FXUS63 KILX 031151
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
551 AM CST THU DEC 3 2009

.DISCUSSION...
ISSUED 330 AM CST THU DEC 3 2009

00Z SHORT RANGE MODELS ARE IN FAIR AGREEMENT INTO THIS WEEKEND AS
UPPER LEVEL TROF DIGS INTO IL FRI...THE LIFTS OUT THIS WEEKEND.
COOLER TEMPERATURES WILL PREVAIL THE NEXT SEVERAL DAYS. FORECAST
CONCERN IS CLOUD COVER NEXT FEW DAYS. THEN ADDRESSING NEXT CHANCE
OF MEASURABLE PRECIPITATION NEXT WORK WEEK.

09Z/3 AM SURFACE MAP SHOWS STRONG 989 MB LOW PRESSURE DEEPENING
OVER EASTERN LAKE ERIE WITH ITS COLD FRONT OVER EASTERN KY/TN.
1035 MB CANADIAN HIGH PRESSURE WAS OVER THE NORTHERN ROCKIES AND
RIDGING ACROSS THE HIGH PLAINS INTO TX. BREEZY NW WINDS USHERING
COOLER AIR INTO IL BETWEEN THESE TWO WEATHER SYSTEMS WITH
TEMPERATURES RANGING FROM THE UPPER 20S AND LOWER 30S WEST OF
PEORIA AND SPRINGFIELD TO THE UPPER 30S IN SE IL. SPOTTY
DRIZZLE AND FLURRIES ARE NORTH AND EAST OF CENTRAL IL BUT BROKEN
LOW CLOUDS COVER MUCH OF IL WITH A LARGE BREAK OVER WEST CENTRAL
AND SW IL NEAR THE MS VALLEY. ALOFT A STRONG 526 DM 500 MB LOW WAS
ALONG THE MN/DAKOTAS BORDER AND ASSOCIATED WITH A LARGE UPPER
LEVEL TROF FROM HUDSON BAY INTO THE CENTRAL U.S.

SHORT TERM...TODAY THROUGH SATURDAY NIGHT.

BREEZY NW WINDS AND CHILLY CONDITIONS WILL PREVAIL TODAY WITH
MOSTLY CLOUDY SKIES. HIGHS IN THE MID TO UPPER 30S WITH
LAWRENCEVILLE NEAR 40F. STRONG SHORT WAVE IN EASTERN SD WILL MOVE
TOWARD THE IL/IA BORDER BY SUNSET AND BRING CHANCE OF FLURRIES
INTO THE IL RIVER VALLEY NORTH OF I-72 LATER TODAY. MAIN UPPER
LEVEL TROF MOVES INTO IL BY SUNSET FRI WITH COLDEST HIGHS EXPECTED
THEN IN THE LOW TO MID 30S AND FOLLOWED COOLER MET HIGHS FRI.
CHANCE OF FLURRIES NORTH OF I-72 TONIGHT WITH LOWS IN THE LOW TO
MID 20S. FLURRIES SHIFTS NORTH OF CENTRAL IL FRI AND MORE SUNSHINE
WILL BE POSSIBLE SW AREAS FRI WHILE STAYING MOSTLY CLOUDY NE OF
LINCOLN.

SURFACE HIGH PRESSURE RIDGE NOSING INTO IL AND THE OHIO VALLEY
FROM TX SAT WHILE UPPER LEVEL TROF DAMPENS AND PASSES EAST OF IL.
THIS SHOULD BRING MORE SUNSHINE TO CENTRAL/SE IL SAT BUT STILL
CHILLY WITH HIGHS IN THE MID TO UPPER 30S AFTER LOWS FRI NIGHT IN
THE UPPER TEENS AND LOWER 20S. 

LONG TERM...SUNDAY THROUGH WEDNESDAY.

HIGH PRESSURE SHIFTS INTO THE EASTERN STATES SUNDAY WITH
SOUTHERLY FLOW OVER IL AND TEMPERATURES MODIFY A BIT INTO THE
LOWER 40S EXCEPT UPPER 30S FROM I-74 NE. GFS AND ECMWF MODELS
TRENDING QUICKER EJECTING A SHORT WAVE INTO IL SUNDAY NIGHT WITH
CHANCE OF LIGHT SNOW ESPECIALLY OVERNIGHT SUNDAY NIGHT. THIS
FEATURE THEN SHIFTS NORTH OF CENTRAL IL DURING MON WHERE BETTER
CHANCES OF LIGHT SNOW WILL BE. HIGH PRESSURE OVER IL MON NIGHT
BRINGS DRY WEATHER. THEN A STRONGER STORM SYSTEM TO EJECT INTO THE
SE STATES TUE/WED WITH NEXT CHANCE OF PRECIPITATION OVER
CENTRAL/SE IL. LOOKS LIKE A MIX OF PRECIPITATION THOUGH NW AREAS
IN COLDER AIR WILL SEE MORE SNOW THAN RAIN. HEAVIER PRECIPITATION
STILL APPEARS TO BE IN SE IL AND THIS WEATHER SYSTEM WILL NEED TO
BE MONITORED.

HUETTL

&&

.AVIATION...
ISSUED 551 AM CST THU DEC 3 2009

A SLOW MOVING AREA OF LOW PRESSURE...CENTERED OVER THE EASTERN
GREAT LAKES...WILL DOMINATE THE WEATHER ACROSS THE CENTRAL
ILLINOIS TERMINALS THROUGH THE 12Z TAF PERIOD. MOISTURE AND
MULTIPLE DISTURBANCES WRAPPING AROUND THIS FEATURE WILL KEEP CIGS
IN PLACE FOR MUCH OF THE DAY AND INTO THE NIGHT...WITH A FEW SNOW
FLURRIES POSSIBLE...THOUGH KSPI/KDEC/KCMI ARE LIKELY TO SCATTER
OUT TONIGHT. IN ANY CASE...THE CIGS WILL PREDOMINANTLY BE IN THE
VFR CATEGORY AND ANY FLURRIES SHOULD NOT CAUSE A VISIBILITY
RESTRICTION.

WINDS WILL BECOME GUSTY OUT OF THE NORTHWEST TODAY AS DIURNAL
MIXING COMMENCES. THE GUSTS SHOULD FALL OFF TONIGHT AS DIURNAL
MIXING IS LOST AND THE PRESSURE GRADIENT RELAXES IN THE WAKE OF
THE SLOWLY DEPARTING GREAT LAKES LOW.

BAK
&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$