six or more combined severe hail and wind reports

90%

• Mesoscale Discussion 339Mar 25, 1:48 PM CDT
• Mesoscale Discussion 343Mar 25, 5:57 PM CDT

000
WWUS20 KWNS 252001
SEL5  
SPC WW 252001
IAZ000-MNZ000-WIZ000-260300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 75
NWS STORM PREDICTION CENTER NORMAN OK
255 PM CDT SUN MAR 25 2007

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       NORTHEAST IOWA
       EAST CENTRAL AND SOUTHEAST MINNESOTA
       WEST CENTRAL AND SOUTHWEST WISCONSIN

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 255 PM UNTIL
1000 PM CDT.

TORNADOES...HAIL TO 2 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 75 STATUTE
MILES EAST AND WEST OF A LINE FROM 85 MILES NORTH OF EAU CLAIRE
WISCONSIN TO 60 MILES EAST SOUTHEAST OF MASON CITY IOWA.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU5).

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.

DISCUSSION...A MID LEVEL TROUGH CONTINUES TO MOVE EWD OVER W/SW
MN...WHILE SURFACE HEATING/DESTABILIZATION HAS PROGRESSED THROUGH
THE AFTERNOON IN THE WARM SECTOR IN ADVANCE OF THIS SYSTEM.  IT
APPEARS THAT CONVECTIVE INHIBITION IS WEAKENING AND THUNDERSTORM
INITIATION IS EXPECTED BY 21-22Z ALONG A SURFACE TROUGH ACROSS NRN
IA INTO SRN MN.  SURFACE TEMPERATURES IN THE MID-UPPER 70S AND
DEWPOINTS IN THE MID-UPPER 50S ARE CONTRIBUTING TO MLCAPE VALUES
APPROACHING 1000 J/KG...AND LOCAL PROFILERS/VWPS SHOW FAVORABLE
VERTICAL SHEAR FOR SUPERCELLS.  THE INITIAL CONVECTION SHOULD TAKE
THE FORM OF DISCRETE SUPERCELLS CAPABLE OF PRODUCING LARGE HAIL AND
DAMAGING WINDS...THOUGH CONVECTION MAY GROW INTO A MORE LINEAR MCS
BY LATE EVENING INTO WI.  RELATIVELY LARGE TEMPERATURE-DEWPOINT
SPREADS COULD TEMPER THE TORNADO THREAT SOMEWHAT INITIALLY...BUT THE
ENVIRONMENT STILL APPEARS SUPPORTIVE OF A FEW TORNADOES NEAR AND E
OF THE MS RIVER LATE THIS AFTERNOON INTO THIS EVENING.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
450. MEAN STORM MOTION VECTOR 24045.


...THOMPSON

Tornado Watches in Wisconsin, 2007Tornado Watches in Minnesota, 2007Tornado Watches in Iowa, 2007Every tornado watch in 2007

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.