Tornado Watch 668

Issued

Oct 17, 2012, 7:01 PM CDT (00:01 UTC)

Expired

Oct 18, 2012, 3:00 AM CDT

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

1.5 in

Strongest gust expected

60 kt

The Shreveport radar (KSHV), 186 km from the middle of the area, began a volume at 00:04 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

50%

One or more EF2 to EF5 tornadoes

30%

Ten or more severe wind reports

80%

One or more gusts of 65 knots or more

20%

Ten or more severe hail reports

30%

One or more hailstones of 2 inches or more

20%

Six or more combined severe hail and wind reports

95%

• Mesoscale Discussion 2065Oct 17, 3:44 PM CDT
• Mesoscale Discussion 2067Oct 17, 6:29 PM CDT
• Mesoscale Discussion 2068Oct 17, 7:35 PM CDT
• Mesoscale Discussion 2070Oct 17, 9:28 PM CDT
• Mesoscale Discussion 2072Oct 17, 11:49 PM CDT
• Mesoscale Discussion 2075Oct 18, 2:40 AM CDT

256 
WWUS20 KWNS 180002
SEL8
SPC WW 180002
ARZ000-LAZ000-MSZ000-TXZ000-180800-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 668
NWS STORM PREDICTION CENTER NORMAN OK
700 PM CDT WED OCT 17 2012

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

       SOUTHERN ARKANSAS
       NORTHERN AND CENTRAL LOUISIANA
       CENTRAL MISSISSIPPI
       NORTHEAST TEXAS

EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 700 PM
UNTIL 300 AM CDT.

TORNADOES...HAIL TO 1.5 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 145 STATUTE
MILES EAST AND WEST OF A LINE FROM 30 MILES NORTH NORTHEAST OF
GREENVILLE MISSISSIPPI TO 45 MILES EAST SOUTHEAST OF NATCHITOCHES
LOUISIANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).

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 666...WW 667...

DISCUSSION...TSTMS...INCLUDING A FEW SUPERCELLS...EXPECTED TO
DEVELOP SWD ALONG AND AHEAD OF NE-SW COLD FRONT NOW APPROACHING THE
ARKLATEX AS ASSOCIATED ERN OK SHORTWAVE TROUGH FURTHER AMPLIFIES ESE
ACROSS REGION. THE STRONGEST/LONGEST-LIVED STORMS WITH THE GREATEST
TORNADO RISK ARE EXPECTED ALONG NE-SW CONFLUENCE AXIS NOW EXTENDING
FROM JUST E OF SHREVEPORT TO E OF LITTLE ROCK. STORMS WILL BE
FAST-MOVING AND ULTIMATELY MAY OUT-RUN LOW-LVL MOIST AXIS IN ERN MS
EARLY THU. BUT WIND PROFILES AND KINEMATIC ENVIRONMENT SUGGEST GOOD
LIKELIHOOD FOR SUBSTANTIAL MID-LVL STORM ROTATION. THUS...SVR
RISK/TORNADO POTENTIAL MAY EXTEND A BIT E OF THE MORE
SLOWLY-ADVANCING MOIST AXIS IN MS.

AVIATION...TORNADOES AND 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
500. MEAN STORM MOTION VECTOR 29035.


...CORFIDI

Tornado Watches in Mississippi, 2012Tornado Watches in Louisiana, 2012Tornado Watches in Arkansas, 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.