Tornado Watch 600

Issued

Aug 31, 2012, 1:56 PM CDT (18:56 UTC)

Expired

Aug 31, 2012, 10:00 PM CDT

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

0.5 in

Strongest gust expected

60 kt

The St Louis radar (KLSX), 96 km from the middle of the area, began a volume at 18:57 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

5%

One or more hailstones of 2 inches or more

5%

Six or more combined severe hail and wind reports

50%

• Mesoscale Discussion 1844Aug 31, 1:26 PM CDT
• Mesoscale Discussion 1847Aug 31, 6:01 PM CDT
• Mesoscale Discussion 1848Aug 31, 9:05 PM CDT

376 
WWUS20 KWNS 311902
SEL0
SPC WW 311902
ARZ000-ILZ000-KYZ000-MOZ000-TNZ000-010300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 600
NWS STORM PREDICTION CENTER NORMAN OK
155 PM CDT FRI AUG 31 2012

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

       NORTHEAST ARKANSAS
       SOUTHWEST ILLINOIS
       FAR WESTERN KENTUCKY
       SOUTHEAST AND EAST CENTRAL MISSOURI
       FAR NORTHWEST TENNESSEE

EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 155 PM UNTIL
1000 PM CDT.

TORNADOES...HAIL TO 0.5 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 60 STATUTE
MILES EAST AND WEST OF A LINE FROM 35 MILES NORTH NORTHWEST OF
ALTON ILLINOIS TO 40 MILES EAST SOUTHEAST OF JONESBORO ARKANSAS.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU0).

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...TSTMS EXPECTED TO FORM LATER THIS AFTN IN RESPONSE TO
SFC HEATING ALONG CONFLUENCE BANDS IN ERN QUADRANT OF REMNANT
CIRCULATION OF ISAAC. AREA VWP DATA SHOW SUFFICIENT LOW LVL SHEAR
FOR LOW-LVL MESOS/POSSIBLE TORNADOES GIVEN RICH LOW-LVL MOISTURE/LOW
LCLS. WHILE LOW LVL SHEAR IN WW REGION IS SOMEWHAT WEAKER RELATIVE
TO YESTERDAY IN THE LWR MS VLY...LOW LVL LAPSE RATES ARE SOMEWHAT
STEEPER AND MAY YIELD A SIMILAR SVR THREAT.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 19035.


...CORFIDI

Tornado Watches in Missouri, 2012Tornado Watches in Illinois, 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.