885 
FXUS63 KILX 182052
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
245 PM CST TUE DEC 18 2001

FORECAST CHALLENGES INCLUDE CHANCES FOR LIGHT PCPN LATE TONIGHT/WED 
MORN AND THEN THE STORM SYSTEM FOR THE WEEKEND. LATEST SFC ANALYSIS 
INDICATED A COLD FRONT FROM CENT LAKE SUP-ECENT IA TO A LOW IN SRN 
KS. THIS BOUNDARY WILL MOVE INTO WCENT IL AROUND MIDNIGHT AND 
ECENT/SE SECTIONS AROUND DAYBREAK. THE FRONT IS XPCTD TO BE DRY... 
BUT A SHORTWAVE LAGGING BEHIND THE BOUNDARY WILL APPCH CENT IL BY 
MORNING AND SQUEEZE OUT SOME LIGHT PCPN. BUFKIT FCST SOUNDINGS... 
CROSS SECTIONS AND THICKNESS PROGS AGREE THAT AT THE ONSET VERY 
LIGHT RAIN IS XPCTD...THEN MIX WITH AND CHANGE TO LIGHT SNOW AS THE 
DRY AIR THAT IS OVERCOME UNDERGOES EVAPORATIONAL COOLING. THIS IS 
ONLY XPCTD TO LAST FOR A SHORT PERIOD OF TIME AS THE SHORTWAVE 
QUICKLY MOVES EAST AND THE LOW LEVELS RAPIDLY DRY OUT AND COOL.
WILL MENTION SPRINKLES/FLURRIES FOR WESTERN HALF OF REGION TOWARD 
DAYBREAK...AND THEN GO WITH 30 POPS MUCH OF CENT IL IN THE MORNING 
FOR LIGHT SNOW WEST-RAIN/SNOW MIX EAST. TIGHT GRADIENT BEHIND THE 
FRONT AND COLD ADVECTION WARRANTS BLUSTERY WORDING FOR WED.

QUIET WEATHER PATTERN TO SETTLE IN FOR LATE WED INTO FRIDAY AS A WNW 
UPPER FLOW DOMINATES AND HIGH PRESSURE SETTLES IN. WITH THE HIGH 
BEING OF PACIFIC ORIGIN WILL SEE AN INCREASE IN TEMPS THU-FRI ABOUT 
10 DEGREES ABV SEASONAL NORMS.

THE FCST GETS A BIT TRICKY TOWARD THE WEEKEND AND INTO THE HOLIDAY 
AS THE MEDIUM RANGE MODELS ARE ALL OVER THE PLACE WITH THEIR 
SOLUTIONS. THE MRF STARTS OUT WITH SOME RUN-RUN CONSISTENCY THEN 
DIVERGES TOWARD SATURDAY WITH A LOW TRACK FARTHER SOUTH THAN 
YESTERDAY. THE CANADIAN MODEL IS ALSO FARTHER SOUTH...BUT THE ECMWF
IS THE FARTHER NORTH. THE 12Z AVN 120 HOUR FCST FOR SUN MORNING IS 
ALSO TAKING THE SYSTEM TO THE NORTH. WILL MAKE FEW CHANGES TO THE 
4-7 DAY FCST (22ND-25TH) BASED ON THE LOW CONFIDENCE/UNCERTAINTY 
INVOLVED WITH THE SOLUTIONS...WHICH CAN NOT RESOLVE THE SEPERATE 
NRN/SRN STREAMS OF ENERGY AND WHEN/IF THEY PHASE.
   
...PRELIMINARY CCF NUMBERS FOR COORD PURPOSES ONLY...

SPI BA 033/040 022/042 027 23130
PIA BA 033/038 020/041 025 23230
DEC BA 033/039 022/042 027 23130
CMI BA 033/038 020/041 024 23130
MTO BA 034/040 020/042 024 23130
LWV BA 036/043 023/045 027 23020

.ILX...NONE.

$$

MILLER