Tornado Watch 657

Issued

Sep 30, 2012, 5:50 PM CDT (22:50 UTC)

Expired

Oct 1, 2012, 2:00 AM CDT

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

1 in

Strongest gust expected

60 kt

The Jackson/Brandon,MS radar (KDGX), 90 km from the middle of the area, began a volume at 22:53 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

20%

One or more gusts of 65 knots or more

5%

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 2010Sep 30, 5:09 PM CDT
• Mesoscale Discussion 2011Sep 30, 9:48 PM CDT
• Mesoscale Discussion 2012Oct 1, 1:45 AM CDT

153 
WWUS20 KWNS 302300
SEL7
SPC WW 302300
ALZ000-FLZ000-LAZ000-MSZ000-CWZ000-010700-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 657
NWS STORM PREDICTION CENTER NORMAN OK
545 PM CDT SUN SEP 30 2012

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

       SOUTHWEST AND WEST CENTRAL ALABAMA
       FAR WESTERN FLORIDA PANHANDLE
       SOUTHEAST AND EASTERN LOUISIANA
       SOUTHERN AND SOUTH CENTRAL MISSISSIPPI
       COASTAL WATERS

EFFECTIVE THIS SUNDAY AFTERNOON AND MONDAY MORNING FROM 545 PM
UNTIL 200 AM CDT.

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 115 STATUTE
MILES EAST AND WEST OF A LINE FROM 45 MILES NORTH NORTHEAST OF
JACKSON MISSISSIPPI TO 70 MILES SOUTH SOUTHEAST OF MOBILE
ALABAMA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).

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...THIS TORNADO WATCH REPLACES TORNADO
WATCH NUMBER 656. WATCH NUMBER 656 WILL NOT BE IN EFFECT AFTER
545 PM CDT.

DISCUSSION...SCTD TSTMS EXPECTED TO CONTINUE FORMING THROUGH LATE
TNGT/EARLY MON ALONG N-S CONFLUENCE LINE MOVING SLOWLY EWD IN SE
QUADRANT OF SFC LOW NOW NEAR NATCHEZ MS. AREA VWP DATA /ESPECIALLY
AT MOB/ SUGGEST THAT BAND OF 35-40 KT SSWLY 700 MB WINDS THAT HAS
BEEN FCST TO MOVE NE ACROSS THE CNTRL GULF CST REGION THIS EVE
ALREADY IS IN THE PROCESS OF DOING SO. AS THE SPEED MAX CONTINUES
NEWD...ASSOCIATED STRENGTHENING OF LOW-LVL SHEAR MAY SUPPORT FURTHER
DEVELOPMENT OF OCCASIONAL LOW-LVL MESOS/POSSIBLE TORNADOES IN
SRN/ERN PORTIONS OF WW GIVEN RICH MOISTURE OVER REGION AND
LIKELIHOOD FOR DEVELOPMENT OF NEW UPDRAFTS IN MODERATE...SSELY
NEAR-SFC FLOW AHEAD OF CONFLUENCE LINE.

ELSEWHERE...MORE WDLY SCTD STORMS MAY FORM CLOSER TO SFC LOW AND
ALONG ASSOCIATED STNRY FRONT EXTENDING NE FROM LOW DURING THE NEXT
SEVERAL HOURS.  IF STORMS DO INDEED FORM IN THIS REGION...A
CONDITIONAL RISK ALSO WILL EXIST FOR LOW-LVL
MESOS/TORNADOES...ALTHOUGH OVERALL THREAT HERE DOES NOT APPEAR TO BE
AS GREAT AS THAT IN THE SRN AND ERN PORTIONS OF THE WW.

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 500.
MEAN STORM MOTION VECTOR 20025.


...CORFIDI

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