Severe Thunderstorm Warning 520, NWS St. Louis, MO

000 
WWUS53 KLSX 112330
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
629 PM CDT MON SEP 11 2006

ILC001-009-112339-
/O.CAN.KLSX.SV.W.0520.000000T0000Z-060911T2345Z/
BROWN IL-ADAMS IL-
629 PM CDT MON SEP 11 2006

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN ADAMS AND WESTERN
BROWN COUNTIES IS CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED AND NO LONGER 
APPEARED TO BE SEVERE. HOWEVER...SHOWERS AND THUNDERSTORMS WILL 
PERSIST ACROSS THE AREA OVER THE NEXT COUPLE OF HOURS. EXPECT BRIEF 
HEAVY RAINFALL...SMALL HAIL AND GUSTY WINDS TO 40 MPH WITH THE 
STRONGER STORMS.

LAT...LON 4010 9123 3985 9121 3986 9074 4011 9074

$$

BYRD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
545 PM CDT MON SEP 11 2006

.DISCUSSION...
A LOW PRESSURE SYSTEM WAS LOCATED OVER CENTRAL MO EARLY THIS
AFTERNOON WITH A COLD FRONT TRAILING SOUTHWESTWARD INTO EASTERN OK.
LOW WILL MOVE NORTHEASTWARD TONIGHT AND BY 12Z TUESDAY IT IS
FORECAST TO BE LOCATED OVER NORTHERN IN. COLD FRONT IS THEN FORECAST
TO EXTEND ACROSS CENTRAL IL INTO CENTRAL AR. FRONT SHOULD BE CLEAR
OF THE FORECAST AREA BY EVENING.

LATEST LAPS DATA INDICATED CAPES HAVE INCREASED TO ABOUT 2000 J/KG
ACROSS CENTRAL MO WITH LIS OF -4. SATELLITE IMAGERY SHOWED PLENTY
OF CLEAR SKY FROM CENTRAL MO INTO NORTHEAST MO/WEST CENTRAL IL. AREA
APPEARS TO BE PRIME AREA FOR CONVECTION DEVELOPING DURING THE
AFTERNOON.

MODELS ARE FAIRLY SIMILAR IN FORECASTING H5 LOW WHICH WAS OVER THE
UPPER MIDWEST THIS MORNING TO DIG SLOWLY SOUTHWARD INTO THE REGION.
BY TUESDAY EVENING, THE UKMET, NAM, EUROPEAN AND GFS ALL FORECAST
THE LOW TO BE CENTERED OVER SOUTHEAST IA TUESDAY EVENING. UPPER
SYSTEM WILL MOVE INTO THE OH/TN VALLEY BY WEDNESDAY EVENING. DRIER
AIR WILL ADVECT INTO THE AREA ON TUESDAY AHEAD OF UPPER SYSTEM
DROPPING DOWN FROM THE NORTH.

IN THE EXTENDED PERIOD, SURFACE HIGH PRESSURE WILL COVER THE EASTERN
THIRD OF THE COUNTRY WITH SEVERAL LOW PRESURE SYSTEMS OVER THE GREAT
PLAINS AND GREAT BASIN ON FRIDAY. UPPER RIDGE IS FORECAST TO COVER
THE UPPER MIDWEST FRIDAY EVENING WITH CLOSED H5 LOW OVER THE
CASCADES OF THE PACIFIC NORTHWEST. SOUTHERLY FLOW WILL PREVAIL
ACROSS THE REGION OVER THE WEEKEND AHEAD OF A COLD FRONT ACROSS THE
GREAT PLAINS. THE GFS IS FORECASTING MOISTURE TO RETURN INTO THE
REGION ON SUNDAY.

TPS
&&

.AVIATION...
FOR THE 00Z TAFS...
A LOW PRESSURE SYSTEM WAS CENTERED OVER NORTHEAST MO AT THIS TIME. A
COLD FRONT TRAILED ACROSS SOUTHWEST MO INTO EAST CENTRAL OK NEAR A
AIZ-JLN-MKO LINE. WIDESPREAD IFR/MVFR CEILINGS PREVAILED ACROSS
NORTHWEST MO/NORTHEAST KS BEHIND THE FRONT. EXPECT THE LOWER
CEILINGS TO AFFECT MUCH OF THE FORECAST AREA LATER TONIGHT AS THE
COLD FRONT MOVES SLOWLY SOUTHEASTWARD.

SCATTERED THUNDERSTORMS CONTINUED FROM NORTHEAST MO INTO CENTRAL MO
AT THIS TIME. THE STORMS PRODUCED WIND GUSTS OF 35 KTS AT COU WITH
BRIEF HEAVY RAIN AND VISIBILITY OF A QUARTER MILE DURING THE PAST
HOUR. THE SCATTERED THUNDERSTORMS WERE MOVING EASTWARD ABOUT 20 KTS
AND SHOULD AFFECT THE STL METRO AREA EARLY THIS EVENING. THE
THUNDERSTORMS ARE EXPECTED TO BE EAST OF THE UIN AND COU SITES
WITHIN AN HOUR.

TPS

&&

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

WFO LSX

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ST LOUIS MO
309 PM CDT MON SEP 11 2006

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-121200-
ADAMS IL-AUDRAIN-BOND IL-BOONE-BROWN-CALHOUN IL-CALLAWAY-CLINTON IL-
COLE-CRAWFORD-FAYETTE IL-FRANKLIN-GASCONADE-GREENE IL-IRON-JEFFERSON-
JERSEY IL-KNOX-LEWIS-LINCOLN-MACOUPIN IL-MADISON-MADISON IL-MARION-
MARION IL-MONITEAU-MONROE-MONROE IL-MONTGOMERY-MONTGOMERY IL-OSAGE-
PIKE-PIKE IL-RALLS-RANDOLPH IL-REYNOLDS-SHELBY-ST CHARLES-
ST CLAIR IL-ST FRANCOIS-ST LOUIS-ST LOUIS CITY-STE GENEVIEVE-WARREN-
WASHINGTON-WASHINGTON IL-
309 PM CDT MON SEP 11 2006

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

.DAY ONE...TONIGHT

A STORM SYSTEM MOVING THROUGH THE MID MISSISSIPPI RIVER VALLEY
WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE REGION
THROUGH TONIGHT. LOCALLY HEAVY RAINFALL IS POSSIBLE WITH SOME OF
THESE STORMS. IN ADDITION...THERE IS A SLIGHT CHANCE OF SEVERE
THUNDERSTORMS...WHICH MAY PRODUCE UP TO QUARTER SIZE HAIL AND WIND
GUSTS IN EXCESS OF 60 MPH DURING EVENING HOURS...MAINLY ALONG AND
NORTH OF A STEELVILLE MISSOURI TO VANDALIA ILLINOIS LINE.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THROUGH THE EVENING HOURS.

BYRD