Tornado Watch 180

Issued

Apr 22, 2011, 3:47 PM CDT (20:47 UTC)

Expired

Apr 23, 2011, 12:00 AM CDT

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

4 in

Strongest gust expected

60 kt

The Norman radar (KTLX), 101 km from the middle of the area, began a volume at 20:49 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

30%

One or more EF2 to EF5 tornadoes

20%

Ten or more severe wind reports

70%

One or more gusts of 65 knots or more

30%

Ten or more severe hail reports

95%

One or more hailstones of 2 inches or more

50%

Six or more combined severe hail and wind reports

95%

• Mesoscale Discussion 518Apr 22, 1:23 PM CDT
• Mesoscale Discussion 525Apr 22, 8:09 PM CDT
• Mesoscale Discussion 527Apr 22, 9:39 PM CDT
• Mesoscale Discussion 528Apr 22, 11:10 PM CDT

981 
WWUS20 KWNS 222046
SEL0
SPC WW 222046
ARZ000-OKZ000-230300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 180
NWS STORM PREDICTION CENTER NORMAN OK
350 PM CDT FRI APR 22 2011

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

       NORTHWEST ARKANSAS
       EASTERN OKLAHOMA

EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 350 PM UNTIL
1000 PM CDT.

TORNADOES...HAIL TO 4 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 25 MILES SOUTH OF ARDMORE
OKLAHOMA TO 40 MILES NORTH NORTHWEST OF FAYETTEVILLE ARKANSAS.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU0).

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 178...WW 179...

DISCUSSION...THUNDERSTORMS ARE EXPECTED TO RAPIDLY FORM ALONG COLD
FRONT ADVANCING SOUTHEASTWARD INTO EASTERN OK THIS EVENING.  OTHER
MORE ISOLATED STORMS ARE POSSIBLE SOUTHWARD ALONG THE DRYLINE NEAR
THE RED RIVER.  VERY UNSTABLE CONDITIONS /MLCAPE OVER 3500 J/KG/
ALONG WITH SUFFICIENT VERTICAL SHEAR WILL POSE A THREAT OF
SUPERCELLS CAPABLE OF VERY LARGE HAIL AND DAMAGING WINDS.  LOW LEVEL
VERTICAL SHEAR IS NOT PARTICULARLY STRONG...BUT SUFFICIENT GIVEN THE
DEGREE OF INSTABILITY TO WARRANT A THREAT OF ISOLATED TORNADOES.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 4 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
550. MEAN STORM MOTION VECTOR 27030.


...HART

Tornado Watches in Oklahoma, 2011Tornado Watches in Arkansas, 2011Every tornado watch in 2011

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.