[LeArc] Forecast Discussion : MLI@ 6/13/2003 4:49:33 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 130946
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
435 AM CDT FRI JUN 13 2003

SHOWERS PIVOTING NORTH-NORTHWEST AROUND UPPER LOW/VORT ACRS THE
SOUTHERN THIRD OF THE CWA WILL HAVE TO BE DEALT WITH THROUGH AT LEAST
MID MORNING...BEFORE FEATURE SHIFTS TO THE SOUTHEAST. WILL LEAVE OUT
STORM WORDING FOR NOW...ALTHOUGH CAN'T RULE OUT RUMBLE OF THUNDER
IN THOSE AREAS. NORTH TO NORTHEAST FLOW UP TO H8 MB TO TRY AND
ADVECT LAKE ENHANCED STRATUS TOWARD THE CWA AGAIN THROUGH MIDDAY...
BUT UPSTREAM AREAL COVERAGE AND POTENTIAL FOR FORMATION INTO THE
LOCAL AREA OF CONCERN NOT AS IMPRESSIVE AT THIS POINT AS PREVIOUS
NIGHTS. SHORT RANGE MODELS SUGGEST THAT NORTHERLY H85 FLOW WILL
ALSO TRY AND BRING HIGHER H85-H7 LMRHS DOWN FROM WI AS DAY
PROGRESSES...BUT FEEL THIS DECK TO ERODE AS IT TRIES TO MAKE HEADWAY
SOUTH INTO SUBSIDENCE. ANYWAY...ENOUGH ONGOING MID DECK AND CI OVER
THE CWA OFF MO ACTIVITY...AND WITH LLVL STRATUS POTENTIAL...TO
WARRANT MOSTLY CLOUDY MORNING WORDING.

AS DAY PROGRESSES...MUCH OF CWA SHOULD BREAK OUT TO PARTLY TO
MOSTLY SUNNY. FCST SOUNDINGS SUGGEST ENOUGH LINGERING LLVL MOISTURE
COMBINED WITH ADEQUATE HEATING WITH SOME EVENTUAL INSOLATION...TO
MAKE FOR A RATHER UNSTABLE LOW TO MID LEVEL COLUMN BY THIS AFTERNOON.
W/V IMAGERY INDICATING NORTHERN STREAM WAVE OVER EASTERN ND AND
WESTERN ONTARIO ATTM. BULK OF THIS FEATURE WILL LOOK TO SHEAR DOWN
ACRS MN AND WI...BUT COULD HAVE ENOUGH TRAILING LOBE IMPACT TO SET
OFF SOME ISOLATED TO WIDELY SCATTERED CONVECTION FROM MIDDAY ON.
UKMET AND AVN SUGGEST THIS...WHILE ETA/META DRY THIS AFTERNOON
BANKING ON DEEP COLUMN SUBSIDENCE BEHIND EXITING WAVE THATS CURRENTLY
OVER MO. FCST SOUNDINGS DO SUGGEST DECENT CAPPING INVERSION
DEVELOPING AROUND H65 MB AS AFTERNOON PROGRESSES...BUT AT AROUND 18Z
CAP IS STILL WEAK AND CONVECTIVE TEMPS ARE IN THE UPPER 70S. WITH
SOME SUNSHINE...MOST OF THE CWA SHOULD REACH AT LEAST THE UPPER
70S...IF NOT THE LOWER 80S ACRS THE WEST AND SOUTHWEST THIS
AFTERNOON. FEEL WARMING POTENTIAL IS ENOUGH TO WARRANT AT LEAST
SLIGHT CHANCE FOR POP-UP TYPE SHOWERS AND STORMS OVER THE NORTHERN
2/3'S OF THE CWA FROM LATE MORNING THROUGH MID AFTERNOON. SOME SPOTTY
ACTIVITY MAY FORM IN THE NORTHWEST SOONER THAN THAT...AS WEAK SFC
TROUGH AND MOISTURE CONVERGENCE RIBBON SAGS ACRS THAT AREA FIRST.
FEATURE WILL LOOK TO EVENTUALLY WASH OUT TODAY OVER THE LOCAL AREA AS
DEVELOPING NORTHERLY SFC FLOW SIGNALS ARRIVAL OF A PORTION OF
NORTHERN PLAINS SFC RIDGE.

SOME CLEARING WITH RIDGE AND LIGHT NORTH WIND TONIGHT...MAY BE
BETTER POTENTIAL FOR PATCHY FOG THAN CURRENT SITUATION...BUT WILL
LEAVE OUT MENTION FOR NOW AS UNSURE OF HOW WIDESPREAD ZONE
MENTIONABLE FOG POTENTIAL WILL BE AT THIS POINT.

RIDGE AXIS TO MAKE FOR A FAIR AND SEASONABLY WARM SATURDAY...EVEN
WITH ONGOING NORTH BREEZE. MIXING POTENTIAL OF PROGGED THERMAL
PROFILE SUGGESTS MUCH OF THE CWA SHOULD MAKE OR BREACH THE 80 DEGREE
MARK.

NO CHANGE TO LONGER RANGE(SUNDAY ON)...


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

$$

12