[LeArc] Forecast Discussion : MLI@ 6/20/02 2:08:14 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 201909
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
208 PM CDT THU JUN 20 2002

SYNOPTIC PICTURE THIS AFTERNOON SHOWS LARGE RIDGE AT 500H OVER
ILLINOIS...MISSOURI...AND KANSAS...WITH A TROF ALONG THE WEST COAST.
AT THE SURFACE...A STATIONARY FRONT EXTENDS FROM OMA TO BETWEEN DEH
AND DBQ...WITH LOW 70S DEW POINTS SOUTH AND NEAR 60 NORTH.  CONVECTION
IS BEGINNING TO FIRE ACROSS NORTH CENTRAL AND NORTHEAST IOWA JUST
NORTH OF FRONT.  THE MODELS INITIALIZED WELL AT 12Z.

THE PRIMARY FORECAST CONCERN THIS PACKAGE IS IN NEAR TERM...WITH
STATIONARY FRONT PROVIDING FOCUS TONIGHT THRU FRIDAY MORNING...
MAINLY NORTH...AND POSSIBLY AGAIN FRIDAY EVENING...AGAIN NORTH.

MODELS AGREE ON STATIONARY FRONT ACROSS NORTHERN PORTION OF FORECAST
AREA TONIGHT...POSSIBLY LIFTING A BIT NORTH FRIDAY AFTERNOON...ALTHO
ETA HINTS AT LINGERING BOUNDARIES ACROSS FORECAST AREA THRU AFTERNOON
FRIDAY. MODELS LIFT FRONT SLIGHTLY NORTH FRIDAY NIGHT...AND THEN WELL
NORTH SATURDAY. AFTER THAT...WE REMAIN WARM SECTOR THRU 120 HOURS/
12Z TUE. MEDIUM RANGE MODELS INDICATE FRONT THRU FORECAST AREAS IN
TUESDAY TIME FRAME. AT 500H A SHORT WAVE MOVES ACROSS NORTHERN SECTIONS
LATE TONIGHT INTO FRIDAY MORNING...WITH ANOTHER SHORT WAVE IN THE
TUESDAY TIME FRAME...AND POSSIBLY A FEW OTHER VERY WEAK WAVES IN
BETWEEN.

THERMALLY-DRIVEN NON-SEVERE CONVECTION SHOULD FIRE ACROSS MAINLY
NORTHWEST HALF OF FORECAST AREA THIS EVENING...ALONG FRONT.  STRONGER
CONVECTION WILL FIRE WEST ON NOSE OF LLJ NORTH OF OMA...AND MOVE INTO
NORTHEAST IOWA LATE. THIS WILL BE SUPPORTED BY STRONG 300H DIVERGENCE...
AND STRONG VV'S...WELL INTO MORNING...MAINLY NORTH. OUTFLOW BOUNDARIES
COULD BRING PRECIP WELL SOUTH THROUGH CENTRAL PORTION OF FORECAST
AREA.  WILL HAVE CHANCE OF TSTMS AGAIN FRIDAY EVENING FAR NORTH...WITH
LATE NIGHT ACTIVITY FOCUSING NORTH OF AREA.

WILL KEEP SAME STRONG GRADIENT OF POPS FROM NORTH TO SOUTH. MAY TAKE
OUT PRECIP CHANCES MONDAY...BUT LEAVE IN TUESDAY. LOW MOVING UP INTO
LOWER MISSISSIPPI VALLEY MONDAY COULD BRING PRECIP MONDAY NIGHT FROM
SOUTH...BUT FEEL TUESDAY BEST SHOT.

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

REA