[LeArc] Forecast Discussion : MLI@ 8/27/02 2:37:27 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 271942
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
240 PM CDT TUE AUG 27 2002

SHORT RANGE MODELS FAIRLY SIMILAR IN PINCHING OFF UPPER LOW OVER ID
THIS EVENING...WITH FEATURE COMBINING WITH SOUTHERN GRT BSN RIDGE TO
FORM BLOCKING PATTERN THAT WILL MAINTAIN ITSELF AT LEAST THROUGH THE
MID WEEK PERIOD. AVN CONTINUES TO REV UP A WANDERING VORT OUT OF THE
NORTHERN PLAINS AND OVER IA WED NIGHT AND INTO THU...BUT FEEL THIS
FEATURE TO HAVE LITTLE CONSEQUENCE AS UPPER RIDGING HAS ITS DAMPENING
AFFECT...AS WELL AS DRIER AIR INFLUX IN THE LOW TO MID LEVELS FROM
THE EAST AND OVER THE REGION. BROAD UPPER RIDGING TO GET ENHANCED
OVER THE MIDWEST AT WEEKS' END AS GULF OF AK ENERGY DIGS TROUGH INTO
THE PACIFIC NORTHWEST...THUS EXTENDED PERIOD OF DRY WX ON TAP THROUGH
AT LEAST FRI.

LARGE GRT LKS SFC RIDGE TO INFLUENCE LOCAL AREA NEXT 24-36 HRS WITH
FAIR WX AND EAST-NORTHEAST SFC FLOW. THIS USUALLY MEANS COOLING LK MI
EFFECT...BUT FLOW TO BE WEAK FOR LESS OF AN AFFECT ON HIGHS. EVENTUAL
DRYING IN THE FORM OF LOWER DPTS BEING ADVECTED IN WITH THIS
NORTHEAST FETCH...WILL HAVE AN EFFECT ON OVERNIGHT LOWS HOWEVER.
CONCERN FOR TONIGHT IF ANY FOG WIDESPREAD OR DENSE ENOUGH FOR ZONE
MENTION...AND LOW TEMP POTENTIAL. LOOKING AT UPSTREAM DPTS IN
SOUTHERN LOWER MI STILL IN THE LOW TO MID 60S...NO REAL BIG INFLUX OF
DRIER 50 DPT AIR TO BE REALIZED FOR FIRST PERIOD. FEEL LOWS MAY BE
SIMILAR TO LAST NIGHT...MAYBE 1 OR 2 DEGREES COOLER TAKING INTO
ACCOUNT DIURNAL DPT POTENTIAL DROP-OFF. WITH LIGHT EASTERLY SFC FLOW
AND CLEAR SKIES...PATCHY FOG AGAIN A POSSIBILITY...BUT DON'T FEEL AT
AN EXTENT THAT'S ZONE MENTIONABLE. BUT CAN'T RULE OUT PATCHY DENSE
FOG AGAIN ALONG THE IL/WI BORDER EXTENDING TO JUST WEST OF DBQ LATE
TONIGHT...AND WILL PONDER SOME WORDING THERE. BUT THIS AREA ALSO
FIRST IN LINE FOR SOME DRIER AIR FROM THE U.P. OF MI...SO MAY BE A
DRAW.

WITH SOME MIX OUT AND LOWERING OF SFC HUMIDITIES BY NORTHEAST
FETCH...AIRMASS SHOULD WARM INTO MID 80S ON WED. ANOTHER ROUND OF THE
LATE MORNING/AFTERNOON CU BLOSSOM WILL TAKE PLACE...BUT FEEL MAYBE
LESS THAN TODAY SO AS NOT TO RUIN ONGOING MOSTLY SUNNY WORDING. LOWER
DPTS SHOULD LEAD TO BETTER OPPORTUNITY FOR MORE WIDESPREAD LOWS IN
50S FOR THU MORNING.

.LONGER RANGE(FRI-TUE)...GENERAL MEDIUM RANGE MODEL SOLUTION/ENSEMBLE
(ESPECIALLY UKMET/ECMWF) SUGGESTS LARGE UPPER AND LOWER BLOCKING
HIGH COMPLEX OVER THE EASTERN HALF OF THE CONUS TO MAINTAIN
MODERATING BUT DRY WX LOCALLY INTO SAT...AS UPPER JET ENERGY DIGS
TROUGH ACRS NORTHERN ROCKIES AND PLAINS. EURO SUGGESTS SOME OF THIS
UPPER ENERGY TO SPILL ACRS UPPER MIDWEST AND POSSIBLY FIRE SOME
CONVECTION ON SAT...BUT COVERAGE MAY BE BIT SPOTTY FOR MENTION THIS
FAR OUT. ALSO FEEL PRECIP FROM SOUTHEAST UPPER LOW WON'T MAKE IT THIS
FAR NORTHWEST. MODEL DIFFERENCES ARE STILL THERE ON TIMING AND
STRENGTH OF EVENTUAL SFC WAVE/FRONTAL COMPLEX PROPAGATION OVER THE
LOCAL AREA. THIS SYSTEM CONTINUES TO GET HUNG UP IN SOUTHWEST FLOW
ALOFT ON LEE SIDE OF TROUGH OVER MN AND INTO THE CENTRAL PLAINS INTO
SUNDAY...BEFORE APPEARING TO MAKE SOME HEADWAY TO THE EAST. THIS
AGAIN WOULD SUPPORT A DRY SATURDAY AND BETTER CHANCE LATE SUNDAY
AFTERNOON AND SUNDAY NIGHT FOR CONVECTIVE THREAT. WAA PROPERTIES
AHEAD OF THIS INCOMING BOUNDARY MAY MEAN WARMER HIGHS FOR SUNDAY THAN
EVEN THE WARMER MRFS' MID 80S...AND MAY GO ABOVE GUIDANCE. WILL KEEP
LABOR DAY DRY FOR NOW...BUT WILL HAVE TO WATCH FOR BOUNDARY SLOWING
DOWN OR GETTING HUNG UP OVER THE AREA FOR CONTINUED PRECIP THREAT
INTO THE HOLIDAY.


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

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