[LeArc] Forecast Discussion : MLI@ 4/9/2003 1:41:16 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 091839
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
135 PM CDT WED APR 9 2003

.OVERVIEW...AREA NOW IN QUIET NORTHWEST FLOW AS CLOSED UPPER LOW WINDS
UP IN SE CONUS.  SFC RIDGE OVERHEAD AND ANALYSIS SHOWS ONLY VERY SLOW
MIGRATION EAST NEXT 24-36 HOURS.  UPPER AIR ANALYSIS SUPPORTS SATELLITE
OF SUBSIDENCE AND FAIR WEATHER WITH LITTLE OR NO CLOUD COVER.  NEXT
PACIFIC SYSTEM TO SLIDE TO THE NORTH FOR LITTLE EFFECT.  UPPER LOW TO
SLOWLY SLIDE NE IN TYPICAL SPRING FLOW OF DECELERATING JET SO
MODIFICATION MAIN ISSUE NEXT COUPLE DAYS.

...TEMPERATURES FORECAST ISSUE THIS CYCLE AND HOW QUICKLY AIR MODIFIES
THE FORECAST CHALLENGE...

.DIAGNOSIS AND DAYS 1-3...ALL MODELS SUPPORT QUIET WEATHER WITH
PERSISTENCE BEST GUIDE FOR LOWS TONIGHT WITH IDEAL RADIATIONAL COOLING
AND SOME SNOW ALONG HIGHWAY 20 SUGGESTING LOWS ~1-2 CATEGORIES BELOW
COLDEST GUIDANCE.  PATCHY FOG LATE BUT DON'T SEE WIDESPREAD COVERAGE
BASED ON LAST NIGHT AND LIMITED LOW LEVEL MOISTURE.   THEN HIGHS
THURSDAY WILL GO A FEW DEGREES ABOVE MAV BASED ON 18Z TEMPS WITH ETA TOO
WARM AND NGM TOO COLD...BOTH BY 5-8 DEGREES.  SLIGHT RISK OF POPS LATE
SATURDAY BUT LIMITED FORCING/MOISTURE NOT ENOUGH TO WARRANT POPS AT THIS
TIME. THEN SLOWLY SLIDE TEMPS TO MODEL BLEND BY SATURDAY...NICE SPRING
WEATHER TO ENJOY.  WILL KEEP NEAR RECORD LOW VERBIAGE FOR NORTHERN 1/2
OR SO TONIGHT AS LOWS WILL BE WITH A FEW DEGREES OF RECORDS AND DBQ
BROKE THEIR RECORD LOW LAST NIGHT BY 3 DEGREES DUE TO SNOWCOVER.

.EXTENDED (SUN-TUE)...ALL MODELS SHOW QUIET REGIME WITH NEXT CHANCE
OF POPS NOT UNTIL TUESDAY WITH NEXT PACIFIC SYSTEM.  PLAN TO AVERAGE
HIGHS 1+ CATEGORY ABOVE GUIDANCE WITH SW FLOW AND LOWS NEAR FMR/MEX.

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

$$

NICHOLS