[LeArc] Forecast Discussion : MLI@ 4/13/2003 4:47:42 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 130945
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
435 AM CDT SUN APR 13 2003

SHOULD SEE BIT OF A REBOUND IN TEMPS TODAY FROM SATURDAY...ALTHOUGH
SOUTHEAST SFC FETCH BACK FROM SOUTHERN GRT LKS SFC RIDGE NOT TO TAP
INTO THE WARMEST OF AIRMASSES.  STILL LATE AFTERNOON SOUTH-SOUTHEAST
WIND...DRY SFC DPTS/LOW TO MID LAYERS...AND ANOTHER SUNNY DAY TO MAKE
FOR A CATEGORICALLY WARMER ONE THAN YESTERDAY. TOOK BLEND OF FWC AND
WARMER MET TEMPS...WHICH LOOK GOOD TAKING INTO ACCOUNT UPSTREAM
AIRMASS SOURCE(EAST CENTRAL MO/SOUTHWESTERN IL) AND MODIFICATION.

SFC SYSTEM IN NORTHERN STREAM(MAIN STORM TRACK ALONG NORTHERN
PERIPHERY OF UPPER RIDGE) WILL PUSH ACRS FAR NORTHERN MN/CANADIAN
BORDER OVERNIGHT...INDUCING ENOUGH OF A PRESSURE GRADIENT FURTHER TO
THE SOUTH OVER THE LOCAL AREA TO KEEP ENOUGH OF A SOUTHERLY BREEZE
GOING THROUGH MON MORNING TO PREVENT MONDAY MORNING LOWS FROM
DROPPING BELOW THE 50S IN MOST LOCATIONS.

ROBUST WARM UP STILL LOOKS TO BE ON TAP FOR MONDAY...WITH 45 KT H85
FLOW SHOOTING UP ACRS THE AREA FROM THE SOUTHWEST. SHORT RANGE
MODELS SUGGEST THIS FLOW TO BECOME PARALLEL TO WARMEST THERMAL POOL
FURTHER WEST OVER THE PLAINS AND NOT REALLY ADVECT BEST WARM PUNCH
INTO THE AREA. BUT WITH TIGHTENING SFC GRADIENT AND GOOD MIXING...
LLVL WIND MOMENTUM WILL TRANSFER TO SFC FOR WINDY DAY...AND A WARM
ONE. EVEN IF BEST MIXING OF WARMER THERMAL PROFILE REMAINS JUST TO
THE WEST...COMBINATION OF MIXING OF WARMER AIR WE WILL HAVE AND SFC
WAA BY BRISK SOUTHERLY FLOW...STILL SHOULD BOOST TEMPS INTO THE LOW
TO MID 80S....WITH SOME UPPER 80S NOT OUT OF THE QUESTION ACRS THE
WEST. THIS IS ALL RECORD TERRITORY...WITH MOST SITES HOLDING CURRENT
RECORDS IN LOWER 80S(EXCEPT CID WITH A 86 SET BACK IN 1896).

UPPER DIFFLUENCE AND VORT ENERGY TO SPREAD ACRS THE AREA FROM THE
SOUTHWEST BY TUE AFTERNOON...AS BIG PIECE OF ENERGY FROM WESTERN
CONUS TROUGH PROPAGATES EAST ACRS THE CENTRAL ROCKIES. THIS SHOULD
BRING ABOUT SHOWER AND THUNDERSTORM CHANCE FOR LATER TUE AND
ESPECIALLY TUE NIGHT. LARGE CANADIAN HIGH TO PUSH DOWN ACRS THE
UPPER MIDWEST AND NORTHERN GRT LKS...PUTTING SQUEEZE PLAY ON UPPER
AND SFC LOWS OVER THE AREA. AS SFC HIGH WINS OUT WITH DENSITY
MOMENTUM...WEDNESDAY LOOKING MORE AND MORE LIKE COOLER AND BREEZY DAY
AS BRISK NORTHEAST FLOW OFF LK MI SWEEPS IN. THUS HAVE CHANGED
WORDING TO MORE OF OVER-RUNNING RAIN OVER THIS LLVL FETCH...ALTHOUGH
BOUNDARY ACRS THE FAR SOUTH STILL SUPPORTS SHOWER AND THUNDERSTORMS
FOR A GOOD PART OF THE DAY. HAVE TRIMMED BACK ON WED HIGHS TAKING
INTO ACCOUNT THIS STRONGER NORTHEAST FETCH...AND DAY SHIFT WILL
HAVE TO ASSESS A FURTHER DOWNGRADE. COULD BE BIG TEMP GRADIENT FROM
NORTHEAST TO SOUTHWEST AND SOUTH...IF SFC WAVE HAS SOME POWER TO KEEP
BOUNDARY HANGING ON FOR SOME TIME ACRS THE SOUTHERN CWA.


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

$$

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