[LeArc] Forecast Discussion : MLI@ 8/5/02 3:04:45 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 050805
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
304 AM CDT MON AUG 5 2002

PLENTY OF CONVECTION LINED UP EARLY THIS MORNING ALONG WAVY FRONT 
THROUGH NORTHERN IL...IA AND NEB. AS OF 07Z...APPEARED TO BE THREE 
UPSTREAM MCCS THAT WILL IMPACT DVN FORECAST AREA THIS MORNING WITH 
REMNANTS TO IMPACT LATER TODAY. THESE SLOW MOVING COMPLEXES MAINLY 
HEAVY RAIN PRODUCERS AND ARE ALINED ALONG AND NORTH OF STATIONARY 
FRONT FROM NEAR DVN TO NW IA. FORECAST CHALLENGE IS POPS AND HEAVY 
RAIN POTENTIAL TODAY AND TONIGHT AS MID LEVEL WAVES MOVE EAST ALONG 
FRONT AS IT DRIFTS SLOWLY SOUTH.

00Z MODELS SHOWING USUAL DIFFICULTY IN HANDLING OF QPF AND SURFACE 
FRONT LOCATION. AVN HAD DECENT HANDLE ON FEATURES AT 00Z...THEN 
CONVECTIVE FEED BACK FROM WESTERN NEB MCV BLOWS UP OVER NE NEB INTO 
NW IA TOWARD 12Z. MAIN MESSAGE FROM LATEST MODEL RUN AND ANALYSIS IS 
NECESSITY OF EXTENDING OF RAIN CHANCES FROM CURRENT FORECAST THROUGH 
TODAY INTO TONIGHT AS LITTLE CHANGE OCCURS IN UPPER LEVEL FEATURES 
WITH UPPER HIGH JUST TO SOUTH AND HIGH PRECIPITABLE WATER AND LOW 
LEVEL E-W THETA E RIDGE AXIS REMAINING OVER SOUTH. FOLLOWED MODEL 
BLEND...LEANING CLOSEST TO AVN.

NOWCASTING CENTRAL IA WAVE ALONG FRONT WILL REQUIRE CATEGORICAL POPS 
FOR JUST ALONG FRONT IN E CENTRAL IA INTO W CENTRAL IL WITH LIKELY 
FURTHER SOUTH AND NORTH TODAY. UPSTREAM H5 WAVES IN WESTERN IA AND 
NEB WILL MOVE INTO FORECAST AREA THIS AFTERNOON WITH ADDITIONAL 
SUPPORT FROM UPPER DIVERGENCE TO KEEP WIDESPREAD RAIN AND THUNDER 
MAINLY OVER SOUTHERN 2/3RDS THROUGH DAY. WILL INCLUDE MENTION OF 
HEAVY RAINFALL BUT NOT GO AS FAR AS ISSUING A FLOOD WATCH. LOCAL 
AMOUNTS OF 2-3 INCHES OCCURRED LAST NIGHT...BUT SO FAR RAIN HAS BEEN 
LOCALIZED AND WITH RELATIVELY HIGH FFG VALUES WILL LEAVE OUT FOR NOW 
AND LET DAY SHIFT KEEP AN EYE OUT. ALSO...APPEARS LOCAL 88D PRECIP 
ESTIMATES MAY BE ON HIGH SIDE TONIGHT. SURFACE FRONT SHOULD DROP TO 
FAR SOUTH FORECAST AREA BY EVENING...HOWEVER...CONVERGENCE ALONG H85 
FRONT FURTHER NORTH MAY STILL PRODUCE SHOWERS AND FEW THUNDERSTORMS 
OVER MUCH CENTRAL AND SOUTHERN ZONES AND HAVE THUS EXTENDED RAIN 
CHANCES INTO EVENING AND WORDING FOR OVERNIGHT FOR FAR SOUTH. 
SURFACE HIGH MOVING INTO UPPER MI PUSHES FRONT THROUGH AND PROVIDES 
COOLER AIRMASS FOR TUESDAY. CANNOT TOTALLY IGNORE WIDESPREAD QPF 
OVER SE IA WITH H85 FRONT IN VCNTY AND PUT IN ISOLATED MORNING 
SHOWERS...OTHERWISE BECOMING SUNNY AND LESS HUMID. 

LITTLE CHANGES TO FORECAST FROM TUESDAY AFTERNOON AND BEYOND AS 
UPPER FLOW AMPLIFIES WITH RIDGE BUILDING OVER CENTRAL CONUS AND 
TROUGHS ON EAST AND WEST COASTS.          

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

DLS