Severe Thunderstorm Warning 20, NWS Lincoln, IL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1040 AM CDT TUE MAY 18 2004

.DISCUSSION...LULL CONTINUES AHEAD OF SHORTWAVE TRANSVERSING
MISSOURI ATTM. ONLY ISOLATED PRECIPITATION OCCURRING OVER CENTRAL IL
AND HAVE ADJUSTED ZONES ACCORDINGLY. OCCASIONAL BREAKS IN CLOUD
COVER HAVE ALLOWED TEMPS TO CLIMB HIGHER THAN GOING PACKAGE AND HAVE
MADE ADJUSTMENTS TO HIGHS FOR THIS AFTERNOON IN BOTH GRIDS AND ZFP.

AS SHORTWAVE AND MCV OVER MISSOURI TRACKS EAST THIS AFTERNOON EXPECT
ASSOCIATED CONVECTION TO BECOME SURFACE BASED AND TO TAP INSTABILITY
IN PLACE. STORMS SHOULD BECOME WIDESPREAD AND INCREASE IN INTENSITY.
GOING FORECAST OF LIKELY PRECIPITATION LOOKS REASONABLE BY MIDDLE TO
LATE AFTERNOON.

&&

.PREV DISCUSSION...A LOT TO DEAL WITH TODAY. MAIN FORECAST PROBLEMS
IN THE SHORT TERM ARE CHANCES OF PCPN...HOW MUCH RAINFALL AND WILL
THERE BE ANY SEVERE WEATHER. 00Z GFS AND ETA IN GOOD AGREEMENT ONCE
AGAIN...SO WILL GO WITH A BLEND OF THE TWO.

SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT...
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH AN MCS OVER NORTHERN
ILLINOIS HAS MOVED INTO OUR FAR NORTHERN COUNTIES AS OF 06Z...BUT
LITTLE IN THE WAY OF RAIN. MAIN CONCERN IS THAT THE MCS HAS LAID OUT
A NICE OUTFLOW BOUNDARY THAT CAN BE SEEN ON 88D EXTENDING FROM
PONTIAC TO RUSHVILLE. THIS WILL BE THE FOCUS OF ANY INITIAL ACTIVITY
UNTIL THE FRONTAL BOUNDARY MOVES IN BY MIDDAY. SPC HAS PUT ALL OF
CWA IN A SLIGHT RISK FOR TODAY AND TONIGHT...AS LI/S ARE BETWEEN
MINUS 2 AND MINUS 4 AND CAPES OVER 1500 WILL PERSIST TODAY. SO
ISOLATED SEVERE THUNDERSTORMS NOT OUT OF THE QUESTION. EVEN THOUGH
HPC HAS PUT OUR CWA IN AN ISOLATED RISK FOR EXCESSIVE RAINFALL
THROUGH TONIGHT...QPF AMOUNTS WILL BE CONVECTIVE IN NATURE...SO FEEL
THAT A FLOOD WATCH IN NOT NEEDED FOR TODAY.

HOWEVER...FOR TONIGHT THAT IS A DIFFERENT STORY. FRONTAL BOUNDARY
WILL BE STATIONARY OVER THE CWA WITH MCS DEVELOPMENT A GOOD
POSSIBILITY OVER MO THEN TRACK EASTWARD INTO C IL. FEEL THAT AVN QPF
IS A LITTLE EXCESSIVE WITH CONVECTIVE FEEDBACK PROBLEMS...BUT IT IS
ON THE MARK FOR LOCATION OF HEAVY RAINS AS PWS WILL BE IN EXCESS OF
ONE AND A HALF INCHES TONIGHT. WILL KEEP MENTION OF HEAVY RAINFALL
POSSIBLE TONIGHT IN SOUTHERN TWO THIRDS OF CWA...BUT WILL NOT ISSUE
A FLOOD WATCH FOR TONIGHT AT THIS TIME.

BY WEDNESDAY MORNING...MCS WILL BE MOVING OFF TO OUR EAST...SO WILL
SLOWLY LOWER POPS THROUGH THE DAY FROM WEST TO EAST. THEN BY
WEDNESDAY NIGHT...FRONTAL BOUNDARY WILL LIFT NORTH OF CWA...SO KEPT
MOST OF CWA DRY WITH A LOW CHANCE POP IN THE FAR NORTHERN COUNTIES.

LONG TERM...THURSDAY THROUGH MONDAY...
EXTENDED MODELS COMING INTO BETTER AGREEMENT WITH BOUNDARY PUSHING
BACK NORTH OF CWA BY THURSDAY...SO BACKED OFF ON POPS ALL LOCATIONS
WITH BEST CHANCES OF ANY PCPN IN THE NORTH ONLY FOR THURSDAY THROUGH
FRIDAY NIGHT. DRY EVERYWHERE SATURDAY AND SATURDAY NIGHT BEFORE
FRONT MAKES ITS WAY BACK INTO ILLINOIS ON SUNDAY AND MONDAY.
&&

.ILX WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
&&

BARKER/BYRD

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LINCOLN IL
1100 AM CDT TUE MAY 18 2004

ILZ027>031-036>038-040>057-061>063-066>068-071>073-191100-
CASS-CHAMPAIGN-CHRISTIAN-CLARK-CLAY-COLES-CRAWFORD-CUMBERLAND-
DE WITT-DOUGLAS-EDGAR-EFFINGHAM-FULTON-JASPER-KNOX-LAWRENCE-LOGAN-
MACON-MARSHALL-MASON-MCLEAN-MENARD-MORGAN-MOULTRIE-PEORIA-PIATT-
RICHLAND-SANGAMON-SCHUYLER-SCOTT-SHELBY-STARK-TAZEWELL-VERMILION-
WOODFORD-
INCLUDING THE CITIES OF...BLOOMINGTON...CHAMPAIGN...DANVILLE...
DECATUR...EFFINGHAM...FLORA...GALESBURG...HAVANA...JACKSONVILLE...
LAWRENCEVILLE...LINCOLN...MATTOON...PEORIA...SHELBYVILLE...
SPRINGFIELD AND TAYLORVILLE
1100 AM CDT TUE MAY 18 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL AND SOUTHEAST ILLINOIS.

.DAY ONE...THIS AFTERNOON AND TONIGHT...

A SLOW MOVING FRONTAL BOUNDARY WILL SLOWLY MOVE SOUTH ACROSS CENTRAL
ILLINOIS THIS AFTERNOON AND EVENING...AND REACH NEAR INTERSTATE 70
BY MIDNIGHT. THIS FRONT COLLIDING WITH A WARM...MOIST AND UNSTABLE
AIR MASS WILL PRODUCE MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
ACROSS CENTRAL ILLINOIS THIS AFTERNOON AND TONIGHT. THERE IS A
SLIGHT RISK THAT SOME OF THESE STORMS COULD BECOME SEVERE ACROSS
CENTRAL AND SOUTHEAST ILLINOIS. THE PRIMARY THREAT WITH THESE STORMS
WILL BE DAMAGING WINDS AND LARGE HAIL.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY...

A FRONTAL BOUNDARY WILL REMAIN ACROSS CENTRAL ILLINOIS WEDNESDAY AND
THEN LIFT NORTHWARD ON THURSDAY. THIS BOUNDARY WILL CONTINUE TO
INTERACT WITH WARM...MOIST AIR AND PRODUCE PERIODS OF THUNDERSTORMS
THROUGH MOST OF THE WEEK. THERE IS A SLIGHT RISK THAT SOME OF THESE
STORMS COULD BECOME SEVERE WEDNESDAY ACROSS ALL OF CENTRAL
ILLINOIS...AND AGAIN ON THURSDAY NORTH OF INTERSTATE 72.

.SPOTTER ACTIVATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED THROUGH TONIGHT.

&&

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

HTTP://WWW.CRH.NOAA.GOV/ILX. THIS ADDRESS IS ALL IN LOWER CASE.

AUTEN/HUETTL