Severe Thunderstorm Warning 45, NWS Lincoln, IL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
255 AM CDT MON APR 23 2001

SFC ANALYSIS SHOWS SFC LOW PRESS IN WRN IA NR OMA.  TRAILING CLD
FRONT/DRY LINE LOCATED ACROSS ERN KS FROM OMA TO TOP TO TUL.  SQUALL
LINE AHEAD OF THIS FRONT HAS PRETTY MUCH FALLEN APART IN CEN MO WITH
SOME SCT DEBRIS LEFT.  QUESTIONS TDY WILL INCLUDE TSRA CHC
...POSSIBLE SVR WX...LATER TDY WITH FROPA AND TEMPS.

88D SHOWS THAT LEFT OVER SHRA...DIMINISHING QUICKLY ACROSS ERN MO.
WIL MAKE A PRESS TIME DICISION ON WHETHER TO KEEP ANY EARLY MORNING
PCPN WORDING...BUT FEEL ATTM SPRINKLES WILL PROBABLY COVER THIS.
MAIN ACTION COMES DURING THE MAIN PART OF THE DAY AS SYS IN THE WEST
APPOACHES. MODELS ARE ALL IN GOOD AGREEMENT WITH SFC LOW PULLING
NORTH INTO WI TDY WITH THE TRAILING FRONT MAKING QUICK PROGRESS
ACROSS MO EARLY TDY...REACHING THE MISS RVR BY 15Z. PRESS GRADIENT
TIGHTENS AHEAD OF THE FRONT ACROSS THE AREA...WITH 50-60KT LLJ JUST
OFF THE SFC.  AM A LITTLE CONCERNED WITH 850H WIND MIXING DOWN TO
THE SFC AFTER SUNRISE...PRODUCING WINDS REACHING ADVIS CRITIERIA.
STILL KINDA HESITANT ON WHETHER TO ISSUE THE NPW...AS FEEL STRONGEST
WINDS WILL BE CLOSER TO THE SFC LOW TRACK IN ERN IA. BUT WILL GO
AHEAD AND RAISE THE ADVIS DURING THE DAYLIGHT HOURS...AS WINDS WILL
BE CLOSE ENOUGH TO SUPPORT ADVIS.

AS FOR FRONT MOVING ACROSS CEN IL DURING THE MAIN HEATING PART OF
THE DAY.  SFC MOISTURE IS RATHER LIMITED ATTM WITH ONLY MID 50S
DWPTS AROUND.  ETA/MESOETA APPEARS OVERDONE WITH SFC DWPTS LATER
TODY BUT SHOWS CAPES BECOMING MARGINALLY UNSTABLE THIS AFTN...WITH
VALUES AROUND 1000-1500 J/KG.  LOW LVL FORCING IS ALSO MARGINAL FOR
TSRA SUPPORT.  BUT UPR LVL DYNAMICS LOOK IMPRESSIVE ENOUGH TO
SUPPORT SVR WX THREAT IF ANY STORMS GET GOING.  WITH THAT
SAID....EXPECT SOME SCT TSRA TO EXPLODE OVER CEN IL(MAINLY EAST OF
I-55) LATER TDY AROUND 18Z WITH DAMAGING WINDS AND HAIL THE MAIN
THREAT.

WITH DELAY OF FRONT UNTIL MID DAY.  GUID TEMPS LOOK TO BE OUT TO
LUNCH FOR HIGHS TDY.  GUID HIGH TEMPS VERY CLOSE TO CURRENT VALUES
AT 07Z.  WITH PARTLY SUNNY SKY EXPECTED AHEAD OF THE FRONT...TEMPS
JUST SLIGTLY LESS THAN YESTERDAY.  GOING ZONES HAVE A NICE HANDLE ON
THIS...BUT MAY ADJUST PIA GROUP SLIGHTLY HIGHER.

FROPA MOVES THROUGH CEN IL BEFORE 00Z WITH DRY SLOT MOVING RAPIDLY
ACROSS THE AREA.   WRAP AROUND CLOUDS MAY LEAD TO SOME -DZ IN NWRN
SECTIONS OF CEN IL THIS EVENING WITH SOME LOW CLOUDS AROUND
OVERNIGHT.

HIGH PRESS AND CLRG SKIES COME IN FOR TUES...WITH THE ONLY CONCERN
THE CHILLY TEMPS.  UPR LVL NW FLOW BRINGS ANOTHER WK S/WV AND SFC
LOW ACROSS CEN IL ON WED.  PCPN CHCS WITH THIS SYS APPEAR RATHER
LOW...AS MOISTURE WITH IT IS RATHER LOW...WITH GULF CUT OFF BY HIGH
PRES.  WILL DROP CHC POPS IN SERN IL FOR WED AS BEST CHC FOR ANY
MEASUREABLE PCPN STAYS FURTHER NORTH.

REST OF THE EXTENDED LOOKS OKAY...BUT NOT TOO CONFIDANT ON PCPN CHC
ON SAT EITHER AS GULF REMAINS CUT OFF.

...PRELIMINARY NUMBERS FOR COORDINATION ONLY...

SPI TB 080/044 062/042 065 22620
PIA TB 078/040 060/040 064 22620
DEC TB 080/044 062/042 065 22620
CMI TB 084/045 061/042 065 22730
MTO TB 084/045 063/041 063 22730
LWV TB 088/048 065/042 064 22740

.ILX...WIND ADVIS FOR ALL OF CEN IL TODAY.

KETCHAM

ILZ027>031-036>038-040>057-061>063-066>068-071>073-231600-

HAZARDOUS WEATHER OUTLOOK FOR CENTRAL ILLINOIS
NATIONAL WEATHER SERVICE LINCOLN IL
601 AM CDT MON APR 23 2001

THERE IS A SLIGHT RISK OF SEVERE WEATHER ACROSS ALL OF CENTRAL AND
SOUTHEAST ILLINOIS TODAY.

A STRONG COLD FRONT WILL MAKE ITS WAY ACROSS CENTRAL ILLINOIS TODAY.
A LINE OF STRONG THUNDERSTORMS IS EXPECTED TO DEVELOP ALONG THE
COLD FRONT LATER TODAY.  SOME OF THESE STORMS COULD PRODUCE SEVERE
WEATHER...WITH DAMAGING WINDS AND LARGE HAIL BEING THE MAIN THREAT.

STRONG GUSTY WINDS WILL ALSO BE A CONCERN TODAY. SUSTAINED WINDS OF
25 TO 35 MPH ARE POSSIBLE WITH WIND GUSTS AS HIGH AS 45 MPH.

KETCHAM