Tornado Watch 603

Issued

Sep 1, 2012, 1:19 PM CDT (18:19 UTC)

Expired

Sep 1, 2012, 9:30 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), 126 km from the middle of the area, began a volume at 18:19 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

20%

Ten or more severe wind reports

40%

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

80%

• Mesoscale Discussion 1849Sep 1, 12:41 PM CDT
• Mesoscale Discussion 1851Sep 1, 3:30 PM CDT
• Mesoscale Discussion 1854Sep 1, 5:43 PM CDT
• Mesoscale Discussion 1857Sep 1, 7:56 PM CDT

678 
WWUS20 KWNS 011824
SEL3
SPC WW 011824
ILZ000-KYZ000-MOZ000-020300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 603
NWS STORM PREDICTION CENTER NORMAN OK
120 PM CDT SAT SEP 1 2012

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

       CENTRAL AND SOUTHERN ILLINOIS
       WESTERN KENTUCKY
       SOUTHEAST MISSOURI

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 120 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 65 STATUTE
MILES EAST AND WEST OF A LINE FROM 55 MILES NORTH NORTHEAST OF
SALEM ILLINOIS TO 35 MILES EAST SOUTHEAST OF POPLAR BLUFF
MISSOURI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).

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 602...

DISCUSSION...WITH CONTINUED SFC HEATING...TSTMS SHOULD INCREASE IN
STRENGTH ALONG EXISTING SQLN NOW EXTENDING FROM E OF ST LOUIS SSW
INTO SE MO. OTHER STORMS MAY FORM AHEAD OF THIS LINE IN
MOIST/CONFLUENT WARM SECTOR OVER SRN IL...AND POSSIBLY IN WAKE OF
SQLN IN SE MO. DEVELOPMENT ALSO MAY BE FURTHERED IN TIME BY APPARENT
VORT MAX MOVING AROUND SRN QUADRANT OF REMNANT CIRCULATION WITH
FORMER HRCN ISAAC /ATTM CENTERED OVER CNTRL MO/.

WARM MID-LVL TEMPS MAY SOMEWHAT MITIGATE STORM STRENGTH AND/OR DELAY
MORE ROBUST DEVELOPMENT. BUT GIVEN CURRENT INTENSITY
TRENDS...AVAILABILITY OF RICH LOW-LVL MOISTURE...AND PRESENCE OF
AMPLE DEEP SPEED/DIRECTIONAL SHEAR FOR BOTH SUPERCELLS AND LOW-LVL
MESOS...SETUP MAY YIELD A COUPLE TORNADOES IN ADDITION TO SMALL BOWS
WITH DMGG WIND THROUGH THIS EVE.

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 21035.


...CORFIDI

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