Tornado Watch 661

Issued

Oct 13, 2012, 1:00 PM CDT (18:00 UTC)

Expired

Oct 13, 2012, 9:00 PM CDT

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

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

60%

One or more hailstones of 2 inches or more

30%

Six or more combined severe hail and wind reports

95%

• Mesoscale Discussion 2045Oct 13, 12:23 PM CDT
• Mesoscale Discussion 2048Oct 13, 2:55 PM CDT
• Mesoscale Discussion 2052Oct 13, 6:59 PM CDT

466 
WWUS20 KWNS 131804
SEL1
SPC WW 131804
OKZ000-TXZ000-140200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 661
NWS STORM PREDICTION CENTER NORMAN OK
100 PM CDT SAT OCT 13 2012

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

       WESTERN AND CENTRAL OKLAHOMA
       NORTHWEST TEXAS

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 100 PM UNTIL
900 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 65 STATUTE
MILES EAST AND WEST OF A LINE FROM 45 MILES EAST NORTHEAST OF
ALVA OKLAHOMA TO 20 MILES SOUTH SOUTHWEST OF ABILENE TEXAS.  FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU1).

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...THUNDERSTORM DEVELOPMENT IS LIKELY IN THE NEXT COUPLE
OF HOURS FROM NW TX INTO WRN OK...ALONG AND JUST E OF THE SURFACE
COLD FRONT.  A NARROW ZONE OF SURFACE HEATING  TO THE W OF THE
ONGOING CONVECTION FROM N TX INTO CENTRAL OK...AND BOUNDARY LAYER
DEWPOINTS IN THE UPPER 60S...ARE SUPPORTING MLCAPE NEAR 2000 J/KG.
DEEP-LAYER AND LOW-LEVEL VERTICAL SHEAR ARE FAVORABLE FOR
SUPERCELLS...AND THE CONVECTIVE MODE SHOULD BE A MIX OF
SEMI-DISCRETE CELLS AND LINE SEGMENTS THROUGH THE AFTERNOON.  A FEW
TORNADOES WILL BE POSSIBLE WITH THE MORE DISCRETE STORMS THROUGH THE
AFTERNOON/EVENING...ALONG WITH LARGE HAIL.  DAMAGING WINDS WILL
BECOME MORE OF A THREAT LATER AS STORMS POTENTIALLY EVOLVE INTO A
MORE SOLID LINE CLOSER TO I-35 IN OK.

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 24035.


...THOMPSON

Tornado Watches in Oklahoma, 2012Tornado Watches in Texas, 2012Every tornado 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.