[LeArc] Forecast Discussion : MLI@ 8/28/02 1:17:27 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 281822
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
120 PM CDT WED AUG 28 2002

HIGH PRESSURE AT THE SURFACE AND ALOFT REMAINS FIRMLY ENTRENCHED 
OVER THE CENTRAL U.S.  THE AREA OF STRATUS WHICH DEVELOPED FROM 
MOISTURE ADVECTED VIA LAKE MICHIGAN THIS MORNING IS GRADUALLY 
BREAKING UP INTO SCATTERED-BROKEN CU.

MAIN FORECAST CONCERNS ARE NOCTURNAL FOG/STRATUS POTENTIAL THE NEXT 
TWO DAYS THEN PRECIP CHANCES FROM THE WEEKEND INTO NEXT WEEK.

IN THE SHORT TERM...MODELS AGREE IN ADVECTING DRIER LOW-LEVEL AIR 
INTO THE CWA WHICH SHOULD DECREASE THE STRATUS THREAT TONIGHT... 
THOUGH CONFIDENCE HERE IS LOW ESPECIALLY FOR THE NORTHERN PART OF 
THE CWA.  AT ANY RATE...SUFFICIENT BOUNDARY LAYER MOISTURE...MOIST 
GROUND...LIGHT WINDS...LOW DEW POINT DEPRESSIONS AND DRY AIR ABOVE 
850MB PROGGED FOR TONIGHT ALL SUPPORT THE FORMATION OF FOG WHICH 
COULD BE LOCALLY DENSE.  LITTLE CHANGE IN THE PATTERN IS INDICATED 
INTO THE WEEKEND THOUGH WE SHOULD TEND TOWARD A GRADUAL DRYING OF 
THE BOUNDARY LAYER.  THUS PERSISTENCE GENERALLY LOOKS GOOD THE NEXT 
FEW DAYS WITH THE DEPTH/EXTENT OF FOG/STRATUS BEING THE MAIN FACTOR 
AFFECTING TEMPS AS WE WILL SEE WITH TODAY'S MAX TEMPS.

IN THE EXTENDED...THE TROUGH IN THE PACIFIC NORTHWEST STARTS TO 
BREAK DOWN THE RIDGE OVER THE UPPER MIDWEST.  HOWEVER...THE 
STRONGEST FLOW AND DYNAMICS REMAIN TO OUR NORTH.  ALSO THE EASTWARD 
PROGRESS OF THE SURFACE FRONT HAS BEEN SLOWED IN THE LATEST EXTENDED 
MODEL RUNS.  WEAK WARM ADVECTION SUNDAY AND THE PROXIMITY OF THE 
BOUNDARY IS ENOUGH TO WARRANT KEEPING THE POPS ON SUNDAY...BUT A 
LACK OF A GOOD FOCUS SUGGESTS LEAVING POPS OUT OF LATER PERIODS... 
AT LEAST UNTIL SUBSEQUENT MODEL RUNS INDICATE SOMETHING WITH MORE 
CLARITY WHICH COULD SUPPORT PRECIP DEVELOPMENT.

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

WOLF