Severe Thunderstorm Warning 31, NWS Lincoln, IL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
214 AM CDT WED APR 24 2002

PLENTY OF CONCERNS NEXT 24 HOURS...WITH SEVERE WEATHER...ISOLATED
HEAVY RAINFALL...TEMPERATURES...AND TIMING OF PRECIPITATION.

LATEST 06Z SURFACE ANALYSIS PLACES SURFACE LOW ACROSS WESTERN
MINNESOTA WITH COLD FRONT EXTENDED FROM WESTERN MINNESOTA
SOUTHWEST INTO NORTHWEST KANSAS. A DRY LINE WAS IN THE
PANHANDLE OF TEXAS AND OKLAHOMA. LATEST 0615Z IR SATELLITE IMAGE
PLACES MOSTLY CLEAR SKIES ACROSS MOST OF ILLINOIS INTO GREAT LAKES
REGION. HOWEVER...SOME SOME LOW CLOUDS WITH THUNDERSTORMS WERE
ACROSS SOUTHERN MISSOURI. LATEST 0615Z W/V IMAGE PLACES S/W ACROSS
MISSOURI...AND SEVERAL OTHER S/WS WERE ACROSS WESTERN PLAINS STATES
INTO WYOMING. LATEST 0616Z KLSX RADAR PLACES THUNDERSTORMS ACROSS
SOUTHERN MISSOURI MOVING EAST.

MODELS FAIRLY SIMILAR WITH SOME TIMING AND STRENGTH DIFFERENCES OF
MAIN FEATURES. MODELS HAVE SLOWED DOWN THE COLD FRONT ACROSS CWA.
WILL USE MAINLY AN ETA OVERALL SOLUTION.

MODELS SLOW THE COLD FRONT WITH ETA MOVING COLD FRONT ACROSS CWA
WEDNESDAY AFTERNOON. ETA PLACES COLD FRONT ACROSS WESTERN MICHIGAN
SOUTHWEST INTO SOUTHERN ILLINOIS BY 00Z THU...HIGH PRESSURE IS THEN
ACROSS PLAINS STATES BY 18Z THU. ETA DEVELOPS TROUGH ACROSS MIDWEST
BY 00Z THU...AND ACROSS GREAT LAKES REGION BY 12Z THU. H50 LOW
IS ACROSS SOUTHERN CALIFORNIA AND RIDGE DEVELOPS ACROSS PLAINS
STATES BY 00Z FRI. ETA MOVES STRONG H50 S/W ACROSS SOUTHERN CANADA
INTO UPPER MIDWEST BY 00Z THU...MOVES EAST AND IS ACROSS CANADA INTO
NORTHEAST U.S. BY 00Z FRI. ETA MOVES H85 TEMPS TO +12 TO +14 BY 18Z
WED...+6 TO +12 H85 TEMPS BY 00Z THU...0 TO -2 H85 TEMPS BY 12Z
THU THRU 12Z FRI. ETA T/H CROSS SECTIONS INDICATING HIGH RH AT ALL
LEVELS BY 18Z ACROSS CENTRAL ILLINOIS AND BY 21Z ACROSS EASTERN
ILLINOIS...DECREASES RH AT ALL LEVELS BY 03Z THU. ETA MODEL SOUNDINGS
SHOWING PW/S TO 1.3 AND LI/S -3 TO -5 AHEAD OF COLD FRONT WEDNESDAY
AFTERNOON. ETA MODEL SOUNDINGS THEN KEEPS LOW RH AT ALL
LEVELS BY 06Z THU BUT THEN DEMONSTRATES RETURN OF HIGH RH AT MID AND
HIGH LEVELS BY 12Z FRI. ETA MOVES INTENSE S/W ACROSS NORTHERN IL INTO
WISCONSIN BY 00Z THU....EASTERN LAKE MICHIGAN BY 12Z THU. ETA 305K
ISENTROPIC SFC INDICATES DECENT ISENTROPIC LIFT AND COND PRES DEF
ACROSS CWA BY 18Z WED AND ACROSS SOUTHEAST ILLINOIS BY 00Z THU. ETA
300MB MOVES 130KT JET ACROSS NORTHERN PLAINS STATES INTO MIDWEST
BY 00Z THU...AND IS ACROSS NORTHERN ILLINOIS BY 18Z THU. EXPECT TO
SEE SCATTERED STRONG/SVR WX ACROSS CWA LATE THIS MORNING INTO LATE
AFTERNOON ACROSS CWA AND AGREE WITH SPC OUTLOOK.

A LITTLE CONCERNED ABOUT PCPN ON FRIDAY...HOWEVER WILL LEAVE ALONE
UNTIL FURTHER GUIDANCE.

TEMPERATURES TRICKY TODAY WITH WARM SURGE AHEAD OF COLD FRONT BUT
HAVE CLOUDS TO CONTEND WITH. WILL LEAN ON WARMER TEMPERATURES.

...PRELIMINARY CCF FOR COORDINATION PURPOSES...

SPI TB 072/037 055/034 059 13+21
PIA TB 069/035 054/033 058 13+11
DEC TB 072/037 055/034 059 13+21
CMI TB 073/035 055/033 058 13+31
MTO TB 073/037 056/035 060 13+31
LWV TB 075/039 058/037 061 13+41

.ILX...NONE.

EH

ILZ027>031-036>038-040>057-061>063-066>068-071>073-241800-

HAZARDOUS WEATHER OUTLOOK FOR CENTRAL ILLINOIS
NATIONAL WEATHER SERVICE LINCOLN IL
1100 AM CDT WED APR 24 2002

...THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS THIS AFTERNOON
AND THIS EVENING ACROSS CENTRAL AND SOUTHEAST ILLINOIS...

SEVERE THUNDERSTORMS ARE POSSIBLE ALONG A COLD FRONT THAT WILL BE
MOVING THROUGH CENTRAL ILLINOIS LATER THIS AFTERNOON INTO THIS
EVENING. THE PRIMARY SEVERE WEATHER THREAT WILL BE LARGE HAIL AND
DAMAGING WINDS BETWEEN 2PM AND 7PM.

REMAIN ALERT TO RAPIDLY CHANGING WEATHER CONDITIONS. MONITOR NOAA
WEATHER RADIO...OR COMMERCIAL RADIO OR TELEVISION FOR THE LATEST
WEATHER FORECASTS.