[LeArc] Forecast Discussion : MLI@ 9/12/02 1:50:06 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 121856
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
155 PM CDT THU SEP 12 2002

.OVERVIEW...EARLY FALL HIGH PRESSURE LOCATED OVER SOUTHERN GREAT LAKES
MOVING VERY SLOWLY EAST.  UPPER AIR PATTERN SHOWS BROAD AND DIFFUSE
UPPER LOW SPINNING OVER UTAH PRODUCING MODERATE AMOUNTS OF CLOUDS AND
PRECIPITATION INTO CENTRAL HIGH PLAINS WITH SUGGESTION OF MOVING SLOWLY
EAST BASED ON HEIGHT FALL PATTERN. VIGOROUS JET SOUTH OF ALASKA TO ALLOW
STRONGER SHORT WAVE INTO PACIFIC NORTHWEST NEXT COUPLE OF DAYS.

TEMPS AND INCREASING CLOUDS WITH POPS BY SATURDAY NEAR TERM ISSUE AND
THEN COOL DOWN WITH NEXT FRONT FORECAST CONCERNS...

.DIAGNOSIS AND DAYS 1-3...MODELS VERIFY ADEQUATELY WITH ETA BEST OVERALL
WITH DYNAMICS...MOISTURE AND PRECIPITATION FIELDS FOLLOWED CLOSELY BY
AVN. THIS SUGGEST WILL SEE GRADUAL INCREASING HIGH CLOUDS TONIGHT INTO
FRIDAY.  LIGHT WINDS AGAIN TONIGHT BUT CIRRUS SHIELD SHOULD LIMIT AMOUNT
OF COOLING TONIGHT SO WILL TREND CLOSER TO MAV/MET/FWC BLEND.  THEN WITH
FILTERED SUNSHINE MOST AREAS AND LIGHT SOUTHEAST TO SOUTH WINDS...SEE
LITTLE REASON TO DEVIATE MUCH FROM GUIDANCE BLEND BASED ON 18Z OBS
UPSTREAM IN HIGH CLOUD AREAS.  WILL KEEP CHANCE POPS NW 1/3 AREA FOR
FRIDAY NIGHT AS UPPER VORT LOBE SHOULD ALLOW SOME DECAYING LIGHT RAIN OR
SPRINKLES. THEN HIGH CHANCE POPS SATURDAY OR SATURDAY NIGHT DEPENDING ON
LOCATION AS WESTERN VORT ENERGY SLIDES ACROSS AHEAD OF STRONGER UPSTREAM
DIGGING TROUGH.  TIMING AND PHASING ISSUES SHOULD BE BETTER RESOLVED
NEXT 12 TO 24 HOURS TO MORE ACCURATELY ASSESS COVERAGE...TIMING AND
AMOUNTS BUT LIMITED MOISTURE SUGGEST LIGHT OR AT MOST...SOME AREAS OF
MODERATE RAINFALL AMOUNTS WITH THIS DISTURBANCE. INDICATIONS OF FORECAST
COOL DOWN FOR SUNDAY SUGGEST AVN STILL IS A TAD TOO COOL SO WILL STAY
NEAR CURRENT FORECAST TEMPS.

.EXTENDED (MON-THU)...ALL MODELS SUGGEST NICE EARLY AUTUMN WEATHER INTO
TUESDAY WITH WARMUP AND CHANCE OF SHOWERS AND THUNDERSTORMS MID WEEK
WITH NEXT SYSTEM.  SLIGHTLY COOLER ON LOWS THAN FMR/MEX MONDAY BASED
ON IDEAL RADIATIONAL COOLING AND LIGHT WINDS...BUT OTHERWISE CLOSE
TIL TUE PM INTO WED PM AS WAA KICKS IN AHEAD OF LEE SIDE LOW FOR 1-2
CATEGORIES ABOVE MEX/FMR BLEND.

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

NICHOLS