Tornado Watch 243

Issued

May 1, 2008, 4:34 PM CDT (21:34 UTC)

Expired

May 1, 2008, 9:47 PM CDT

In force

5 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

The Sioux Falls radar (KFSD), 50 km from the middle of the area, began a volume at 21:35 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

40%

One or more EF2 to EF5 tornadoes

20%

Ten or more severe wind reports

30%

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

70%

• Mesoscale Discussion 756May 1, 3:28 PM CDT
• Mesoscale Discussion 759May 1, 6:33 PM CDT
• Mesoscale Discussion 762May 1, 7:47 PM CDT

000
WWUS20 KWNS 012135
SEL3  
SPC WW 012135
IAZ000-MNZ000-SDZ000-020400-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 243
NWS STORM PREDICTION CENTER NORMAN OK
435 PM CDT THU MAY 1 2008

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

       PARTS OF NORTHWEST IOWA
       PARTS OF SOUTHWESTERN MINNESOTA
       LARGE PART OF SOUTHEASTERN SOUTH DAKOTA

EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 435 PM UNTIL
1100 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 60 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 45 MILES WEST SOUTHWEST OF
HURON SOUTH DAKOTA TO 35 MILES EAST SOUTHEAST OF SPENCER IOWA. 
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU3).

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...STRONG SELY FLOW E OF DEEP SFC LOW JUST S OF
YKN...RESULTING IN AN INCREASINGLY MOIST/UNSTABLE AIR MASS MOVING
NWWD THRU WATCH AREA.  THUNDERSTORMS WILL DEVELOP VICINITY COLD
FRONT THAT IS MOVING EWD THRU ERN NEB AND MOVE NWD THRU THE WATCH
AREA.  STRONG VEERING SHEAR PROFILES SUPPORT SUPERCELLS INCLUDING
TORNADOES AND LARGE HAIL.

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
500. MEAN STORM MOTION VECTOR 19025.


...HALES

Tornado Watches in South Dakota, 2008Tornado Watches in Iowa, 2008Tornado Watches in Minnesota, 2008Every tornado watch in 2008

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.