[LeArc] Forecast Discussion : MLI@ 4/7/2003 5:00:41 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 070957
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
457 AM CDT MON APR 7 2003

THERE IS AN OLD ADAGE THAT SAYS BEWARE OF EASTERLY FLOW. SUCH WAS
THE CASE WITH THIS SYSTEM. FIRST...IT TOOK LONGER TO SATURATE THE
LOWER LEVELS WHICH CUT DOWN OF THE SNOW AMOUNTS. SECOND...FOR ONCE
THE AVN WAS CORRECT WITH ITS MUCH FARTHER NORTH SOLUTION THAN THE
UKMET...WHICH NORMALLY IS MORE SKILLFUL THAN THE AVN. LASTLY...WE
ARE IN MODERATE TO SEVERE DROUGHT AND NATURE OBVIOUSLY WANTS TO
CONTINUE THAT TREND.

NONETHELESS ALL WARNINGS HAVE BEEN DOWNGRADED TO ADVISORIES. FIRST
LOW AROUND KSTJ HAS OCCLUDED WITH A NEW LOW DEVELOPING AROUND KPAH.
UKMET WAS CORRECT WITH THIS PROCESS OCCURRING BUT WAS TOO FAR SOUTH.
OCCLUDED LOW WILL DRIFT EAST ACROSS NORTHERN MISSOURI BEFORE
DISSIPATING INTO A TROF. PER 03Z AND 06Z RUC...PRECIP BEGINS WHEN
CONDENSATION PRESSURE DEFICITS GO TO 20 MB OR LESS AND ENDS WHEN
DEFICITS RISE TO 20 TO 40 MB. FOLLOWING THIS IDEA PRECIP TO END THIS
MORNING OVER ABOUT THE SOUTHERN THIRD OR SO WHILE CONTINUING UP
NORTH. PTYPE ALSO TRICKY. PRECIP REMAINS ALL SNOW WHERE SURFACE WBZ
IS 32 DEGREES OR LESS...ABOVE THAT A MIX OCCURS. DEFORMATION ZONE TO
BE JUST NORTH OF CWFA SO HEAVY SNOW ACROSS THE NORTH SHOULD SHUT DOWN
BY MID MORNING TO ONLY LIGHT SNOW. NOW ONLY EXPECT A COUPLE MORE
INCHES UP NORTH AND WITH PRESSURE GRADIENT STARTING TO RELAX...
BLOWING AND DRIFTING TO BECOME LESS OF A THREAT DUE TO THE WET NATURE
OF THE SNOW.

WRAP AROUND PRECIP TO OVERSPREAD CWFA TONIGHT AND CONTINUE TUESDAY
MORNING BEFORE ENDING. CLEARING TO OCCUR DURING THE AFTERNOON.
HOWEVER WITH BRISK NORTHEAST FLOW OFF THE LAKES...WOULD NOT BE
SURPRISED IF CLOUDS LINGER LONGER. ALL MODELS ARE NOW SLOWER WITH
SURFACE RIDGE BUILDING NOT BUILDING IN UNTIL THURSDAY. THIS WOULD
HELP KEEP TEMPERATURES DOWN AS WAA DOES NOT START UNTIL LATE
THURSDAY.

DID NOT PLAY WITH THE EXTENDED DUE TO TIME CONSTRAINTS.

.DVN...WINTER WEATHER ADVISORY THIS MORNING
IA...IAZ040>042-051>-054-063>068-076>078
IL...ILZ001-002-007-009-015>018-024
MO...NONE

$$

SF