[LeArc] Forecast Discussion : MLI@ 10/2/02 1:42:01 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 021849
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
125 PM CDT WED OCT 2 2002

FROM DUST TO DELUGE. ROUND 1 OF HEAVY RAIN HAS COME AND GONE...DEPOSITING
WIDESPREAD 1 TO 3 INCHES NORTH HALF WITH SOME HIGHER AMOUNTS
(3.81 INCHES IN OXFORD JUNCTION THROUGH 11:00 A.M.) BUT NO FLOODING PROBLEMS.
NEXT ROUND OF POTENTIALLY HEAVY RAIN SLATED TONIGHT INTO THU...MAINLY IN
THE SOUTH...THEN MAIN FOCUS SHIFTS TO EJECTING UPPER TROUGH 
THROUGH PLAINS AND MIDWEST AND PHASING WITH REMNANTS OF LILI AND POTENTIAL
SIGNIFICANT RAINFALL LATE THU THROUGH FRI.  

AVN FAVORED THIS FORECAST CYCLE...AS ETA APPEARS TO DAMPEN LILI TOO 
QUICKLY UPON REACHING COAST. AVN TRENDING A BIT SLOWER FROM 06Z RUN WITH
EJECTING TROUGH INTO MIDWEST LATE THU-FRI...AND THIS SEEMS MORE
PLAUSIBLE GIVEN LILI NOW CAT 3 MAJOR HURRICANE. THUS CONCERN IS THAT 
SLOWER MOVEMENT OF UPPER TROUGH WOULD ALLOW MORE TIME FOR REMNANTS OF LILI
TO BE PULLED FURTHER NORTH/WEST...PHASING WITH TROUGH 
FURTHER ENHANCING RAINFALL AMOUNTS. 

12Z UPPER AIR ANALYSIS SHOWS BROAD SOUTHWEST UPPER FLOW WITH SEVERAL RIPPLES
EMBEDDED WITHIN. LATEST SURFACE ANALYSIS PLACES FRONTAL ZONE
FROM NORTHWEST MO TO WEAK WAVE NORTH OF CHILLICOTHE MO THEN NORTHEAST TO
SOUTH OF CHI. ISENTROPIC ASCENT OVER FRONTAL ZONE TRIGGERING
NUMEROUS SHOWERS AND THUNDERSTORMS FROM NORTHEAST KS INTO NORTHERN/CENTRAL MO.
 
TONIGHT...HEAVIEST QPF LOOKS TO FOCUS IN THE SOUTH AND PERHAPS EVEN JUST OUT
OF CWA ALONG AND SOUTH OF FRONTAL ZONE. THIS REGION DID NOT RECEIVE
NEARLY AS MUCH RAIN IN THE PAST 24 HRS...AND GIVEN LACK OF PROBLEMS IN NORTH
WITH RECENT HEAVY RAINS...NO HEADLINES NEEDED. WILL CONTINUE WITH
MID SHIFTS THINKING IN PLACING HIGHEST POPS SOUTH. ISENTROPIC LIFT TO CONTINUE
OVER FRONTAL ZONE IN MORE STABLE AIRMASS NORTH HALF...SO BASICALLY PERIODS 
OF LIGHT RAIN OR DRIZZLE WITH LIGHT QPF. AREAS OF FOG EXPECTED...LOCALLY DENSE.
CLOUDS TO LIMIT COOLING. 
 
FRONTAL ZONE BEGINS TO RETURN NORTH AS WARM FRONT LATE THU-THU NIGHT...WITH
INCREASE IN POPS. TEMPS QUITE COOL ON THU WITH FRONT SOUTH
AND CLOUDS AND LLVL E/NE WIND. LEANING TOWARD BLEND OF COOLER MAV/FWC GUIDANCE
AND WILL BE LOWERING CURRENT FORECAST MAXES. 
CATEGORICAL POPS THU NIGHT-FRI WITH MAJOR UPPER WAVE AND LLVL MOISTURE 
SUPPORTIVE OF HEAVY RAINFALL EVENT...WITH REMNANTS/MOISTURE OF LILI WILD CARD
IN REGARDS TO JUST HOW MUCH RAINFALL. WILL RE-ISSUE ESF (FLOOD POTENTIAL
OUTLOOK) WITH AFTERNOON FORECAST. SOME UNCERTAINTIES WITH HOW MUCH RAIN FALLS
PRIOR TO THU NIGHT. HOWEVER...SOILS SATURATED NORTH...SO LIKELY GOING
TO NEED HYDRO HEADLINES NEXT SHIFT.   

DRYING SATURDAY AND COOL WITH NEXT SYSTEM IN NORTHWEST UPPER FLOW SLATED
ON SUN WITH CHANCE PCPN. 

EXTENDED (SUN-WED)...
INITIAL CONCERN IS WITH LOW TEMPS AND FROST/FREEZE POTENTIAL MON MORNING WITH 
RIDGE AXIS BUILDING IN. TIMING OF CLEARING TO HAVE BIG IMPACT.
MODELS SUGGEST LINGERING LLVL RELH SUNDAY EVE REPLACED BY GRADUAL DRYING
OVERNIGHT THROUGH 12Z MON. WILL BE NUDGING CURRENT MINS 
UP JUST A FEW DEGS WHICH WILL STILL BE COUPLE CATEGORIES BELOW MEX GUIDANCE.
NEXT FRONTAL ZONE LOOKS TO APPROACH ON TUE...BUT MOISTURE LACKING WITH
SURFACE RIDGING INTO GULF OF MEXICO. THIS COUPLED WITH
LACK OF COHERENT TRIGGER/FORCING WILL RESULT IN CONTINUATION OF DRY FORECAST
ATTIM. MEX GUIDANCE GENERALLY FAVORED MAKING ADJUSTMENTS AS NEEDED.

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

MCCLURE