[LeArc] Forecast Discussion : MLI@ 9/18/02 2:29:32 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 180736
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
236 AM CDT WED SEP 18 2002

SYNOPTIC PICTURE THIS MORNING SHOWS COLD FRONT FROM CENTRAL DAKOTAS
INTO THE TX PANHANDLE.  AT 500H A PRONOUNCED SHORT WAVE IS LIFTING
THROUGH THE FORECAST AREA...TRIGGERING PRECIP ACROSS NORTH CENTRAL
ILLINOIS.  DRY AIR AT MID LEVELS IS INHIBITING PRECIP IN OUR AREA.
A LINE OF PRECIP FROM EASTERN SD TO OMA HAS FIRED IN THE PAST FEW
HOURS ALONG A PSEUDO WARM FRONT.

THE PRIMARY FORECAST CONCERN THIS PACKAGE IS IN FIRST 48 HOURS WITH
VARIOUS CHANCES OF PRECIP...POSSIBLE HEAVY LATE TONIGHT AND THURSDAY.
ALSO OF IMPORTANCE IS COOL DOWN FRIDAY THROUGH THE WEEKEND.

MODELS INITIALIZED WELL AT 00Z ON THE PLAINS COLD FRONT. THE AVN AND
ETA HAD BEST HANDLE ON PRECIP 00Z-06Z.

SHORT-RANGE MODELS AGREE ON LIFTING SHORT WAVE NORTH OF THE AREA BY
SUNRISE. THE COLD FRONT MOVES THRU IN TWO PUNCHES...WITH THE FIRST
PUNCH THURSDAY NIGHT AND THE SECOND FRIDAY NIGHT.  A SURFACE WAVE LIFTS
NORTH ALONG THE FRONT EITHER THURSDAY OR THURSDAY NIGHT...WITH THE AVN
PICKING THE FIRST TIME AND THE ETA THE SECOND.  THE 500H TROF ALSO
MOVES THRU THE AREA IN TWO WAVES...WITH THE FIRST FRIDAY AFTERNOON AND
THE SECOND SATURDAY EVENING.  VV'S ARE STRONG ON-AND-OFF THRU
THURSDAY...WITH UPPER SUPPORT THURSDAY AS A 115 KT JET MOVES OVER.
FIRST PUNCH OF COOLER AIR WILL BE THURSDAY NIGHT AND FRIDAY...WITH
SECOND PUNCH LATE FRIDAY NIGHT AND SATURDAY.

WILL STAY CLOSE TO CURRENT FORECAST. MAY UP POPS A BIT FOR TODAY...AS
ISENTROPIC LIFT SATURATES THE COLUMN.  WILL KEEP HIGH POPS FOR TONIGHT
AND THURSDAY...AND RAISE A NOTCH THURSDAY NIGHT AS UPPER JET SUPPORT
WILL BE IN PLAY.  TEMPS ARE ON TRACK INITIALLY...BUT WILL HAVE TO
RAISE FOR THURSDAY...DUE TO SLOWING OF COLD FRONT.

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

REA