Tornadoes and Flash Flooding in Illinois, May 10, 2003

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
300 AM CDT SAT MAY 10 2003

HIGHLIGHT OF FORECAST PACKAKE IS ANOTHER DAY OF SEVERE WEATHER INTO
TONIGHT ALONG WITH HEAVY RAINS. ONGOING THUNDESTORMS OVER
EASTCENTRAL IL EARLY THIS MORNING THAT WERE SEVERE EARLIER WITH
SEVERAL LARGE HAIL REPORTS UP TO SOFTBALL SIZE. YET ANOTHER ROUND
EXPECTED LATER TODAY AND TONIGHT ESPECIALLY THIS EVENING. SPC DAY1
OUTLOOK CONTINUES TO HAVE IL IN A MODERATE RISK FOR CHANCE OF
SUPERCELLS WITH LARGE HAIL...DAMAGING WIND GUSTS AND POSSIBLE
TORNADOES. THIS WILL BE THE 5TH DAY OF SEVERE WEATHER IN THE PAST
WEEK

SYNOPTICALLY MODELS SIMILAR WITH NEGATIVELY TILTED UPPER LEVEL TROF
PIVOTING FROM THE CENTRAL ROCKIES NE INTO THE GREAT LAKES TONIGHT
WHILE STRONG SURFACE LOW OVER THE OK PANHANDLE DEEPENS AS IT MOVES
NE INTO EAST KS BY 18Z AND INTO FAR NW IL BY 06Z TONIGHT BRINGING A
COLD FRONT EAST THRU THE STATE TONIGHT. ONGOING CONVECTION NORTH OF
I-70 TO GRADUALLY WEAKEN THIS MORNING AS LOW LEVEL JET WEAKENS AND
FOCUSED MORE TO THE SW CLOSER TO DEVELOPING LOW IN KS. SOME SUNSHINE
SHOULD APPEAR THIS AFTERNOON ALLOWING ATMOSPHERE TO BECOME VERY
UNSTABLE AGAIN WITH TROPICAL AIR MASS WITH TEMPS IN LOWER 80S AND
DEWPOINTS IN UPPER 60S AND LOWER 70S. LIFTED INDICES OF MINUS 4 TO
8C AND CAPES OF 1500 TO 3000 J/KG THIS AFTERNOON. 100 TO 120 KNOT
300 MB JET WILL ALSO PROVIDE UPPER LEVEL DIVERGENCE AND LIFT ACROSS
CENTRAL IL BY TONIGHT. WILL HAVE GOOD CHANCE OF CONVECTION TODAY
...THEN LIKELY AGAIN TONIGHT WITH COLD FRONT MOVING IN. FFG VALUES ARE
1 TO 2 INCHES PER HOUR AND 1.5 TO 2.5 INCHES IN 3 HOURS. THINK A FEW
SPOTS COULD REACH THESE VALUES...BUT DO NOT WIDESPREAD ENOUGH IN
CENTRAL IL FOR A FLOOD WATCH. BEST ORGANIZED CONVECTION TODAY IS
EAST OVER INDIANA AND SW ACROSS MO/KS. CONVECTION IS ALSO MOVING
ALONG TO THE NORTHEAST. SEVERE RISK LOOKS BEST THIS EVENING FOR ILX
CWA...THEN SHIFTS EAST OVERNIGHT AS FRONT MOVES THRU. GFS STILL
APPEARS TOO QUICK WITH FRONT GIVEN AMPLIFIED UPPER LEVEL PATTERN.

COOLER AND BREEZY ON MOTHERS DAY WITH A FAIR AMOUNT OF CLOUDINESS.
PROB30 CHANCE OF SHOWERS NORTH OF I-70 WITH STRONG SURFACE AND UPPER
LEVEL LOW OVER THE WESTERN GREAT LAKES. TEMPS NEARLY 20 DEGREES
COOLER WITH HIGHS IN THE LOWER TO MIDDLE 60S MOST AREAS. HIGH
PRESSURE BUILDING EAST INTO THE MS VALLEY MON TO BRING MOSTLY CLEAR
TO PARTLY CLOUDY SKIES WITH ANOTHER SEASONABLY COOL DAY IN THE
60S.

THANKS FOR THE SEVERE WEATHER COORDINATION SPC.

.ILX...NONE.

HUETTL

ILZ027>031-036>038-040>057-061>063-066>068-071>073-111100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LINCOLN IL
609 AM CDT SAT MAY 10 2003

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

.DAY ONE...TODAY AND TONIGHT

A MAJOR SEVERE WEATHER OUTBREAK IS EXPECTED ACROSS PORTIONS OF
CENTRAL ILLINOIS LATE THIS AFTERNOON AND THIS EVENING. A WARM FRONT
STRETCHED ACROSS THE REGION THIS MORNING WILL CONTINUE TO BRING
EARLY DAY THUNDERSTORMS...SOME SEVERE...TO OUR REGION. THE MAIN
MORNING SEVERE WEATHER RISK IS LARGE HAIL AND DAMAGING WINDS...MAINLY
AT LOCATIONS SOUTH OF A PEORIA TO BLOOMINGTON LINE AND WEST OF
INTERSTATE 57. THE WARM FRONT WILL LIFT NORTH OF CENTRAL ILLINOIS
THIS AFTERNOON AS LOW PRESSURE LIFTS NORTHEAST TOWARD THE MID
MISSISSIPPI RIVER VALLEY. SOUTH OF THE FRONT...AN INCREASINGLY
UNSTABLE ENVIRONMENT WILL INTERACT WITH THE LOW AND ITS ASSOCIATED
COLD FRONT TO PRODUCE SEVERE THUNDERSTORMS ACROSS ILLINOIS FROM LATE
THIS AFTERNOON THROUGH THE EVENING. THE GREATEST THREAT OF SEVERE
WEATHER...WITH THE POTENTIAL OF TORNADOES...WILL BE AT LOCATIONS
ROUGHLY NORTHWEST OF A SPRINGFIELD TO CHAMPAIGN LINE. THE MAIN
THREAT ACROSS THE REMAINDER OF CENTRAL AND SOUTHEAST ILLINOIS WILL
BE DAMAGING WINDS AS THE COLD FRONT MOVES THROUGH DURING THE
EVENING.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER INFORMATION WOULD BE USEFUL THIS MORNING...MAINLY SOUTH OF A
PEORIA TO CHAMPAIGN LINE. IN ADDITION...SPOTTER ACTIVATION WILL BE
NEEDED LATE THIS AFTERNOON...AND THIS EVENING.

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

HTTP://WWW.CRH.NOAA.GOV/ILX (ALL IN LOWER CASE)

PLAHMER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LINCOLN, IL
213 AM CDT SAT MAY 10 2003

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0205 AM    MAROA                     IL   .75 INCH HAIL
05/10/03   MACON                          REPORTED BY MACON COUNTY
                                          SHERIFF

HJS

ILZ027>031-036>038-040>051-053-100930-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE LINCOLN IL
405 AM CDT SAT MAY 10 2003

...SEVERE THUNDERSTORM WATCH NUMBER 328 HAS BEEN ALLOWED TO
EXPIRE AT 4 AM ACROSS CENTRAL ILLINOIS...

THE SEVERE THUNDERSTORM WATCH THAT WAS IN EFFECT ACROSS MUCH OF
CENTRAL ILLINOIS NORTH OF I-70 HAS BEEN ALLOWED TO EXPIRE AT 4
AM. MORE SEVERE WEATHER IS POSSIBLE LATER TODAY AND THIS EVENING.

KH