Severe Thunderstorm Warning 170, NWS Lincoln, IL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
230 PM CDT FRI AUG 2 2002

MODELS HAVE DIVERAGED FROM LAST FEW RUNS WHEN THEY WERE FAIRLY
SIMILAR. ETA IS DRIER AND WARMER THRU MON WHILE AVN MOST AGGRESSIVE
WITH BRINGING A BACKDOOR COLD FRONT THRU CENTRAL IL MON WITH MORE
QPF AND COOLER TEMPS. EXTENDED MODELS ARE TRENDING COOLER TOO. WILL
LEAN WITH THE ETA MODEL AS STRONG UPPER LEVEL RIDGE NEARBY INTO NEXT
WEEK BUT STILL THINK ETA 2M TEMPS A FEW DEGREES TOO WARM ESPECIALLY
FOR HIGHS. FORECAST CHALLENGE IS ADDRESSING HOT TEMPS AND IF CHANCE
OF CONVECTION NEEDED IN CURRENT DRY FORECAST.

18Z SURFACE ANALYSIS HAS WEAK LOW PRESSURE NEAR DANVILLE WITH A
FRONTAL BOUNDARY EXTENDING SW JUST SOUTH OF KSTL AND INTO NORTH OK.
DEWPOINTS STILL FAIRLY HIGH ACROSS CENTRAL IL...EVEN RISING IN THE
NORTH WITH READINGS IN THE 70S. TEMPS IN THE 80S WITH A FEW LOWER
90S SOUTH OF I-70. HEAT INDICIES UP TO 100 TO 110 FROM I-57 EAST. A
FEW SHOWERS BEGINNING TO DEVELOP ALONG FRONT NEAR KCMI SSW TO
EFFINGHAM AND MORE WIDESPREAD IN SE MO.

WILL HAVE SLIGHT CHANCE OF CONVECTION EARLY THIS EVENING SE...ADDING
A FEW MORE COUNTIES TO INCLUDE KMTO. OTHERWISE FRONT TO DISSIPATE AS
IT MOVES THRU SE CWA THIS EVENING WITH DRIER AIR FILTERING INTO
AREAS N OF I-70 AS HIGH PRESSURE OVER MN MOVES ACROSS THE GREAT
LAKES WITH NE FLOW. DEWPOINTS SLIP INTO THE UPPER 50S N OF KPIA
OVERNIGHT. LOWS TO RANGE FROM THE MID 60S NW AND LOWER 70S SE. HIGH
PRESSURE SLIPS OFF TO THE EAST THIS WEEKEND WITH RETURN SOUTH FLOW
AND MORE HUMID AIR WITH DEWPOINTS BACK INTO THE LOWER 70S. GUIDANCE
TEMPS SIMILAR THRU THIS WEEKEND EXCEPT MET/ETA A FEW DEGREES WARMER.
WILL FOLLOW FWC/MAV WHICH IS UP A DEGREE OR SO FROM YESTERDAYS RUN.
HIGHS 90 TO 95 THIS WEEKEND AND HEAT INDICES RANGE FROM 95 TO 105
WITH HOTTEST READINGS SW CWA.

WILL INTRODUCE PROB30 POPS NORTH SUNDAY NIGHT AND ACROSS CENTRAL IL
MON AS BACK DOOR COLD FRONT MOVES TOWARD AREA. ETA STILL KEEPS QPF N
OF I-80 SUNDAY NIGHT WITH SOME LIGHT QPF ALONG I-74 MON. THINK AVN
TOO AGGRESSIVE WITH ITS LIKELY POPS ON MON AND COOLER TEMPS AND WILL
LEAN TOWARD ETA WITH 594 DM 500 MB RIDGE JUST WEST OF IL. FRONT WILL
PROBABLY WASH OUT AGAIN OVER CENTRAL/SOUTHERN IL. MEX AND MRF COOL
HIGHS INTO THE 80S NEXT WEEK BUT FEEL THIS MAY BE TOO COOL GIVEN
STRONG UPPER LEVEL RIDGE NEARBY. WILL KEEP HIGHS IN THE UPPER 80S
AND LOWER 90S. ECMWF IS MOST CONSISTENT WITH STRONG RIDGE NEARBY.

SPI BB 068/093 074/094 073 07111
PIA BB 066/092 072/093 073 07111
DEC BB 068/092 073/094 073 07111
CMI BB 067/090 070/092 072 07111
MTO BB 069/092 072/093 073 07221
LWV BB 072/095 073/095 074 07221

.ILX...NONE.

BARBUSH/HUETTL