River Flood Warning 105, NWS St. Louis, MO

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
612 AM CDT SAT MAY 9 2009

.DISCUSSION...
/442 AM CDT SAT MAY 9 2009/

MODELS CONTINUE TO TAKE THE ZONAL FLOW AT MID LEVELS THRU THE END
OF THE WEEKEND BEFORE BUILDING A WEAK H500 RIDGE INTO THE CNTRL
CONUS HEADING INTO EARLY NEXT WEEK. A PAIR OF SHORTWAVES WILL MOVE
NEAR OUR REGION OVER THE NEXT COUPLE OF DAYS...WITH THE FIRST
LARGELY MISSING US TO THE N TODAY AND TONIGHT...AND THE SECOND
DELIVERING A MORE DIRECT HIT ON SUNDAY AND SUNDAY NIGHT. AT THE
SFC...HI PRES BUILDS IN TODAY AND REMAINS THRU SUNDAY AFTN WHEN A
CDFNT WILL EDGE THE AREA TO THE E SUNDAY NIGHT INTO MONDAY.
RIDGING WILL RETURN TO THE AREA BY MONDAY NIGHT BEFORE SLY RETURN
FLOW INITATES ON TUESDAY.

THIS PATTERN WILL KEEP OUR REGION AOB NORMAL FOR TEMPS THRU MONDAY
UNTIL THE SLY FLOW WILL BRING A RETURN OF THE WARM AIR.

THE COOL TEMPS WILL ALSO SIGNAL A LARGELY STABLE AIRMASS IN PLACE
OVER THE AREA WITH THE CLOSEST BAROCLINIC ZONE TO REMAIN ALONG THE
MO/AR BORDER AND SRN KY AND THIS WILL BE WHERE THE MAIN THUNDER
CHCS WILL LINGER THE NEXT COUPLE OF DAYS. FURTHER N INTO OUR
REGION...LOOK FOR A PERIOD OR TWO OF DRY WX TO TAKE HOLD ALTHOUGH
IT WILL BE INTERRUPTED BRIEFLY BY THE CHANCE FOR SHRA SUNDAY
AFTERNOON AND EVENING AS A SHORTWAVE MOVES THRU WITH REASONABLY
STRONG LIFT...BUT IT WILL BE GENERALLY TOP HEAVY...AND SO EXPECT
THE SHRA TO BE SPOTTY.

THE MORE ACTIVE SENSIBLE WX MAKES A RETURN TUESDAY NIGHT RIGHT
BEHIND THE RETURN OF THE WARMER AIR ON TUESDAY WITH THE POTENTIAL
FOR STRONG STORMS DURING MID WEEK.

TES

&&

.AVIATION...
/524 AM CDT SAT MAY 9 2009/
FOR THE 12Z TAFS...A CDFNT HAS MOVED WELL SE OF THE TAF SITES ATTM
WITH NWLY WNDS INTENSIFYING BHND IT IN UIN AND COU. THE NWLY SFC
WNDS SHOULD PICK UP IN SPEED AT STL/SUS AND BCM GUSTY BY 13Z OR
14Z THIS MRNG. THESE NWLY WNDS WILL DIMINISH LT THIS AFTN AND BCM LGT
THIS EVNG AS THE SFC RDG OVER THE PLAINS BLDS SEWD INTO THE CWA
AND THE SFC LOW OVER THE GRT LKS REGION MOVES FURTHER NE OF THE
AREA. MID LVL CLOUDS WILL MOVE THRU COU...STL AND SUS THIS MRNG
BUT THESE SHOULD ADVCT S OF THE TAF SITES BY THIS AFTN. A BAND OF
LOW LVL CLOUDS OVER IA MAY DROP INTO UIN EARLY THIS MRNG...ALTHOUGH
SOME OF THIS CLOUD CVR HAS BEEN DISSIPATING AS IT MOVES SEWD INTO
NRN MO. MAY JUST INCLUDE A SCT CLOUD GRP ARND 2000-3000 FT IN UIN
THIS MRNG. MAY ALSO HAVE SCT DIURNAL CUMULUS CLOUDS DVLPG OVER THE
CWA LT THIS MRNG. THESE LOW LVL CLOUDS SHOULD DISSIPATE BY SUNSET
THIS EVNG...WITH LTL CLOUD CVR EXPECTED TGT. MID-HI LVL CLOUDS MAY
ADVCT EWD INTO THE CWA SUN MRNG AHD OF AN APPROACHING SHRTWV TROF.

GKS

&&

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

WFO LSX

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ST LOUIS MO
400 AM CDT SAT MAY 9 2009

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-101200-
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-
400 AM CDT SAT MAY 9 2009

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

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

MODERATE TO MAJOR FLOODING CONTINUES ALONG VARIOUS RIVERS...MOST
NOTABLY ON THE ILLINOIS RIVER AND AT CHESTER ON THE MISSISSIPPI
RIVER. PLEASE SEE THE APPROPRIATE FLOOD PRODUCTS FOR FURTHER
INFORMATION.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THERE IS A CHANCE FOR THUNDERSTORMS TUESDAY NIGHT THROUGH
THURSDAY NIGHT ACROSS MUCH OF THE AREA.

MODERATE TO MAJOR FLOODING CONTINUES ALONG VARIOUS RIVERS...MOST
NOTABLY ON THE ILLINOIS RIVER AND AT CHESTER ON THE MISSISSIPPI
RIVER. PLEASE SEE THE APPROPRIATE FLOOD PRODUCTS FOR FURTHER
INFORMATION.

.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