Severe Thunderstorm Watch 241

Issued

May 4, 2012, 5:52 PM CDT (22:52 UTC)

Expired

May 4, 2012, 11:01 PM CDT

In force

5 hr

Issued by

the Storm Prediction Center

Largest hail expected

2.5 in

Strongest gust expected

60 kt

The Omaha radar (KOAX), 99 km from the middle of the area, began a volume at 22:52 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

20%

One or more EF2 to EF5 tornadoes

5%

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

40%

Six or more combined severe hail and wind reports

70%

• Mesoscale Discussion 698May 4, 3:52 PM CDT
• Mesoscale Discussion 700May 4, 5:31 PM CDT
• Mesoscale Discussion 706May 4, 9:54 PM CDT
• Mesoscale Discussion 708May 4, 10:55 PM CDT

781 
WWUS20 KWNS 042246
SEL1
SPC WW 042246
IAZ000-NEZ000-050500-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 241
NWS STORM PREDICTION CENTER NORMAN OK
550 PM CDT FRI MAY 4 2012

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

       EXTREME WEST CENTRAL AND SOUTHWEST IOWA
       CENTRAL AND EASTERN NEBRASKA

EFFECTIVE THIS FRIDAY AFTERNOON FROM 550 PM UNTIL MIDNIGHT CDT.

HAIL TO 2.5 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 45
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 35 MILES SOUTH OF
BURWELL NEBRASKA TO 35 MILES NORTH NORTHEAST OF SHENANDOAH IOWA.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU1).

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 238...WW 239...WW 240...

DISCUSSION...THUNDERSTORM COVERAGE/INTENSITY IS EXPECTED TO INCREASE
ALONG A SWD-MOVING OUTFLOW BOUNDARY ACROSS CENTRAL/ERN NEB THROUGH
LATE EVENING.  STRONG INSTABILITY IS PRESENT S OF THE BOUNDARY...AND
DEEP-LAYER VERTICAL SHEAR IS SUFFICIENT FOR SUPERCELLS.  LARGE HAIL
AND DAMAGING WINDS WILL BE THE PRIMARY THREATS GIVEN THE STEEP
LOW-MIDLEVEL LAPSE RATES ACROSS THE AREA.

AVIATION...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 550. MEAN STORM
MOTION VECTOR 30015.


...THOMPSON

Severe Thunderstorm Watches in Nebraska, 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.