Severe Thunderstorm Watch 621

Issued

Sep 5, 2012, 2:29 PM CDT (19:29 UTC)

Expired

Sep 5, 2012, 10:00 PM CDT

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

The Paducah radar (KPAH), 122 km from the middle of the area, began a volume at 19:32 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

10%

One or more EF2 to EF5 tornadoes

2%

Ten or more severe wind reports

40%

One or more gusts of 65 knots or more

10%

Ten or more severe hail reports

60%

One or more hailstones of 2 inches or more

20%

Six or more combined severe hail and wind reports

90%

• Mesoscale Discussion 1891Sep 5, 1:10 PM CDT
• Mesoscale Discussion 1893Sep 5, 2:13 PM CDT
• Mesoscale Discussion 1897Sep 5, 5:31 PM CDT

048 
WWUS20 KWNS 051932
SEL1
SPC WW 051932
ARZ000-ILZ000-KYZ000-MOZ000-TNZ000-060300-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 621
NWS STORM PREDICTION CENTER NORMAN OK
225 PM CDT WED SEP 5 2012

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

       NORTHEAST ARKANSAS
       SOUTHERN ILLINOIS
       WESTERN KENTUCKY
       SOUTHEAST AND SOUTH CENTRAL MISSOURI
       NORTHWEST TENNESSEE

EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 225 PM UNTIL
1000 PM CDT.

HAIL TO 2 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 105
STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES NORTHEAST OF
CAPE GIRARDEAU MISSOURI TO 20 MILES SOUTHEAST OF WALNUT RIDGE
ARKANSAS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).

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.

OTHER WATCH INFORMATION...CONTINUE...WW 619...WW 620...

DISCUSSION...TSTMS EXPECTED TO INCREASE IN COVERAGE/STRENGTH OVER
THE NEXT SEVERAL HOURS ZONE OF MODEST DEEP WNWLY SHEAR BUT STRONG
SFC-BASED INSTABILITY ALONG THE SRN EDGE OF THE WLYS. LOW-LVL UPLIFT
MAY BE ENHANCED ALONG WNW-ESE OUTFLOW BOUNDARY IN NRN PART OF WW
/LEFT BY IL-IND MCS/. DEEP EML AND RICH LOW-LVL MOISTURE SHOULD
FOSTER DEVELOPMENT OF HAIL/LOCALLY DMGG WIND IN STRONGER
STORMS...WITH THE ACTIVITY POSSIBLY MERGING INTO A SE-MOVING CLUSTER
BY EVE.

AVIATION...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 550. MEAN STORM
MOTION VECTOR 29025.


...CORFIDI

Severe Thunderstorm Watches in Missouri, 2012Severe Thunderstorm Watches in Tennessee, 2012Severe Thunderstorm Watches in Arkansas, 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.