[LeArc] Forecast Discussion : MLI@ 8/1/02 3:24:46 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 010825
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
325 AM CDT THU AUG 1 2002

WATER VAPOR LOOP SHOWS STRONG S/W NERN MT AT 06Z WITH POTENT COLD FRONT
LOCATED ACROSS SD AND WARM FRONT EXTENDING EAST ACROSS NORTHERN
MN FROM LOW CENTERED NEAR KFAR. 01/00Z MODELS HAVE COME INTO AGREEMENT
MOVING COLD FRONT SE TO NEAR A KALO/KDSM/KFNB LINE BY 18Z AND ONTO
A KRFD/KMLI/KIRK AROUND 00Z.  THIS TIMING SHOULD GIVE AIRMASS OVER CWA
PLENTY OF TIME TO DESTABILIZE BEFORE FROPA OCCURS.  META SHOWS SBCAPES
AROUND 5000 J/KG BY 18Z OVER ECNTRAL IA...HOWEVER THESE ARE LIKELY
OVERDONE DUE META HIGH SURFACE TEMPS.  HIGH BOUANCY AND GOOD LOW
LEVEL CONVERGENCE ALONG FRONT SHOULD SHOULD BE ENOUGH TO BREAK CAP BY
LATE MORNING EARLY AFTERNOON WITH TSRA DEVELOPING CLOSE TO THE
BOUNDARY AND PROGRESSING SOUTHEAST AHEAD OF FRONT.  LOW LEVEL DELTA
THETA E'S SUGGEST DAMAGING WIND POTENTIAL WITH ANY STORMS THAT
DEVELOP. MODELS...ESPECIALLY THE ETA SUGGESTING THAT POST FRONTAL
SHRA/TSRA LINGERING LONGER THAN PREVIOUSLY EXPECTED SO WILL HOLD ONTO
PCPN CHANCES LONGER IN THE SOUTH.  WILL TRY ONE MORE TIME TO WARM
TEMPS INTO LOWER TO MIDDLE 90S ACROSS THE SOUTH.  PREFRONTAL
COMPRESSION AND SW WINDS ARE FAVORABLE FOR GOOD WARM UP.  COLD FRONT
SHOULD BE SOUTH OF CWA BY 06Z WITH HIGH PRESSURE MOVING EAST ACROSS MN.
INFILTRATION OF COOL CANADIAN AIR WILL DROP TEMPS BACK INTO THE LOWER
TO MIDDLE 60S PER MAV GUIDANCE TONIGHT.

BELOW NORMAL TEMPS EXPECTED FRIDAY WITH EASTERLY FLOW OFF HIGH PRESSURE
OVER CWA.  WILL STAY CLOSE TO COOLER MAV NUMBERS FOR HIGHS
FRIDAY AND LOWS SATURDAY MORNING. LOOKS LIKE RETURN FLOW SETS
UP SATURDAY WITH AVN SUGGESTING A PCPN THREAT IN BROAD WAA ZONE OVER
REGION.  WILL HOLD OFF ON ADDING POPS NOW AND LET DAY SHIFT HAVE ANOTHER
LOOK AT IT.

WILL NOT MAKE ANY CHANGES TO EARLY PART OF EXTENDED YET...BUT MODELS
SHOWING RIDGE STRENGTHENING OVER MISSISSIPPI VALLEY AS TROUGH DIGS OVER
WEST COAST.  FRONT/PCPN ORIGINALLY EXPECTED TO MOVE THROUGH SUNDAY LOOKS
QUESTIONABLE NOW.

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

DLF