Severe Thunderstorm Watch 247

Issued

May 5, 2012, 6:49 AM CDT (11:49 UTC)

Expired

May 5, 2012, 2:00 PM CDT

In force

7 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

The Sioux Falls radar (KFSD), 108 km from the middle of the area, began a volume at 11:52 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

10%

One or more EF2 to EF5 tornadoes

2%

Ten or more severe wind reports

20%

One or more gusts of 65 knots or more

10%

Ten or more severe hail reports

40%

One or more hailstones of 2 inches or more

20%

Six or more combined severe hail and wind reports

70%

• Mesoscale Discussion 712May 5, 9:50 AM CDT

575 
WWUS20 KWNS 051149
SEL7
SPC WW 051149
IAZ000-MNZ000-SDZ000-051800-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 247
NWS STORM PREDICTION CENTER NORMAN OK
650 AM CDT SAT MAY 5 2012

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

       NORTHWEST IOWA
       SOUTHWEST MINNESOTA
       SOUTHEAST SOUTH DAKOTA

EFFECTIVE THIS SATURDAY MORNING AND AFTERNOON FROM 650 AM UNTIL
100 PM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 55
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 25 MILES WEST
NORTHWEST OF CHAMBERLAIN SOUTH DAKOTA TO 25 MILES SOUTH SOUTHEAST
OF WORTHINGTON MINNESOTA.  FOR A COMPLETE DEPICTION OF THE WATCH
SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 245...WW 246...

DISCUSSION...ELEVATED TSTMS...INCLUDING SUSTAINED STORMS AND
POSSIBLY A COUPLE SUPERCELLS...EXPECTED TO MOVE/DEVELOP E TO ESE
ACROSS WW AREA THROUGH LATER THIS MORNING AS LOW LVL WAA/MOISTURE
TRANSPORT INCREASE AHEAD OF WEAK DISTURBANCES PRECEDING MAIN WRN
U.S. UPR TROUGH.  MAIN SVR THREAT SHOULD BE LARGE HAIL GIVEN SIZABLE
CLOUD LAYER SHEAR AND QUALITY OF ELEVATED MOISTURE INFLOW.

AVIATION...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 28025.


...CORFIDI

Severe Thunderstorm Watches in South Dakota, 2012Severe Thunderstorm Watches in Minnesota, 2012Severe Thunderstorm Watches in Iowa, 2012Every severe thunderstorm 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.