[LeArc] Forecast Discussion : MLI@ 7/3/2003 11:50:47 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 031647
AFDMLI

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1148 AM CDT THU JUL 3 2003

UPDATED ZFP AND GRIDS TO REFLECT DIMINISHING MCS MOVING OUT OF THE 
CWA. WITH LITTLE IN THE WAY OF CIRRUS DEBRIS REMAINING...STRONG 
HEATING IS TAKING PLACE.  WILL BUMP UP HIGHS SLIGHTLY IN THE WEST 
AND NORTH.  CONTINUED SLIGHT CHANCE OF AFTERNOON STORMS WITH 
BOUNDARY LINGERING ACROSS THE CENTRAL (NORTHWEST TO SOUTHEAST) CWA. 
WILL WATCH CLOSELY FOR ISOLATED CELLS FORMING IN A HIGH CAPE 
ENVIRONMENT THIS AFTERNOON.  A SEVERE STORM REMAINS POSSIBLE IF WE 
CAN BREAK THE CAP.  TO HELP DETERMINE THIS POSSIBILITY...AN 18Z 
SOUNDING WILL BE SENT BY DVN TODAY. 

ERVIN

................................................

PREVIOUS AFD ISSUED 424 AM CDT THU JUL 3 2003...

IMPRESSIVE MCS ACROSS MN MAKING SLOW PROGRESS TO THE SOUTH SOUTHEAST
THIS MORNING...WEAKENING GRADUALLY. LATEST SURFACE ANALYSIS
DEPICTING THE SURFACE FRONT MOVING INTO THE DAKOTAS...WITH THE MCS
HAVING DEVELOPED ON A LEADING TROUGH EXTENDING FROM NORTHERN
MINNESOTA TO CENTRAL NEBRASKA.  THE MCS IS MOVING INTO AN AREA THAT
IS A LITTLE LESS UNSTABLE...WITH JUST A LITTLE LESS MOISTURE
AVAILABLE...AND SHOULD CONTINUE TO WEAKEN AS IT MOVES SOUTH.

THROUGH FRIDAY NIGHT...

PER MODEL DIAGNOSIS...CURRENT MCS ACROSS MINNESOTA/WISCONSIN SHOULD
MISS THE CWFA THIS MORNING. NARROW BAND OF SHRA IS A RESULT OF WEAK
CONVERGENCE/LIFT. THESE SHOULD DISSIPATE AROUND MID MORNING AND ONLY
AFFECT ABOUT THE NORTHWEST THIRD OF CWFA. BOUNDARY FROM MCS SHOULD
LAY OUT OVER OR JUST NORTH OF CWFA AND BE FOCUS FOR CONVECTION TO
DEVELOP THIS AFTERNOON. NEXT MCS SHOULD DEVELOP INITIALLY AS
SUPERCELLS IN THE KFSD TO KEST AREA AND COALESCE INTO A SEVERE MCS
THAT MOVES ESE ACROSS NORTHERN IOWA OVERNIGHT...SIMILAR TO TONIGHTS.
SIGNALS FROM MODELS SUGGEST POTENTIAL BOW THAT EVENTUALLY EVOLVES
INTO A HEAVY RAIN EVENT. MOST LIKELY AREA IS NORTHERN 2/3RDS OF CWFA
WITH AREAS NORTH OF HIGHWAY 30 AT GREATEST RISK FOR DAMAGING WINDS.

MCS TO DISSIPATE BY MID DAY FRIDAY AND LAY OUT A BOUNDARY ACROSS
SOUTH THIRD OF CWFA...TO INITIATE CONVECTION BY LATE AFTERNOON. THIS
LATE AFTERNOON CONVECTION LIKELY TO BE SEVERE AS WELL INTO EARLY
EVENING BEFORE EVOLVING INTO ANOTHER SEVERE MCS. APPEARS THAT SOUTH
THIRD TO SEE HEAVY RAIN FRIDAY NIGHT.

AREA IS QUITE DRY SO THE GROUND SHOULD TAKE THIS RAIN WITH NO
PROBLEM. DAY SHIFT MAY WANT TO RE-EVALUATE THIS. HEAT INDICES TODAY
SHOULD BE NEAR BUT BELOW ADVISORY CRITERIA FOR THE AREA.

SATURDAY THROUGH SUNDAY MORNING TO BE FAIRLY QUIET ACROSS THE
AREA...BETWEEN SYSTEMS WITH THE FRONT OF THURSDAY AND FRIDAY FINALLY
OFF TO THE SOUTH...AND A NEW SYSTEM DEVELOPING OVER THE PLAINS WHICH
WILL DRAG A WARM FRONT ACROSS THE AREA SUNDAY NIGHT.  DID GO WITH
SOME LINGERING SHOWERS ACROSS THE SOUTH SATURDAY MORNING.  KEPT TEMPS
RELATIVELY COOL...AND CLOSE TO GUIDANCE THESE PERIODS. SUNDAY NIGHT
THROUGH TUESDAY TO BE BUSY...WITH ANOTHER SLOW MOVING FRONT DROPPING
ACROSS THE AREA ON MONDAY...ONLY TO STALL OUT JUST TO THE SOUTH OF
THE CWA THROUGH TUESDAY.  FOR MOST PART...WENT ABOVE GUIDANCE ON
MONDAY WITH THE FRONT MOVING THROUGH...BUT THEN KEPT PRETTY CLOSE TO
GUIDANCE FOR REMAINDER OF PERIOD. WEDNESDAY MAY EVENTUALLY ALSO NEED
PRECIP...AS THE NEW MRF DEVELOPING A NICE LITTLE MCS OVER IA TUESDAY
NIGHT.  FOR NOW HAVE KEPT THIS PERIOD DRY...THOUGH LATER MODELS MAY
CAUSE A CHANGE IN THINKING.

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

$$

LE/SF