Severe Thunderstorm Warning 175, NWS St. Louis, MO

000 
WWUS53 KLSX 231757
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
1256 PM CDT FRI MAY 23 2008

ILC001-231806-
/O.EXP.KLSX.SV.W.0175.000000T0000Z-080523T1800Z/
ADAMS IL-
1256 PM CDT FRI MAY 23 2008

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN ADAMS COUNTY EXPIRES
AT 100 PM CDT...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED AND NO LONGER 
APPEARED TO BE SEVERE.

LAT...LON 4018 9093 3995 9094 4002 9149 4004 9149
      4006 9151 4010 9151 4020 9151
TIME...MOT...LOC 1756Z 283DEG 22KT 4009 9111

$$

BRITT

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1221 PM CDT FRI MAY 23 2008

.UPDATE...
/1144 AM CDT FRI MAY 23 2008/
FORECAST UPDATED MAINLY TO REDUCE POPS IN THE NRN PART OF THE CWA
NOW THAT THE REMANTS OF THE EARLIER MCS HAVE PUSHED EAST OF THE
AREA. HAVE CONTINUED 30-40 POPS FOR SCT SHRA/TSRA THIS AFTERNOON
AS NAM DEPICTS MUCAPES IN THE 400-1000 J/KG RANGE BY 21Z. LATEST
SURFACE ANALYSIS SHOWS MCS HAS LEFT A OUTFLOW BOUNDARY THAT
EXTENDS FROM NERN MO SEWD INTO S CNTRL IL AND THE WARM FRONT
IS MOVING SLOWLY NWD ACROSS SRN MO...BOTH OF WHICH WILL ACT AS
POTENTIAL FOCUSING MECHANISMS. ONLY MADE MINOR ADJUSTMENTS TO
TEMPERATURE AND CLOUDS.

BRITT

&&

.DISCUSSION...
/425 AM CDT FRI MAY 23 2008/
COMPLEX FORECAST...NOTABLY FOR THE NEXT 18HRS. SEVERAL AREAS OF
PCPN EITHER BREAKING OUT/DEVELOPING ATTM OR ONGOING OVER THE CNTRL
CONUS. OF PARTICULAR INTEREST TO OUR AREA ARE A LARGE BOWING MCS
PUSHING INTO NWRN MO/WRN IA...A SML MCS MOVING INTO FAR SWRN MO...
AND SEVERAL SML TSRA CELLS DEVELOPING NEAR THE MS RVR.

NWRN MO/WRN IA BOWING MCS IS HEADING E PER FORWARD PROP VECTORS...
BUT INTO AIR THAT HAS LESS MUCAPE...AND SLIGHTLY MORE CIN
CALCULATED FROM H850. AS IT MOVES AWAY FROM ITS SOURCE
REGION...IT SHOULD LOSE SOME OF ITS STRUCTURE BUT NEVERTHELESS HAS
A GOOD LIKELIHOOD OF PUSHING THRU THE FAR NRN FA DURING MID-LATE
MRNG.

THE SML MCS MOVING INTO FAR SWRN MO...FORWARD PROP VECTORS HAVE
COMING TO A NEAR STANDSTILL OR HEADING MORE TO THE SE. SHOULD IT
SOMEHOW SURVIVE THE MORNING HOWEVER...IT MAY RECEIVE RENEWED
IMPETUS TO HEAD EWD TOWARDS THE FA. CONSIDER THIS POSSIBILITY
RELATIVELY SMALL...AND SO HAVE ONLY PLACED CHANCE POPS IN FOR THE
AFTN FOR THE SRN HALF OF THE FA.

THE SEVERAL SML TSRA CELLS DEVELOPING NEAR THE MS RIVER ARE PART
OF AN AREA OF H850 MOISTURE CONVERGENCE AND WAA THAT ARE
INTERSECTING AN AREA OF NO CIN. THIS AREA WILL SLOWLY PROPAGATE
NEWD AND RESIDE OVER THE FAR NERN FA FOR MUCH OF THE DAY. WHILE
BEST CHANCES FOR PCPN WILL BE EARLY-MD MORNING...MAY SEE
ADDITIONAL DEVELOPMENT LATER THIS AFTERNOON DEPENDING ON ITS
INTERACTION WITH THE NRN BOWING MCS.

HEADING INTO TONIGHT...ACITIVITY SHOULD ALL QUIET DOWN BY LATE
EVENING. A NEW MCS WILL DEVELOP OVER THE CNTRL PLAINS TONIGHT AND
ATTEMPT TO HEAD EWD...BUT SHOULD DISSIPATE BEFORE REACHING
CNTRL/NERN MO SATURDAY. THE REPRIEVE IN THE ACTIVITY WILL
THEREFORE CONTINUE UNTIL SUNDAY WHEN SLY SFC WINDS WILL ADVECT IN
HIGHER SFC DEWPOINTS...INTO THE MID-UPR 60S. THIS ALONG WITH MDTLY
UNSTABLE AIR AT THE MID LEVELS APPROACHING FROM THE W AND THE
APPROACH OF A FRONTAL ZONE FROM THE NW WILL RESULT IN POPS
RETURNING FOR THE NWRN AND NRN FA. RAIN CHANCES WILL THEN SPREAD
OVER THE ENTIRE FA FOR MEMORIAL DAY.

PREFERRED WARMER MOS TEMPS OVER THE NEXT FEW DAYS...AS AGREE WITH
REASONING IN PREVIOUS FORECAST WITH WARMER AIR OSTENSIBLY PUSHING
ITS WAY HERE OVER TIME. DID TRIM A FEW DEGS OFF FROM PREVIOUS HI
TEMPS FOR TODAY...BUT BY SUNDAY...SWLY SFC WNDS AND 18-20C H850
TEMPS SHOULD DRIVE TEMPS WELL INTO THE 80S OVER MUCH OF THE FA.

TES

&&

.AVIATION...
/1216 PM CDT FRI MAY 23 2008/
FOR THE 18Z TAFS...
DO NOT EXPECT AREAL COVERAGE OF SHRA/TSRA ACROSS THE FORECAST AREA
THIS AFTERNOON TO BE ENOUGH TO WARRANT A TEMPO GROUP AT THIS
TIME...SO HAVE GONE WITH JUST VC OR CB REFERENCES. HAVE ALSO GONE
INITIALLY WITH MVFR CIGS AT KUIN/KSTL/KSUS TO ACCOUNT FOR CURRENT
TRENDS. ALSO EXPECT CIGS TO LOWER LATE TONIGHT INTO TOMORROW
MORNING. OTHERWISE...EXPECT PERSISTENT ELY WIND OUTSIDE OF TSRA
THROUGH THE END OF THE PERIOD.

BRITT

&&

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

WFO LSX

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ST LOUIS MO
437 AM CDT FRI MAY 23 2008

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-241200-
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-LEWIS-
SHELBY-MARION-MONROE-RALLS-PIKE-BOONE-AUDRAIN-MONITEAU-COLE-OSAGE-
CALLAWAY-MONTGOMERY-LINCOLN-GASCONADE-WARREN-ST. CHARLES-FRANKLIN-
ST. LOUIS-ST. LOUIS CITY-JEFFERSON-CRAWFORD-WASHINGTON-
ST. FRANCOIS-STE. GENEVIEVE-IRON-MADISON-REYNOLDS-
437 AM CDT FRI MAY 23 2008

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

THERE IS A CHANCE FOR THUNDERSTORMS AREAWIDE TODAY...AND IN PARTS
OF SOUTHWEST ILLINOIS THIS EVENING. WHILE SOME OF THE STRONGER
STORMS MAY BE CAPABLE OF UP TO DIME SIZE HAIL AND 45 MPH GUSTS...
SEVERE WEATHER IS NOT EXPECTED.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS FOR PARTS OF CENTRAL
AND NORTHEAST MISSOURI ON SATURDAY.

A COLD FRONT WILL APPROACH NORTHEAST MISSOURI AND WEST CENTRAL
ILLINOIS ON SUNDAY...AND RESULT IN A CHANCE FOR THUNDERSTORMS IN
THIS AREA. THE FRONT WILL THEN MOVE SOUTH INTO THE BI-STATE REGION
ON MEMORIAL DAY AND CONTINUE TO DRIFT SLOWLY SOUTH THROUGH
WEDNESDAY. THIS FRONT WILL BRING THE AREA ANOTHER CHANCE FOR
THUNDERSTORMS. THERE IS SOME POTENTIAL FOR SEVERE WEATHER DURING
ON SUNDAY AND MEMORIAL DAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT.

&&

FOR A GRAPHICAL VERSION OF THIS INFORMATION SEE OUR
WEBPAGE AT (LOWERCASE)... HTTP://WWW.WEATHER.GOV/LSX/?N=HWO1

TES