Severe Thunderstorm Warning 50, NWS Lincoln, IL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
215 PM CDT TUE MAY 6 2003

BIGGEST CHALLENGE OVER NEXT FEW DAYS WILL BE POTENTIAL FOR HEAVY
RAINFALL.

PER SWOMCD...SEVERE THREAT HAS ENDED OVER SOUTHEASTERN COUNTIES AND
HAVE CANCELED SEVERE WATCH 268 FOR THESE COUNTIES A FEW HOURS EARLY.

LATEST OBSERVATIONS SUGGEST THAT NEARLY STATIONARY BOUNDARY REMAINS
JUST SOUTH OF FORECAST AREA THIS AFTERNOON. SEVERAL STRONG TO SEVERE
STORMS FIRED ALONG BOUNDARY LATE THIS MORNING BUT FORCING HAS NOW
SHIFTED EAST AND THREAT HAS DIMINISHED FOR THE TIME BEING.

12Z MODELS IN GOOD AGREEMENT IN MOVING MCS JUST NORTH OF BOUNDARY
OVERNIGHT. HPC...AVN...AND ETA ALL BRING WELL OVER ONE INCH ACROSS
AREA. EXCESSIVE RAINFALL PRODUCT FROM HPC ALSO SUGGEST POTENTIAL FOR
FLOODING.  PRECIP WATER VALUES APPROACHING 2 INCHES CLEARLY
ADVECTING ACROSS BOUNDARY WITH ENHANCED LOW-LEVEL JET. WITH SOME
STREAMS AND RIVERS IN FLOOD OR NEAR BANKFULL WILL PLAN ON ISSUING A
FLOOD WATCH FOR TONIGHT ACROSS ALL BUT THE NORTHWEST PORTION OF
FORECAST AREA.

STRENGTH OF TONIGHTS SYSTEM SHOULD BE ENOUGH TO PUSH BOUNDARY INTO
TENNESSEE VALLEY. THIS SHOULD KEEP BULK OF PRECIP OUT OF AREA UNTIL
BOUNDARY BEGINS TO MOVE NORTHWARD AS WARM FRONT LATE WEDNESDAY
NIGHT. WILL ADJUST POPS FOR WEDNESDAY NIGHT DOWNWARD AS BEST FORCING
SHOULD REMAIN SOUTH OF FORECAST AREA.

AS UPPER LOW GETS CLOSER...BOUNDARY SHOULD BE ABLE TO PULL NORTHWARD
AND PRECIP WITH EACH SUCCESSIVE WAVE WILL LIKELY OCCUR A BIT FURTHER
NORTH. I AM NOT CONFIDENT THAT NORTHWARD MOVEMENT WILL BE AS QUICK
AS PROGGED GIVEN RAIN COOLED AIR ENTRENCHED OVER AIR FROM PREVIOUS
WAVE. GOING WITH A SLIGHTLY FARTHER SOUTH TRACK...MCS SHOULD
CONTINUE TO IMPACT VARIOUS PORTIONS OF THE AREA THURSDAY NIGHT AND
AGAIN ON FRIDAY NIGHT...WITH THE COLD FRONT ASSOCIATED WITH THE MAIN
SURFACE LOW MOVING THROUGH ON SATURDAY NIGHT.

12Z GFS APPEARS FASTER THAN 00Z RUN IN PULLING MAIN LOW OUT OF
AREA.  WILL SPEED CLEARING A BIT COMPARED TO PREVIOUS FORECAST AND
ONLY GO WITH SCT POPS FOR SUNDAY WITH DRY CONDITIONS SUNDAY NIGHT
THROUGH MONDAY NIGHT.  SOME RETURN MOISTURE APPEARS TO BE EVIDENT BY
DAY 7.

WENT SLIGHTLY BELOW GUIDANCE TEMPS THROUGH SATURDAY NIGHT GIVEN
PRECIP EXPECTED AND HIGH BOUNDARY LAYER MOISTURE.

.ILX...FLOOD WATCH FOR TONIGHT SOUTH OF A SCHUYLER COUNTY /
VERMILION COUNTY LINE (ILZ040..042>057...061>063...066>068...071>073)

BARKER

ILZ027>031-036>038-040>057-061>063-066>068-071>073-071100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LINCOLN IL
1142 AM CDT TUE MAY 6 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL AND
SOUTHEAST ILLINOIS.

.DAY ONE...TODAY AND TONIGHT

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF CENTRAL
AND SOUTHEAST ILLINOIS THIS AFTERNOON AND TONIGHT...MAINLY ALONG AND
SOUTH OF A QUINCY TO TERRE HAUTE LINE.  A FRONTAL BOUNDARY EXTENDING
FROM SOUTHERN MISSOURI INTO SOUTHERN ILLINOIS IS EXPECTED TO LIFT
SLOWLY NORTHWARD...TRIGGERING SCATTERED THUNDERSTORMS ACROSS
SOUTHEAST ILLINOIS THIS AFTERNOON.  MEANWHILE...LOW
PRESSURE IN THE SOUTHERN PLAINS WILL MOVE EASTWARD ALONG THE
FRONT...WITH THUNDERSTORMS DEVELOPING AND SPREADING EASTWARD INTO
THE MID MISSISSIPPI RIVER VALLEY BY MID-EVENING...CONTINUING
OVERNIGHT.  SOME OF THESE STORMS COULD BE SEVERE...WITH THE GREATEST
SEVERE WEATHER THREAT IN THE FORM OF LARGE HAIL AND DAMAGING WINDS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A STATIONARY FRONTAL BOUNDARY WILL CONTINUE TO BE THE FOCAL POINT OF
PERIODIC THUNDERSTORM DEVELOPMENT ACROSS CENTRAL AND SOUTHEAST
ILLINOIS THURSDAY THROUGH THE WEEKEND...AS WAVES OF LOW PRESSURE
PROPOGATE ALONG IT.  HEAVY RAINFALL CAN BE EXPECTED DURING THIS
EXTENDED PATTERN OF UNSETTLED WEATHER.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS MAY BE NEEDED THIS AFTERNOON AND TONIGHT...ESPECIALLY IN
LOCATIONS ALONG AND SOUTH OF A QUINCY TO TERRE HAUTE LINE.

&&
THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND CLIMATE
INFORMATION...IS AVAILABLE ON THE INTERNET AT:

HTTP://WWW.CRH.NOAA.GOV/ILX

PLEASE NOTE THAT THE WEB ADDRESS SHOULD BE ALL IN LOWER CASE.

BARNES