URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 643
NWS STORM PREDICTION CENTER NORMAN OK
445 PM CDT THU SEP 2 2010

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

       CENTRAL AND SOUTHERN ILLINOIS
       CENTRAL AND SOUTHERN MISSOURI

EFFECTIVE THIS THURSDAY AFTERNOON FROM 445 PM UNTIL MIDNIGHT CDT.

HAIL TO 1.5 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 70
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 50 MILES NORTHWEST
OF MONETT MISSOURI TO 25 MILES SOUTH OF DANVILLE ILLINOIS.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU3).

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 642...

DISCUSSION...THUNDERSTORMS ARE SLOWLY INCREASING IN COVERAGE AND
INTENSITY ALONG/AHEAD OF A COLD FRONT MOVING SEWD INTO LOWER MO AND
MIDDLE MS VALLEYS.  PRE-FRONTAL AIR MASS IS WARM WITH SURFACE
TEMPERATURES IN THE MID/UPPER 80S...AND DEW POINTS IN THE LOW 70S
ARE CONTRIBUTING TO MLCAPE OF 1500-2500 J/KG.  WINDS ALOFT AND DEEP
LAYER SHEAR IS EXPECTED TO INCREASE /ESPECIALLY OVER CNTRL PART SOF
MO AND IL/ AS UPSTREAM UPPER TROUGH MOVES TOWARD THE MS VALLEY
TONIGHT.  DAMAGING WIND GUSTS AND HAIL WILL BE THE PRIMARY SEVERE
THREATS.

AVIATION...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 550. MEAN STORM
MOTION VECTOR 26025.


...WEISS

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 642
NWS STORM PREDICTION CENTER NORMAN OK
330 PM CDT THU SEP 2 2010

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

       LARGE PART OF SOUTHEAST KANSAS
       LARGE PART OF NORTHERN AND WESTERN OKLAHOMA
       PARTS OF NORTHWEST TEXAS

EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 330 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 80
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES SOUTH
SOUTHWEST OF CHILDRESS TEXAS TO 45 MILES EAST NORTHEAST OF
CHANUTE KANSAS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).

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.

DISCUSSION...STRONG COLD FRONT WILL INITIATE THUNDERSTORMS AS IT
ENCOUNTERS AN INCREASINGLY UNSTABLE AND WEAKLY CAPPED AIR MASS. 
WITH DCAPES TO 1500 J/KG AND MLCAPES AOA 2000 J/KG...DAMAGING WINDS
WILL BECOME INCREASING THREAT AS STORMS DEVELOP ALONG AND FRONT AS
IT CONTINUES SWD THRU THE WATCH.

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 30020.


...HALES

STATUS REPORT ON WW 643

SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 NNW JLN
TO 10 NW ALN TO 35 WSW SPI TO 25 ESE UIN.

..GOSS..09/03/10

ATTN...WFO...LSX...ILX...LOT...SGF...EAX...


STATUS REPORT FOR WS 643 

SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS 

ILC005-017-019-021-023-025-027-029-033-035-039-041-045-049-051-
053-075-079-101-105-107-113-115-117-119-121-125-129-133-135-137-
139-147-157-159-163-167-171-173-179-183-189-030240-

IL 
.    ILLINOIS COUNTIES INCLUDED ARE

BOND                 CASS                CHAMPAIGN           
CHRISTIAN            CLARK               CLAY                
CLINTON              COLES               CRAWFORD            
CUMBERLAND           DE WITT             DOUGLAS             
EDGAR                EFFINGHAM           FAYETTE             
FORD                 IROQUOIS            JASPER              
LAWRENCE             LIVINGSTON          LOGAN               
MCLEAN               MACON               MACOUPIN            
MADISON              MARION              MASON               
MENARD               MONROE              MONTGOMERY          
MORGAN               MOULTRIE            PIATT               
RANDOLPH             RICHLAND            ST. CLAIR           
SANGAMON             SCOTT               SHELBY              
TAZEWELL             VERMILION           WASHINGTON          


MOC009-011-029-039-043-055-057-059-065-067-071-073-077-085-093-
097-099-105-109-119-123-125-131-145-151-153-161-167-169-179-183-

STATUS REPORT ON WW 642

SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 55 SSW CDS
TO 15 ESE LTS TO 25 ESE CHK.

..STOPPKOTTE..09/03/10

ATTN...WFO...ICT...TOP...SGF...EAX...OUN...TSA...LUB...AMA...


STATUS REPORT FOR WS 642 

SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS 

ARC007-015-087-143-030240-

AR 
.    ARKANSAS COUNTIES INCLUDED ARE

BENTON               CARROLL             MADISON             
WASHINGTON           


OKC001-019-021-031-033-041-049-063-067-099-101-107-111-123-133-
137-141-145-030240-

OK 
.    OKLAHOMA COUNTIES INCLUDED ARE

ADAIR                CARTER              CHEROKEE            
COMANCHE             COTTON              DELAWARE            
GARVIN               HUGHES              JEFFERSON           
MURRAY               MUSKOGEE            OKFUSKEE            
OKMULGEE             PONTOTOC            SEMINOLE            
STEPHENS             TILLMAN             WAGONER             


TXC009-023-077-155-269-275-485-487-030240-

MESOSCALE DISCUSSION 1788
NWS STORM PREDICTION CENTER NORMAN OK
0918 PM CDT THU SEP 02 2010

AREAS AFFECTED...WRN N TX...SWRN OK INTO E CNTRL OK

CONCERNING...SEVERE THUNDERSTORM WATCH 642...

VALID 030218Z - 030345Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 642
CONTINUES.

SEVERE THREAT WILL CONTINUE TO DIMINISH AS STORMS TRACK SEWD THIS
EVENING. A NEW WW IS NOT ANTICIPATED.

SFC OBSERVATIONS THE LAST HOUR HAVE LARGELY SHOWED A DECREASE IN
WIND GUSTS FROM WRN N TX INTO SWRN OK TO E CNTRL OK...ALTHOUGH
STORMS COULD STILL REMAIN SEVERE FOR ANOTHER HOUR OR SO. AS STORMS
CONTINUE TO TRACK SEWD...AIR MASS WILL BECOME LESS UNSTABLE AND
STORMS WILL BECOME MORE ELEVATED...EFFECTIVELY ENDING DAMAGING WIND
THREAT. HEAVY RAINFALL AND GUSTY WINDS WITH SMALL HAIL WILL STILL BE
POSSIBLE BUT SEVERE THREAT SHOULD LARGELY BE OVER BY THE WATCH
EXPIRATION TIME.

..STOPPKOTTE.. 09/03/2010

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...SGF...TSA...FWD...OUN...SJT...LUB...AMA...

LAT...LON   34710037 34220086 33610098 33120067 32960035 33079930
            33819731 35279508 35719445 36279430 36539454 36679510
            34710037 

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0756 PM CDT THU SEP 02 2010

VALID 030100Z - 031200Z

...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS SRN PLAINS TO UPPER
GREAT LAKES...

...SYNOPSIS...
PROGRESSIVE NRN-STREAM PATTERN WILL REMAIN DOMINATED BY RIDGING
ALOFT OVER PAC NW...SHIFTING EWD TOWARD NRN ROCKIES...AND STG
SHORTWAVE TROUGH NOW EVIDENT IN MOISTURE CHANNEL IMAGERY FROM MN
ACROSS NWRN IA TO S-CENTRAL NEB.  THIS TROUGH IS FCST TO MOVE EWD
AND DEEPEN...DEVELOPING CLOSED 500 MB CIRCULATION OVER LS BY
12Z...WHILE SRN PORTION REACHES MID MS VALLEY.  ASSOCIATED/STG SFC
COLD FRONT WAS ANALYZED AT 23Z FROM SFC LOW NEAR GRB...SWWD ACROSS
NWRN/EXTREME W-CENTRAL IL...SWRN MO...CENTRAL OK...TX SOUTH-PLAINS
REGION NEAR LBB...TO SERN NM.  FRONT IS EXPECTED TO SURGE SWD ACROSS
SRN HIGH PLAINS AND SEWD OVER OK/MO/IL.  BY END OF PERIOD...FRONT
SHOULD EXTEND FROM NWRN OH SWWD ACROSS PORTIONS WRN/CENTRAL
KY...EXTREME WRN TN...SRN AR...CENTRAL TX...NRN CHIHUAHUA.

...SRN PLAINS TO UPPER GREAT LAKES...
SCATTERED TSTMS -- MOSTLY IN LINES AND MULTICELLULAR SEGMENTS...WITH
SOME DISCRETE CELLS -- CONTINUE ON BOTH SIDES OF COLD FRONT BETWEEN
WI/IL AND TX HIGH PLAINS.  SVR GUSTS HAVE BEEN MEASURED AT A FEW OBS
SITES AND MESONET STATIONS MAINLY IN SRN PORTIONS OUTLOOK AREA.  REF
SPC WWS 642-643 AND ATTENDANT MESOSCALE DISCUSSIONS FOR DETAILS ON
NEAR-TERM SVR POTENTIAL.

GREATEST REMAINING THREAT FOR DAMAGING GUSTS AND ISOLATED HAIL WILL
BE WITH ACTIVITY ALONG/AHEAD OF SFC COLD FRONT.  ALTHOUGH MAIN
THREAT IS DAMAGING WIND...SVR HAIL POTENTIAL STILL MAY EXIST WITH
RELATIVELY DISCRETE TSTMS...ESPECIALLY FROM OZARKS NEWD WHERE
VERTICAL SHEAR WILL SUPPORT MORE ORGANIZED UPDRAFTS.  ACTIVITY OVER
SRN PLAINS INTO OZARKS WILL BE AIDED BY DEEP/WELL-MIXED BOUNDARY
LAYERS FOR ANOTHER COUPLE OF HOURS...BEFORE DIABATIC COOLING BEGINS
TO STABILIZE BOUNDARY LAYER.  FARTHER NE...STRONGER DEEP-LAYER SHEAR
IS EVIDENT...BUT WITH WEAKER LAPSE RATES ALOFT AND IN BOUNDARY
LAYER.  IN BOTH CASES MAIN THREAT IS DAMAGING WIND...WITH SOMEWHAT
LONGER-LIVED THREAT OVER SRN PLAINS GIVEN DRIER AND MORE UNSTABLE
BOUNDARY LAYER INTO WHICH ORGANIZED OUTFLOW REGIME WILL BE MOVING.
SVR THREAT SHOULD DIMINISH APPRECIABLY AFTER ABOUT 05Z THROUGHOUT
OUTLOOK AREA.

..EDWARDS.. 09/03/2010