[LeArc] Forecast Discussion : MLI@ 12/11/02 12:59:40 AM

[Richard R. Sample]

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


FXUS63 KDVN 110714
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
110 AM CST WED DEC 11 2002

.OVERVIEW...TYPICAL EL NINO PATTERN WITH STRONG SOUTHERN JET ACROSS
CONUS WITH NEXT SYSTEM ENTERING PACIFIC NORTHWEST.  LOCAL AREA IS
BETWEEN JETS WITH QUIET WEATHER.  SHALLOW TONGUE OF LOW CLOUDS AND
FOG NOW STREAMING NORTH AHEAD OF WEAK LEE SIDE TROUGH INTO WESTERN
1/2 OF IOWA. LITTLE FORCING NOTED TO SUPPORT EASTWARD PROGRESSION OF
LOW CLOUDS AND FOG NEAR TERM.  HEIGHT FALLS FROM PACIFIC SYSTEM
SUGGEST LOW CLOUDS SHOULD SLOWLY MOVE IN NEXT 12-24 HOURS AHEAD OF
THIS ADVANCING SYSTEM.

.DIAGNOSIS AND DAYS 1-3...ETA HANDLING LOW CLOUDS BEST NEAR TERM AT
06Z AND USED AS PRIMARY GUIDANCE NEXT 24 HOURS.  THIS SUGGEST SOME
CLOUDS TODAY FAR WEST...PER NOWCAST TOOLS OF AWIPS DISTANCE TIME
TREND OF CLOUD LINE TO NEAR I-380 CORRIDOR.  USING YESTERDAY AS
BASELINE...CLOUDS TO PARTIALLY CLEAR DURING DAY AND THEN REFORM
AND/OR OVERSPREAD MOST OF REMAINING AREA TONIGHT.  LITTLE FORCING AND
LIMITED DEPTH OF THIS MOISTURE AND STABLE BL PROFILE SUPPORTS AT BEST
SOME AREAS OF DRIZZLE POSSIBLE LATE TONIGHT WITH PATCHY FREEZING
DRIZZLE ALONG AND NORTH OF HIGHWAY 34 INTO EARLY THURSDAY.  WILL THEN
MENTION CHANCE OF RAIN AND SNOW AS BL TEMPS SUPPORT MIXTURE WITH WEAK
TO MODERATE INTENSITY...ESPECIALLY APPLICABLE FOR SOUTHERN 1/2 AREA
THURSDAY NIGHT INTO FRIDAY AS UPPER LOW DIVES SOUTH OF AREA WITH
LIMITED FORCING AND MOISTURE SUPPORTING ONLY CHANCE POPS FOR NOW
USING A BLEND OF UKMET AND AVN WITH ENOUGH POOLING OF LOW LEVEL WINDS
AND UPPER TROUGH KEY JUSTIFICATION TO RATIONALE...AS USUAL...ETA IS
TOO DRY THIS FAR OUT AND NOT USED. TEMPS WILL TEND TO STAY NEAR TO
SLIGHTLY ABOVE GUIDANCE BLEND DEPENDING ON CLOUDS.

.EXTENDED (SAT-TUE)...UKMET ODD MODEL OUT WITH GFS/ECMWF SUGGESTING
ZONAL FLOW WITH NEXT PACIFIC SYSTEM TO USHER IN MILD TEMPS BY SUNDAY
AHEAD OF THIS SYSTEM WHILE UKMET SHOWING INTRUSION OF COLDER AIR
FROM CANADA.  WILL FOLLOW PAST RUNS AND ALSO MODEL CONSENSUS TO ALLOW
TEMPS TO REMAIN MILD OR ABOVE NORMAL INTO MIDDLE NEXT WEEK WITH
ZONAL SOLUTION FROM PACIFIC.

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

NICHOLS