[LeArc] Forecast Discussion : MLI@ 7/9/02 2:49:53 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 090748
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
247 AM CDT TUE JUL 9 2002

SYNOPTIC PICTURE THIS MORNING SHOWS 500H SHORT WAVE RESPONSIBLE FOR
THE PAST 8 HRS PRECIP HAS MOVED JUST EAST OF THE FORECAST AREA. A STRONG
HIGH SITS OVER UTAH...WITH A RIDGE EXTENDING EAST ACROSS THE SOUTH.
TO THE NORTHWEST...A VIGOROUS SHORT WAVE...WHICH WILL BE A PLAYER
IN OUR WEATHER ON WEDNESDAY AND THURSDAY...WAS ROUNDING THE TOP OF THE
RIDGE IN SOUTHERN ALBERTA.  AT THE SURFACE THE COLD FRONT IS PROGRESSING
SLOWLY SOUTHEAST...AND WAS JUST NORTH OF THE QUAD CITIES AT 07Z.
TRAILING PRECIP BAND...EXTENDING FROM CEDAR RAPIDS EAST ACROSS THE
AREA...IS ASSOCIATED WITH THE 850H FRONT.

THE PRIMARY FORECAST CONCERNS THIS PACKAGE ARE THREE-FOLD. FIRST IS
LINGERING PRECIP THIS MORNING. SECOND IS SKY COVER TODAY...WHICH WILL
BE MORE THAN PREVIOUSLY EXPECTED. THIRD IS PRECIP CHANCES ASSOCIATED
500H TROF...AND INVERTED SURFACE TROF...IN THE WEDNESDAY/THURSDAY
PERIOD.

THE MODELS INITIALIZED WELL AT 00Z. THEY AGREE ON THE COLD FRONT
MOVING SOUTH OF THE FORECAST AREA BY OR AROUND 18Z...AND CONTINUING
WELL SOUTH OVER THE NEXT 24 HOURS.  PRECIP WILL LINGER IN SOME EASTERN/
SOUTHEASTERN COUNTIES EARLY TODAY.  THE 850H LOW WILL KEEP CLOUDS
ACROSS THE AREA...ESPECIALLY EAST. HIGH SUN ANGLE COULD LIMIT CLOUD
COVER ON IOWA SIDE.  SHORT AND MEDIUM RANGE MODELS IN SOME DISAGREEMENT
ON THE 500H TROUGH...WHICH WILL MOVE OVER WESTERN/CENTRAL IOWA
WEDNESDAY...WITH STRONG PVA...AND DIVE SOUTH THURSDAY.  BEST ESTIMATE
IS THAT WAVE WILL JUST GRAZE WESTERN EDGE OF DVN FORECAST AREA.
TROUGH WILL...HOWEVER...PULL COOLER AIR INTO REGION FOR SECOND HALF OF
WEEK.

WILL PROBABLE INCREASE CLOUD COVER EAST.  WILL ADJUST PRECIP
ASSOCIATED WITH NEXT WAVE TO EARLIER TIME...WEDNESDAY AND WEDNESDAY
NIGHT...AND RESTRICT TO WEST.  MAY ADD A LITTLE SKY COVER IN FRIDAY
THRU MONDAY PERIOD...BUT SHOULD BE DRY SO MAY ALSO LEAVE AS IS.

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

REA