Hail and Damaging Winds in Illinois, May 17, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
245 PM CDT WED MAY 17 2006

.DISCUSSION...
12Z SHORT RANGE MODELS SIMILAR THROUGH FRI NIGHT WITH SHORT WAVES
REINFORCING STRONG UPPER LEVEL TROF OVER THE NE 1/3RD OF THE U.S.
AND KEEPING CHANCES OF CONVECTION GOING THIS EVENING AND AGAIN THU
AFTERNOON AND THU EVENING. MODELS DIFFER THIS WEEKEND WITH GFS MORE
AGGRESSIVE BRINGING SHORT WAVES AND ASSOCIATED QPF FIELDS EAST INTO
IL WHILE OTHER MODELS ARE DRIER. IL IS IN A NW UPPER LEVEL FLOW NEXT
WORK WEEK WITH UPPER LEVEL RIDGE WEST AND UPPER LEVEL TROF STAYING
OVER THE NE U.S. APPEARS DRY WITH TEMPS WARMING BACK TO OR A LITTLE
ABOVE NORMAL.

SHORT TERM...TONIGHT THROUGH SUNDAY...
RADAR MOSAIC SHOWING CONVECTION DEVELOPING ACROSS CENTRAL/NORTHERN
IL/IN AND INTO EASTERN IA AND WI. THIS CONVECTION AHEAD OF A COLD
FRONT OVER SE WI AND CENTRAL IA AND VIGOROUS UPPER LEVEL TROF OVER
WI AND MID/UPPER LEVEL JET DIVING SOUTHWARD INTO IL. AIR MASS IS
UNSTABLE WITH LIFTED INDICES OF MINUS 3 TO 6C AND STEEP LAPSE RATES.
SURFACE TEMPS IN THE LOW TO MID 70S WHILE DEWPOINTS 45 TO 55F.

COLD FRONT TO SLIDE QUICKLY SE THROUGH CENTRAL IL THIS EVENING AND
INCREASED POPS ACROSS AREA THIS EVENING AND WENT DRY AFTER MIDNIGHT.
SEVERE THUNDERSTORM WATCH BEING ISSUED FOR LARGE PART OF CENTRAL IL
UNTIL 9 PM FOR PRIMARILY LARGE HAIL. MUCH OF AREA IN A SLIGHT RISK
FOR SEVERE STORMS THIS EVENING. THIS DUE TO STEEP LAPSE RATES AND
UNSTABLE AIR MASS. STRONGEST STORMS WILL OCCUR OVER NE AREAS WHERE
STRONGER SHORT WAVE PASSES. COLD FRONT A QUICK MOVER SO WENT DRY
OVERNIGHT AND THU MORNING. THEN PROB30 CHANCE OF CONVECTION OVER
CENTRAL/SE IL THU AFTERNOON AND EVENING AS MORE SHORT WAVE ENERGY
DIVES SSE ACROSS IL AND INTERACTS WITH DAYTIME HEATING TO PRODUCE
MORE SCATTERED CONVECTION. STRONGEST SHORT WAVE ENERGY APPEARS TO
PASS JUST NE OF CENTRAL IL WHERE STRONGER STORMS POSSIBLE.

UPPER LEVEL RIDGE NUDGING EAST TOWARD IL FRI AND SHOULD KEEP THE
AREA DRY WITH ANY DIURNAL SHOWERS FRI AFTERNOON/EARLY FRI EVENING NE
OF AREA. HAVE SLIGHT CHANCE OF CONVECTION SAT...PROB30 ACROSS AREA
SAT NIGHT AND SLIGHT CHANCE SE OF THE IL RIVER SUNDAY. THIS DUE TO
SHORT WAVE ENERGY MOVING EAST ACROSS AREA FROM THE CENTRAL PLAINS.
GFS MAY BE TOO STRONG WITH SHORT WAVE AND ASSOCIATED HEAVIER QPF
FIELDS THOUGH.

LONG TERM...SUNDAY NIGHT THROUGH WEDNESDAY...
MEDIUM AND LONG RANGE MODELS ARE IN FAIR AGREEMENT WITH STRONG UPPER
LEVEL TROF...WITH STRONG UPPER LEVEL RIDGE OVER THE PLAINS/WESTERN
US AND UPPER LEVEL TROF OVER THE ATLANTIC STATES. THIS PUTS IL IN A
NW UPPER LEVEL FLOW. GFSLR HAS A STRONGER UPPER LEVEL TROF CLOSER TO
IL BUT STILL DRY OVER IL BUT COOLER. GFS ENSEMBLES AND ECMWF ARE
FURTHER EAST WITH THIS TROF AND DRY AND WARMER AND WILL LEAN TOWARD
THIS SCENERIO. CANADIAN MODEL IS IN BETWEEN ECMWF AND GFS. MEX HIGHS
APPEAR TOO COOL AND WENT A FEW DEGREES WARMER ESPECIALLY FOR HIGHS.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

HUETTL

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LINCOLN IL
1135 AM CDT WED MAY 17 2006

ILZ027>031-036>038-040>057-061>063-066>068-071>073-181015-
KNOX-STARK-PEORIA-MARSHALL-WOODFORD-FULTON-TAZEWELL-MCLEAN-
SCHUYLER-MASON-LOGAN-DE WITT-PIATT-CHAMPAIGN-VERMILION-CASS-
MENARD-SCOTT-MORGAN-SANGAMON-CHRISTIAN-MACON-MOULTRIE-DOUGLAS-
COLES-EDGAR-SHELBY-CUMBERLAND-CLARK-EFFINGHAM-JASPER-CRAWFORD-
CLAY-RICHLAND-LAWRENCE-
1135 AM CDT WED MAY 17 2006

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

A STRONG UPPER-LEVEL DISTURBANCE AND ASSOCIATED COLD FRONT WILL
MOVE ACROSS ILLINOIS LATE THIS AFTERNOON AND EVENING. SCATTERED
THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG AND AHEAD OF THE
FRONT. DUE TO COLD TEMPERATURES AT MIDDLE LEVELS OF THE
ATMOSPHERE...HAIL IS LIKELY WITH THE STRONGER STORMS. SOME OF THE
HAIL MAY BE LARGER THEN NICKELS. IN ADDITION...THERE WILL ALSO BE
A THREAT OF WINDS IN EXCESS OF 60 MPH NEAR THE STRONGER STORMS
LATE THIS AFTERNOON.

ALTHOUGH A FEW STORMS MAY DEVELOP AHEAD OF THE MAIN FRONT...THE
BEST CHANCES WILL OCCUR WITH THE BOUNDARY AS IT MOVES THROUGH
PEORIA AND BLOOMINGTON LATE THIS AFTERNOON AND
SPRINGFIELD...DECATUR...AND CHAMPAIGN DURING THE EARLY EVENING.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THUNDERSTORMS WILL ONCE AGAIN BE POSSIBLE ON THURSDAY. AT THIS
TIME...SEVERE WEATHER IS NOT EXPECTED WITH THESE STORMS.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NEEDED FROM 3 PM THROUGH 8 PM.

&&

THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC AND CLIMATE
INFORMATION IS AVAILABLE ON THE WEB AT
HTTP://WWW.WEATHER.GOV/LINCOLN. THIS ADDRESS IS ALL IN LOWER CASE.

BARKER