[LeArc] Forecast Discussion : MLI@ 12/9/02 4:31:48 AM

[Richard R. Sample]

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


FXUS63 KDVN 091045
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
415 AM CST MON DEC 9 2002

CONCERNS INCLUDE EXTENT OF WARMUP NEXT FEW DAYS ALONG WITH 
POTENTIAL FOR STRATUS AND/OR FOG AHEAD OF LEE SIDE TROUGH...THEN PCPN CHCS 
LATE WEEK. 

COLD SURFACE HIGH SHIFTING EAST OF THE AREA EARLY THIS MORNING WITH
RETURN FLOW DEVELOPING WESTERN ZONES ATTIM.
TEMPS BENEATH HIGH DROPPED WELL INTO SINGLE DIGITS BUT ARE NOW ON THE
RISE WITH WARM ADVECTION...AND ANTICIPATE NICE DIURNAL SWING
ON ORDER OF 25 TO 30 DEGS UNDER PARTLY TO MOSTLY SUNNY SKIES.

TONIGHT...EXPECT MOSTLY CLEAR SKIES AND WITH WEAK PRESSURE GRADIENT
RESULTING IN LIGHT BOUNDARY LAYER WINDS WILL SIDE
TOWARD COOLER END OF GUIDANCE. BASED ON POSITION WRT BACKSIDE OF COLD HIGH
OUR TEMPS SHOULD RESEMBLE THOSE CURRENTLY IN SOUTHEAST SD
NORTHWEST IA AND NORTHEAST NE WHERE TEMPS RUNNING UPPER TEENS TO L20S.
NEXT CONCERN THEN IS LARGE AREA OF STRATUS AND FOG OVER WHAT/S 
LEFT OF SNOWCOVER IN SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY. 
STRATUS WILL BE ON THE MOVE NORTHWARD AHEAD OF LEE SIDE TROUGH...BUT WITH
LLVL FLOW STILL FAIRLY LIGHT EXPECTING IT TO STAY SOUTH OF CWA...SO
WILL CONTINUE MOCLEAR. EXPECT SOME MOISTENING OF BOUNDARY LAYER THUS LIGHT
AVIATION FOG POSSIBLE. 

WARM ADVECTION CONTINUES INTO WED WITH FURTHER WARMING. BIG CONCERN WILL BE
WITH POTENTIAL STRATUS/FOG AND IMPLICATIONS ON TEMPS TUE NIGHT-WED.
IF SHOULD DEVELOP THEN GOING TEMPS MAY BE A BIT OPTIMISTIC FOR WEDS. ALSO
MINS TUE NIGHT WOULD MOST LIKELY BE A TAD TOO COOL. 
A LITTLE BETTER LLVL WIND PROGGED TUE NIGHT-WED TO SUPPORT FURTHER INCREASE IN
BOUNDARY LAYER MOISTURE. FOR NOW WILL GO WITH PARTLY CLOUDY...BUT
WILL NEED TO MONITOR IN LATER SHIFTS FOR MORE PESSIMISTIC SKY WORDING 
WHICH IN TURN WOULD MEAN TRIMMING BACK MAXES SOME AND INCLUDING MENTION OF FOG
AND POSSIBLY EVEN -DZ. THIS COULD LINGER THROUGH THURS AS WELL. 

EXTENDED

STILL DIFFERENCES EXIST WITH MODELS HANDLING OF CLOSED UPPER LOW LATE
WEEK AND EARLY WEEKEND. SYSTEM ABOUT 30M DEEPER WITH 06Z RUN
OF GFS. COLD AIR LACKING WITH THIS SYSTEM...THUS PCPN TYPE APPEARS TO BE
MAINLY RAIN OR RAIN/SNOW MIX. OVERALL WON/T MESS WITH TIMING 
DUE TO UNCERTAINTY BUT IF TREND OF DEEPENING CONTINUES THEN LIKELY TO SEE 
PCPN HOLD OFF UNTIL FRI-SAT TIMEFRAME.


IA...NONE.
IL...NONE.
MO...NONE.


M^2