[LeArc] Forecast Discussion : MLI@ 2/25/03 3:22:27 AM

Tue, 25 Feb 2003 03:22:27 -0600

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

FXUS63 KDVN 250930
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
330 AM CST TUE FEB 25 2003

WHAT WAS THOUGHT TO BE A QUIET PACKAGE IS NOT THE CASE. WEAK
SHORTWAVE TO MOVE THROUGH THE AREA THIS AFTERNOON EVENING. THIS
WILL COMBINE WITH WEAK CHANNELED VORTICITY AND INCREASE LIFT ACROSS
SOUTHERN IOWA INTO ILLINOIS. ALL MODELS SHOW THIS AND RESPOND WITH
THE FOLLOWING SIGNALS...CONDENSATION PRESSURE DEFICITS COLLAPSE...
FRONTOGENETICAL FORCING INCREASES...AND OMEGA INCREASES. GREATEST
LIFT APPEARS IN THE 650-600 MB LAYER WITH TEMPERATURES NOT QUITE
FAVORABLE FOR DENDRITIC CRYSTAL GROWTH. NET RESULT SHOULD BE A
MESOSCALE AREA OF -SN TO DEVELOP LATE THIS AFTERNOON AND CONTINUE
INTO THE EVENING ACROSS SOUTHERN THIRD OF CWFA. GIVEN RAIN/SNOW
RATIOS OF 30 TO 1 OR BETTER THERE SHOULD BE SOME MINOR
ACCUMULATIONS. WOULD NOT BE SURPRISED TO SEE A NARROW BAND OF 1 INCH
ACCUMULATION. THIS WILL HAVE TO BE CLOSELY MONITORED AS POPS COULD
END UP BEING IN THE LIKELY CATEGORY. CONS AGAINST THIS IS A NARROW
SUB CLOUD LAYER THAT IS QUITE DRY ON FORECAST SOUNDINGS AND LIMITED
MOISTURE. HOWEVER BELIEVE OTHER FACTORS WILL OVERCOME THIS. INDEED
THE NEW 06Z META IS GENERATING QPF...ALBEIT TOO FAR NORTH IN IOWA
AND ILLINOIS.

LIFT/FORCING MOVES RAPIDLY EAST BY MIDNIGHT SO SHOULD SEE QUICK END
TO PRECIP. AFTER THAT QUIET WEATHER UNTIL THE WEEKEND. BASED ON
GLOBAL MODELS HAVE PULLED PRECIP IN THE SOUTH ON WEDNESDAY. OTHER
THAN THAT NO CHANGES TO EXTENDED.

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

$$

SF