Severe Thunderstorm Warning 275, NWS St. Louis, MO

858 
WWUS53 KLSX 072041
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
341 PM CDT FRI SEP 7 2012

MOC055-221-072100-
/O.CON.KLSX.SV.W.0275.000000T0000Z-120907T2100Z/
CRAWFORD MO-WASHINGTON MO-
341 PM CDT FRI SEP 7 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR WEST CENTRAL
WASHINGTON AND EAST CENTRAL CRAWFORD COUNTIES UNTIL 400 PM CDT...

AT 339 PM CDT...A SEVERE THUNDERSTORM WAS LOCATED 10 MILES NORTHEAST
OF CHERRYVILLE...AND MOVING EAST AT 15 MPH.

HAZARD...QUARTER SIZE HAIL AND 60 MPH WIND GUSTS.

SOURCE...RADAR INDICATED.

IMPACT...MINOR DAMAGE TO VEHICLES...ROOFS AND WINDOWS. MINOR TREE
         DAMAGE...WITH LIMBS UP TO ONE INCH IN DIAMETER BROKEN.

LOCATIONS IMPACTED INCLUDE...
  MAINLY RURAL AREAS OF EXTREME EASTERN CRAWFORD AND WESTERN
  WASHINGTON COUNTIES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
BUILDING.

&&

LAT...LON 3796 9110 3804 9094 3784 9092 3788 9124
      3791 9124
TIME...MOT...LOC 2041Z 275DEG 13KT 3791 9112

HAIL...1.00IN
WIND...60 MPH

$$

TES

793 
WWUS53 KLSX 072103
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
403 PM CDT FRI SEP 7 2012

MOC055-221-072111-
/O.EXP.KLSX.SV.W.0275.000000T0000Z-120907T2100Z/
CRAWFORD MO-WASHINGTON MO-
403 PM CDT FRI SEP 7 2012

...THE SEVERE THUNDERSTORM WARNING FOR WEST CENTRAL WASHINGTON 
COUNTY IS BEING REISSUED...
...SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL CRAWFORD COUNTY HAS 
EXPIRED...

THE SEVERE THUNDERSTORM THREAT HAS EXITED EAST CENTRAL CRAWFORD 
COUNTY...BUT REMAINS IN WEST CENTRAL WASHINGTON COUNTY WHERE THE 
WARNING HAS BEEN REISSUED. PLEASE REFER TO THAT BULLETIN FOR THE 
LATEST SEVERE WEATHER INFORMATION.

ADDITIONAL STRONG THUNDERSTORMS ARE STILL POSSIBLE...AND A SEVERE 
THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 10 PM CDT.

TO REPORT SEVERE WEATHER...CONTACT YOUR NEAREST LAW ENFORCEMENT
AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE
IN ST LOUIS.

LAT...LON 3796 9110 3804 9094 3784 9092 3788 9124
      3791 9124
TIME...MOT...LOC 2041Z 275DEG 13KT 3791 9112

$$

TES

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1232 PM CDT FRI SEP 7 2012

.UPDATE...
ISSUED AT 1047 AM CDT FRI SEP 7 2012

HAVE MADE A QUICK UPDATE TO BASICALLY DELAY THE ONSET OF
CONVECTION ASSOCIATED WITH THE FRONT. AN OUTFLOW BOUNDARY FROM THE
MCS OVER NORTHERN IL HAS MOVED SOUTH THROUGH THE MORNING AND
WITHIN THE LAST HOUR HAS PASSED THRU STL METRO. KLSX VWP INDICATES
THE BOUNDARY IS ROUGHLY 1000 FT DEEP. NOT SURE HOW MUCH FURTHER
SOUTH IT WILL PUSH...BUT DONT BELIEVE IT WILL BE MUCH AS PRESSURE
RISES BEHIND IT ARE WEAK AND DEPTH ISNT OVERWHELMING. BELIEVE
CONVECTION FOR THE MOST PART SHOULD BE SPOTTY THRU EARLY
AFTERNOON. CURRENT THOUGHTS ARE THAT THE AIR MASS WILL RECOVER
THROUGH EASTERN MO AND CAPES WILL BOOST TO 3000+ J/KG BY MID
AFTERNOON. EXPECTING THUNDERSTORMS TO DEVELOP ALONG THE FRONT
BETWEEN UIN-STL AROUND 20-21Z AS LARGE SCALE ASCENT ASSOCIATED
WITH THE UPSTREAM TROF OVERSPREADS THE AREA AND CONVERGENCE ALONG
THE FRONT STRENGTHENS. DEEP LAYER SHEAR WILL BE INCREASING TO
SUPPORT A SEVERE THREAT PER SPC SEVERE OUTLOOK.

GLASS

&&

.SHORT TERM...
ISSUED AT 406 AM CDT FRI SEP 7 2012
(TODAY)

FRONT EXTENDING FROM WI SW TO A SFC LOW OVER SWRN IA AND SW TO A SFC
LOW OVER SERN CO WILL STRENGTHEN AND DROP SEWD THROUGH OUR FORECAST
TODAY AS A STRONG COLD FRONT AS A POSITIVELY TILTED UPPER LEVEL
TROUGH INTENSIFIES OR DEEPENS AND MOVES SEWD THROUGH THE NRN PLAINS
AND GREAT LAKES REGION.  CONVECTION SHOULD DEVELOP ALONG AND JUST
BEHIND THIS FRONT AND AHEAD OF THE UPPER LEVEL TROUGH AS UPPER LEVEL
DIVERGENCE INCREASES OVER OUR AREA AHEAD OF THE UPPER LEVEL TROUGH
AND UPPER LEVEL JET STREAK.  THERE IS A SLIGHT RISK OF SEVERE
STORMS THIS AFTN ACROSS THE SERN HALF OF OUR FORECAST AREA MAINLY
FROM THE ST LOUIS METRO AREA S AND E AS THE ATMOSPHERE GETS QUITE
UNSTABLE AHEAD OF THE COLD FRONT.  THE LOW-MID LEVEL SHEAR WILL ALSO
BE INCREASING AS A MID LEVEL JET STREAK SHIFTS SEWD TO NRN PORTIONS
OF MO AND IL THIS AFTN.  HIGH TEMPERATURES WILL BE COOLER TODAY THAN
YESTERDAY DUE TO THE CLOUD COVER AND PRECIPITATION AND ALSO LOW
LEVEL CAA THIS AFTN ACROSS NERN AND CNTRL MO AS WELL AS WEST CNTRL
IL BEHIND THE COLD FRONT AND 850 MB TROUGH.

GKS

&&

.LONG TERM...
ISSUED AT 229 AM CDT FRI SEP 7 2012
(FRIDAY NIGHT THROUGH THURSDAY)

THE 00Z NAM/GFS/ECMWF ARE CONSISTENT SHOWING THAT THE COLD FRONT
WILL BE EXITING THE SOUTHEAST CWA BY EVENING AND WILL BE WELL
SOUTHEAST OF THE CWA BY MIDNIGHT. STILL...THEY ALSO SHOW THAT THE
500MB TROUGH AXIS WILL JUST BE ENTERING NORTHWEST MISSOURI AT
00Z...SO STRONG POST-FRONTAL ASCENT SHOULD BE GOING ON WELL INTO
THE EVENING. WILL KEEP HIGH CHANCES FOR POPS GOING THROUGH EARLY
EVENING AND THEN DECREASE THEM LATE EVENING AND OVERNIGHT SO THAT
ONLY SCATTERED SHOWERS CAN BE EXPECTED AFTER MIDNIGHT IN THE
SOUTHEASTERN HALF OF THE CWA. THEREAFTER DRY CONDITIONS ARE
EXPECTED THROUGH THE WEEKEND. THESE MODELS ALSO SHOW A WEAK
SHORTWAVE MOVING THROUGH THE GREAT LAKES ON SATURDAY NIGHT THAT
WILL BRING AN ACCOMPANYING COLD FRONT ACROSS THE CWA EARLY SUNDAY.
THIS WILL BE A DRY PASSAGE AS THERE IS VERY LITTLE MOISTURE FOR IT
TO WORK WITH AND ANY ASCENT WILL STAY WELL NORTHEAST OF THE AREA.

TEMPERATURES BEHIND THE FIRST COLD FRONT WILL BE BELOW NORMAL FOR
THE WEEKEND.  MOS TEMPERATURES ARE IN GENERALLY GOOD AGREEMENT.
HIGHS ON SATURDAY ARE SUPPORTED BY MIXING DOWN 850MB TEMPERATURES.
WENT CLOSER TO THE WARMER NAM MOS VALUES ON SUNDAY WHICH ARE ALSO
SUPPORTED BY MIXING.

MEDIUM RANGE MODELS ARE IN RELATIVELY GOOD AGREEMENT THAT UPPER
RIDGE AXIS WILL MOVE ACROSS MISSOURI AND ILLINOIS MONDAY INTO
TUESDAY.  A COLD FRONT WILL THEN ENTER THE MIDWEST AND BECOME
ELONGATED AS IT BEGINS TO ALIGN ITSELF WITH THE ZONAL FLOW ALOFT.
THE GFS KEEPS THE FRONT JUST NORTH OF THE CWA COMPARED TO THE ECMWF
WHICH IS A BIT FARTHER SOUTH. BOTH MODELS ARE NOT SHOWING ANY
QPF...SO WITH KEEP THE MENTION OF RAIN OUT OF THE FORECAST FOR
NOW. TEMPERATURES WILL CLIMB BACK UP TO NEAR NORMAL BY MIDWEEK AS
850MB TEMPS WARM UP INTO THE MID TEENS.

BRITT

&&

.AVIATION...
ISSUED AT 1221 PM CDT FRI SEP 7 2012

POTENT COLD FRONT STRETCHED FROM FAR CORNER OF SE IOWA TO JUST
SOUTH OF A KIRKSVILLE TO KANSAS CITY LINE. THE AIR MASS AHEAD OF
THE FRONT CONTINUES TO DESTABILIZE AND CURRENT THOUGHTS ARE THAT A
LINE OF THUNDERSTORMS WILL DEVELOP ALONG THE FRONT AFTER 20Z WHEN
ITS LOCATION WILL BE SOUTH OF KUIN AND NORTH OF KCOU-KSTL. HAVE
TEMPO GROUPS TO ACCOUNT FOR THE THUNDERSTORM THREAT. GUSTY
NORTHWEST WINDS EXPECTED WITH INITIAL COLD FROPA AND MVFR CIGS
WITH SOME LIGHT RAIN/SHOWERS IN THE WAKE OF THE FRONT. CLEARING
EXPECTED FROM NORTH-SOUTH TONIGHT WITH WINDS DIMINISHING TO 10-13
KTS.

SPECIFICS FOR KSTL...

EXPECTING A LINE OF THUNDERSTORMS TO DEVELOP ALONG AN ENCROACHING
COLD FRONT IMPACTING THE TERMINAL IN THE 20-23Z TIME FRAME. THE
TEMPO GROUP ACCOUNTS FOR THIS BUT CONDITIONS COULD BE WORSE WITH
THE THUNDER...ESPECIALLY STRONG WINDS. LOOKING FOR FROPA AROUND
23Z WITH GUSTY NORTHWEST WINDS AND MVFR CIGS WITH LIGHT
RAIN/SHOWERS IN THE WAKE OF THE FRONT. CLEARING OVERNIGHT WITH
WINDS DIMINISHING TO 10-13 KTS.

GLASS

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

WFO LSX

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ST LOUIS MO
401 AM CDT FRI SEP 7 2012

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-080915-
GREENE IL-MACOUPIN IL-MONTGOMERY IL-BOND IL-FAYETTE IL-CLINTON IL-
MARION IL-WASHINGTON IL-RANDOLPH IL-ADAMS IL-BROWN IL-PIKE IL-
CALHOUN IL-JERSEY IL-MADISON IL-ST. CLAIR IL-MONROE IL-KNOX MO-
LEWIS MO-SHELBY MO-MARION MO-MONROE MO-RALLS MO-PIKE MO-BOONE MO-
AUDRAIN MO-MONITEAU MO-COLE MO-OSAGE MO-CALLAWAY MO-MONTGOMERY MO-
LINCOLN MO-GASCONADE MO-WARREN MO-ST. CHARLES MO-FRANKLIN MO-
ST. LOUIS MO-ST. LOUIS CITY MO-JEFFERSON MO-CRAWFORD MO-
WASHINGTON MO-ST. FRANCOIS MO-STE. GENEVIEVE MO-IRON MO-
MADISON MO-REYNOLDS MO-
401 AM CDT FRI SEP 7 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN AND
CENTRAL MISSOURI AS WELL AS WEST CENTRAL AND SOUTHWEST ILLINOIS.

.DAY ONE...TODAY AND TONIGHT

SEVERE THUNDERSTORMS ARE POSSIBLE THROUGH EARLY THIS EVENING...
MAINLY ALONG AND EAST OF A SPRINGFIELD ILLINOIS TO COLUMBIA
MISSOURI LINE. THE STRONGEST STORMS WILL BE CAPABLE OF PRODUCING
LARGE HAIL...DAMAGING WIND GUSTS IN EXCESS OF 60 MPH...ISOLATED
TORNADOES AND VERY HEAVY DOWNPOURS

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS POSSIBLE THROUGH EARLY THIS EVENING.

BRITT