[LeArc] Forecast Discussion : MLI@ 8/13/02 2:30:36 AM

Tue, 13 Aug 2002 02:30:36 -0500

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

FXUS63 KDVN 130732
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
230 AM CDT TUE AUG 13 2002

SYNOPTIC PICTURE THIS MORNING SHOWS 90KT BRANCH OF JET LIFTING THRU
MINNESOTA...WITH STRONGER 100KT BRANCH DIGGING INTO MONTANA. AT 500H A
LARGE AMPLITUDE TROF EXTENDS FROM A MANITOBA LOW THRU THE EASTERN
DAKOTAS INTO WESTERN NEBRASKA.  AT THE SURFACE...A COLD FRONT EXTENDS
FROM DBQ TO OTM AND SOUTHWEST TO A 1006MB LOW IN THE TEXAS PANHANDLE. A
WEAK SECONDARY LOW IS OVER EAST CENTRAL IOWA ALONG THE FRONT.

THE PRIMARY FORECAST CONCERN THIS PACKAGE IS IN THE SHORT TERM...WITH
THE COLD FRONT MOVING SOUTHEAST THRU THE FORECAST AREA THIS MORNING.  A
LOW MOVING NORTHEAST ALONG THE FRONT WILL HANG IT UP FOR A WHILE THIS
AFTERNOON AND EVENING...AND WILL PRODUCE ADDITIONAL RAINFALL.  ALSO OF
INTEREST IS A QUASI-COLD FRONT IN THE SATURDAY TIME FRAME...AND A
COLD FRONT MONDAY.

THE MODELS AGREE ON BRINGING THE COLD FRONT TO AROUND PIA BY 18Z...BUT
THAT'S WHERE THE AGREEMENT ENDS.  THE AVN AND NGM BRING A STRONG WAVE
NORTHEAST ALONG THE FRONT TO JUST SOUTH OF THE FORECAST AREA 18Z...WITH
THE AVN LIFTING IT NORTHEAST BY 00Z...AND THE NGM HANGING ON WITH THE
LOW TIL 00Z...THEN LIFTING IT NORTHEAST.  THE ETA NEVER PRODUCES A
WELL DEFINED WAVE ALONG THE FRONT. AFTER THE WAVE MOVES THRU...THE
FRONT CONTINUES MOVING SOUTHEAST TONIGHT...AND WASHES OUT OVER INDIANA
AND KENTUCKY WEDNESDAY NIGHT.  THE 500H TROF MOVES OVERHEAD AROUND 18Z
WEDNESDAY.  MEANWHILE...ANOTHER SURFACE TROF SETS UP IN THE HIGH
PLAINS MIDWEEK. A COLD FRONT POSSIBLY LAYS ACROSS THE AREA IN
THE SATURDAY TIME FRAME...BUT THE MEDIUM-RANGE MODELS ARE IN
DISAGREEMENT AS TO WHETHER OR NOT THIS FEATURE MAKES IT THIS FAR SOUTH
BEFORE HEADING NORTH.

CURRENT FORECAST HAS A GOOD HANDLE ON ONGOING PRECIP IN THE SHORT
TERM...ALTHO MAY HAVE TO HANG ONTO PRECIP SOUTHEAST THIS EVENING.
GOOD VV'S AND UPPER DIVERGENCE WILL ENHANCE PRECIP...MAINLY SOUTHEAST
HALF AND MAINLY THIS MORNING...ALTHO CONTINUING SOUTH THRU DAY.

MAY LOOK AT REDUCING PRECIP IN EXTENDED...AS MENTIONED FOR 4 CONSECUTIVE
DAYS...FRIDAY THRU MONDAY. MAY UP THE TEMPS A NOTCH TODAY AND TONIGHT.
MAY ALSO HAVE TO RAISE TEMPS A NOTCH FURTHER OUT IN TIME...AS COLD PUNCH
AFTER COLD FRONT IS RATHER WEAK.

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

REA