Tornado Watch 686

Issued

Dec 19, 2012, 7:36 PM CST (01:36 UTC)

Expired

Dec 20, 2012, 2:00 AM CST

In force

6 hr

Issued by

the Storm Prediction Center

Largest hail expected

1 in

Strongest gust expected

60 kt

The Western Arkansas radar (KSRX), 67 km from the middle of the area, began a volume at 01:38 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

40%

One or more gusts of 65 knots or more

10%

Ten or more severe hail reports

10%

One or more hailstones of 2 inches or more

5%

Six or more combined severe hail and wind reports

70%

• Mesoscale Discussion 2179Dec 19, 7:07 PM CST
• Mesoscale Discussion 2182Dec 19, 10:22 PM CST

073 
WWUS20 KWNS 200141
SEL6
SPC WW 200141
ARZ000-KSZ000-MOZ000-OKZ000-TXZ000-200800-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 686
NWS STORM PREDICTION CENTER NORMAN OK
735 PM CST WED DEC 19 2012

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

       WESTERN ARKANSAS
       EXTREME SOUTHEAST KANSAS
       SOUTHWEST MISSOURI
       EASTERN OKLAHOMA
       EXTREME NORTHEAST TEXAS

EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 735 PM
UNTIL 200 AM CST.

TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 70 STATUTE
MILES EAST AND WEST OF A LINE FROM 15 MILES NORTH NORTHEAST OF
SPRINGFIELD MISSOURI TO 5 MILES EAST SOUTHEAST OF PARIS TEXAS.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU6).

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...STORMS ARE INTENSIFYING ALONG A DRY LINE FROM SOUTH
CENTRAL OK INTO FAR NORTH-CENTRAL TX...WITH LESS-ORGANIZED
CONVECTION DEVELOPING OVER NERN OK.  STORMS ARE LIKELY TO INCREASE
TONIGHT AS A STRONG COLD FRONT OVERTAKES THE DRY LINE AND BEGINS TO
SURGE EWD ACROSS THE AREA.  STRONG DYNAMIC FORCING FOR ASCENT
ASSOCIATED WITH AN INTENSE UPPER TROUGH MOVING INTO THE CENTRAL
PLAINS WILL ENHANCE FORCED LIFT ALONG THE COLD FRONT SUPPORTIVE OF
ADDITIONAL STRONG/SEVERE STORM DEVELOPMENT.  STRENGTHENING WINDS
ALOFT/DEEP LAYER SHEAR AND CLOCKWISE TURNING LOW-LEVEL HODOGRAPHS
FAVOR EMBEDDED SUPERCELL/QLCS STRUCTURES WITH DAMAGING WINDS AND
SEVERAL TORNADOES POSSIBLE TONIGHT.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 400.
MEAN STORM MOTION VECTOR 23045.


...WEISS

Tornado Watches in Arkansas, 2012Tornado Watches in Oklahoma, 2012Tornado Watches in Missouri, 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; radar from the NEXRAD Level II archive.