[LeArc] Forecast Discussion : MLI@ 1/14/03 4:08:29 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 142214
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
414 PM CST TUE JAN 14 2003

FIRST SIGNIFICANT WX EVENT TO AFFECT THE AREA IN QUITE SOME TIME
EXPECTED LATE WED NIGHT INTO THURS MORNING. UNTIL THEN RIDGE TO MOVE
ACROSS THE AREA AND ALLOWING TEMPERATURES TO PLUMMET TONIGHT...
ESPECIALLY OVER THE SNOW FIELD IN THE CWFA. WINDS TO REMAIN UP
SOMEWHAT TONIGHT WHICH WILL HELP TEMPS FROM GETTING TOO FAR OUT OF
LINE.

CLIPPER TYPE HYBRID SYSTEM TO SIDE SWIPE THE CWFA WED NIGHT/THURS.
CURRENT THINKING IS 20 TO 1 RATIOS BUT WOULD NOT BE SURPRISED IF
THEY TURN OUT TO BE 25 TO 1. MODELS TRENDED FURTHER NORTH IN TIME AS
WELL (NO SURPRISE). BASED ON RATIOS SHOULD SEE A 1 TO 3 SWATH FROM
ABOUT HIGHWAY 30 TO HIGHWAY 34...AND 3 TO 5 HIGHWAY 34 ON SOUTH.
CONDENSATION PRESSURE DEFICITS/FORECAST SOUNDINGS INDICATE SNOW TO
BEGIN AFTER MIDNIGHT AND LIKELY TO BE DONE AROUND 15Z THURSDAY.
THUS A QUICK 7-8 HOUR SNOW EVENT. FRESH SNOW FIELD TO ALLOW TEMPS TO
GO BELOW GUIDANCE THURSDAY NIGHT.

EXTENDED WISE...WEAK SYSTEM TO MOVE THROUGH ON SATURDAY. NEW AVN
HAS MORE QPF THAN 00Z RUN BUT FORCING NOT ALL THAT GREAT. THEREFORE
WILL KEEP FLURRIES GOING. SUN/MON CWFA TO SEE 1 OR 2 SYSTEMS TO
SWEEP THROUGH BRINGING A CHANCE OF ADDITIONAL SNOW. DEEP CYCLONIC
FLOW AND CAA ON TUE. COULD SEE SOME --SN BUT HAVE LEFT OUT FOR NOW.
ENSEMBLE MEMBERS TAKE THE AO INDEX NEGATIVE IN THE EXTENDED WITH
DISAGREEMENT ON HOW STRONGLY NEGATIVE IT WILL GO. OVERALL RESULT IS
THAT COLD AIR WILL DUMP INTO THE AREA FROM THE POLE.

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

SF