[LeArc] Forecast Discussion : MLI@ 3/9/03 3:59:28 AM

[learc@mailman.qth.net]

The following weather message is provided by McDonough County E.S.D.A.


FXUS63 KDVN 091007
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
407 AM CST SUN MAR 9 2003

ARCTIC AIRMASS CONTINUES TO SETTLE INTO CWFA THIS MORNING WITH 
TEMPERATURES AT 09Z IN SINGLE DIGITS AND FALLING...WITH RECORD LOWS 
WITHIN REACH BEFORE SUNRISE. ARCTIC HIGH WAS CENTERED OVER EASTERN 
MT WITH RIDGE AXIS NUDGING SOUTHEAST ACROSS WESTERN IA INTO SOUTHERN 
IL. THIS RIDGE REMAINS IN PLACE TODAY WITH RESULTING NORTHWEST LOW 
LEVEL FLOW AND COLD AIR ADVECTION CONTINUING. SHORT TERM FORECAST 
CHALLENGE IS JANUARY LIKE COLD TEMPERATURES TODAY...THEN LONGER 
TERM PERIODIC CHANCES FOR LIGHT PRECIP AND WARMING TREND LATER THIS 
WEEK.

UPPER LEVEL NW FLOW WILL CONTINUE TODAY WITH COLD AIR ADVECTION 
LIMITED MAINLY TO BOUNDARY LAYER. SOME MID LEVEL MOISTURE AND WEAK 
JET LEVEL FORCING RESULTING IN MID LEVEL CLOUDS OVER SD INTO 
NORTHWEST IA THAT SATELLITE IMAGERY HAS SHOWN TENDENCY TO DISSIPATE 
AS THEY DRIFT SOUTHEAST. DO ANTICIPATE MORE SIGNIFICANT CLOUD COVER 
SOUTHWEST HALF TODAY WHERE WEAK MID LEVEL FORCING INDICATED ALONG 
H85 BAROCLINIC ZONE. LIMITED SUNSHINE WILL HAVE HARD TIME WARMING 
SNOW COVERED SURFACE AND HAVE TO OVERCOME NORTHWEST SURFACE FLOW 
PUSHING AIRMASS THAT REACHED HIGHS ONLY IN SINGLE DIGITS YESTERDAY. 
HAVE THUS TRIMMED BACK HIGHS TO JUST BELOW MAV...BUT NOT AS COLD AS 
MET RANGING FROM TEENS NORTH TO AROUND 20 SOUTH. WIND CHILL INDEX 
ALREADY AT ADVISORY CRITERIA EARLY THIS MORNING...AROUND MINUS 20...
IN EAST CENTRAL IA...AND WITH FALLING TEMPS OVER NEXT 3 HOURS...WILL 
GO AHEAD AND HOIST WIND CHILL ADVISORY FOR THIS MORNING FOR MAINLY 
NORTH OF INTERSTATE 80 IN EASTERN IA AND HIGHWAY 20 CORRIDOR IN FAR 
NW IL.

TONIGHT INTO MONDAY...GFS AND UKMET STILL INDICATE SOME LIGHT QPF 
OVER SOUTHERN ZONES WITH WEAK MID LEVEL WAVE AND CVA INDICATED. 
TREND HAS BEEN TO FOR MODELS TO WEAKEN SYSTEM WITH EACH RUN AND HAVE 
TRIMMED BACK SNOW POPS TO CHANCE IN SOUTH. CLOUDS DEVELOPING AHEAD 
OF WAVE TONIGHT WILL PREVENT TEMPS FROM PLUNGING AS LOW AS THIS 
MORNING...DESPITE HIGH MOVING OVERHEAD AND WENT CLOSE TO MAV IN 
SOUTH...WITH NORTH CLOSER TO MET WHERE SKIES WILL START OUT AT LEAST 
PARTLY CLOUDY. HIGH MOVES INTO OHIO RIVER VALLEY MONDAY WITH BACKING 
FLOW DURING DAY. WARM AIR ADVECTION WILL NOT BE REALIZED UNTIL LATE 
DAY AND CLOUD COVER WILL LIMIT HIGHS TO COLDER MAV NUMBERS.

BEYOND...HAVE ALSO TRIMMED BACK PRECIP CHANCES ON THURSDAY AS GFS NOW
CLOSER TO CANADIAN WITH WEAKER NORTHERN STREAM SYSTEM MOVING INTO 
GREAT LAKES. OVERALL...MINOR TWEEKS TO TEMPERATURES WITH LATE WEEK 
WARM UP ON TRACK AS WESTERN UPPER RIDGE MOVES EAST INTO AREA.

.DVN...
IA...WIND CHILL ADVISORY THIS MORNING...NORTH OF INTERSTATE 80.
IL...WIND CHILL ADVISORY THIS MORNING...MAINLY NORTH OF HIGHWAY 30.
MO...NONE.

$$

DLS