[LeArc] Forecast Discussion : MLI@ 12/8/02 4:06:37 AM

[Richard R. Sample]

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


FXUS63 KDVN 081020
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
415 AM CST SUN DEC 8 2002

TEMPERATURES MAIN CHALLENGE NEXT SEVERAL DAYS...THEN FOCUS SHIFTS
TO LATE WEEK SYSTEM.

COLD ADVECTION OVERSPREADING REGION IN LAST FEW HOURS WITH TEMPS 
DOWN IN THE TEENS IN PORTIONS OF NORTH AND WEST.
MAIN QUESTION IS HOW MUCH REBOUND ON TEMPS TODAY WITH LOTS OF SUNSHINE
AND JUST SOME CIRRUS ESPECIALLY THIS MORNING...THICKEST IN THE
FAR SOUTH FOR A WHILE. OVERALL SOLAR INSOLATION TO COMBAT MODERATE
COLD ADVECTION AND WILL NUDGE UP TEMPS A BIT ESPECIALLY CENTRAL AND SOUTH.
OVERALL MET GUIDANCE LOOKS REASONABLE...AS MAV GUIDANCE HAS 
EXHIBITED COLD BIAS WITH OUTBREAKS THIS SEASON AND THIS LOOKS LIKE
JUST MODERATE COLD ADVECTION.

TONIGHT...WILL SIDE FEW DEGS BELOW COLDEST GUIDANCE WHICH MESHES WELL
WITH PREVIOUS PACKAGE. CANADIAN SURFACE HIGH PASSES 
OVERHEAD PROVIDING IDEAL RADIATIONAL COOLING WITH MOSTLY CLEAR SKIES
AND LIGHT WINDS...AND GIVEN AMOUNT OF DRY AIR...EXPECT 
SINGLE DIGITS MOST LOCATIONS. THIS IS VERIFYING WELL AT 09Z WITH
STATIONS ACROSS NORTHEAST ND AND SOUTHERN CAN IN CLOSE PROXIMITY TO SURFACE
HIGH RUNNING 0 TO -10 F WITH SOME SNOW COVER. HIGH SHIFTS EAST
LATE TONIGHT SO TEMPS TO LEVEL OFF ESPECIALLY WEST OF THE MISSISSIPPI.

TEMPS INTO MID WEEK CHALLENGING WITH CONTINUED WARM ADVECTION.
H85 TEMPS PROGGED TO CLIMB FROM -9 C AT 00Z MON...TO -2 C BY 00Z TUE AND
+2 C BY 00Z WED. MOST OF WARM AIR TO GO OVER THE TOP BUT WITH
WINDS PICKING UP WEST MON AFTN WENT CLOSER TO MET GUIDANCE IN THESE AREAS.
ELSEWHERE WENT WITH BLEND OF FWC/MAV GUIDANCE.

WARMUP CONTINUES INTO MID-WEEK WITH LLVL SOUTH/SOUTHWEST WINDS...WHILE
DOWNSLOPE COMPONENT DEVELOPS OFF ROCKIES INTO WESTERN IA.
WENT ABOVE MAV GUIDANCE BY FEW DEGS MOST LOCATIONS DURING THIS TIMEFRAME.

EXTENDED

MODELS STILL SHOWING DIFFERENCES (STRENGTH/TIMING/LOCATION) WITH 
LATE WEEK SYSTEM...SO WON/T MAKE ANY CHANGES TO
CURRENT EXTENDED ATTIM. 00Z GFS/AVN LOOKS SUSPECT WITH SOMEWHAT DRY QPF GIVEN
STRENGTH OF CLOSED SYSTEM. SURFACE WINDS IN MODEL LOOK SHAKY WITH
BROAD AREA OF CALM WINDS ALONG TX GULF COAST. ALSO...THERMAL PARAMS
SUGGEST RAIN OR POSSIBLY MIX GOING OVER TO SNOW. BUT THIS IS SEVERAL DAYS
AWAY SO HAVE TIME TO REFINE DETAILS. 

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


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