Severe Thunderstorm Watch 683

Issued

Dec 17, 2012, 12:26 PM EST (17:26 UTC)

Expired

Dec 17, 2012, 6:44 PM EST

In force

6 hr

Issued by

the Storm Prediction Center

Largest hail expected

1.5 in

Strongest gust expected

60 kt

The Louisville radar (KLVX), 44 km from the middle of the area, began a volume at 17:29 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

10%

Ten or more severe wind reports

40%

One or more gusts of 65 knots or more

10%

Ten or more severe hail reports

95%

One or more hailstones of 2 inches or more

30%

Six or more combined severe hail and wind reports

95%

• Mesoscale Discussion 2170Dec 17, 12:03 PM EST
• Mesoscale Discussion 2171Dec 17, 1:58 PM EST
• Mesoscale Discussion 2172Dec 17, 2:24 PM EST
• Mesoscale Discussion 2175Dec 17, 4:42 PM EST

226 
WWUS20 KWNS 171730
SEL3  
SPC WW 171730
INZ000-KYZ000-TNZ000-180100-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 683
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM EST MON DEC 17 2012

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

       SOUTHERN INDIANA
       WESTERN...CENTRAL...AND EASTERN KENTUCKY
       MIDDLE TENNESSEE

EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 1230 PM UNTIL
800 PM EST.

HAIL TO 1.5 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 90
STATUTE MILES EAST AND WEST OF A LINE FROM 55 MILES NORTH OF
LEXINGTON KENTUCKY TO 25 MILES SOUTH OF NASHVILLE TENNESSEE.  FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU3).

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.

DISCUSSION...SHOWERS/TSTMS ARE BEGINNING TO FORM ALONG AND E OF
SSW-NNE CONFLUENCE ZONE NOW OVER WRN KY/TN. ACTIVITY LIKELY IS BEING
FOSTERED BY SFC HEATING AND MID LVL COLD ADVECTION/ASCENT DOWNSTREAM
FROM LEAD UPR IMPULSE NOW OVER SE MO...AND UPSTREAM DISTURBANCE IN
WRN MO. AMPLE DEEP SHEAR IS PRESENT FOR SUPERCELLS AND SUSTAINED
STORMS WITH SVR HAIL AND POSSIBLY LOCALLY DMGG WIND. A TORNADO OR
TWO CANNOT BE RULED OUT...ESPECIALLY WITH ANY LONGER-LIVED DISCRETE
STORMS IN SRN HALF OF WW...BUT RELATIVELY WEAK/VEERED LOW-LVL FLOW
SHOULD LIMIT SUCH THREAT.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 400. MEAN STORM
MOTION VECTOR 26035.


...CORFIDI

Severe Thunderstorm Watches in Kentucky, 2012Severe Thunderstorm Watches in Tennessee, 2012Severe Thunderstorm Watches in Indiana, 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.