[LeArc] Forecast Discussion : MLI@ 5/28/02 2:02:21 PM

Tue, 28 May 2002 14:02:22 -0500

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

FXUS63 KDVN 281902
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
201 PM CDT TUE MAY 28 2002

SYNOPTIC PICTURE THIS AFTERNOON SHOWS 500H TROF EXTENDING FROM WESTERN
MN THROUGH WESTERN IA. AT THE JET LEVEL A 70KT EXTENDS FROM NORTHERN
WI ACROSS NORTHERN MI. AT THE SURFACE A TROF EXTENDS FROM THE CENTRAL
DAKOTAS THRU IOWA...FROM NORTHWEST TO SOUTHEAST...INTO SOUTH CENTRAL
IL. STRONG CONVECTION IS CURRENTLY EXPANDING ACROSS NORTH CENTRAL IOWA
IN ASSOCIATION WITH PVA...300H DIVERGENCE...AND 700H VV'S.

THE MODELS INITIALIZED WELL THIS MORNING.  THE MESO-ETA AND ETA HAVE
THE BEST HANDLE ON ONGOING PRECIP THIS AFTERNOON.

THE PRIMARY FORECAST CONCERN THIS PACKAGE IS PRECIP CHANCES OVER THE
NEXT 48 HOURS...WITH CHANGEABLE WEAK TO MODERATE FEATURES CHANGING IN
GUIDANCE FROM RUN TO RUN...WITH A TROF/COLD FRONT THURSDAY SWEEPING
WEATHER OUT TO THE EAST.

SHORT-TERM MODELS AGREE ON STRONG FORCING LATE THIS AFTERNOON AND THIS
EVENING AFFECTING THE NORTHERN PORTION OF THE FORECAST AREA. CAN'T
RULE OUT PRECIP FURTHER SOUTH ACROSS THE AREA EITHER...WITH BOUNDARIES
SET UP BY THIS MORNING'S RAINFALL SOUTH. 500H SHORT WAVE MOVES THRU
AROUND 12Z WEDNESDAY.  AT THE SURFACE...TROFING CONTINUES ACROSS IA
WEDNESDAY...WHICH WILL PROVIDE FORCING...MAINLY NORTH AND WEST.  THE
COLD FRONT MOVES THRU THE FORECAST AREA NEAR 12Z THURSDAY...WITH 500H
TROF IN THE 12Z-18Z TIME FRAME...AND PVA INTO THE AFTERNOON.

MEDIUM RANGE MODELS ARE MORE IN PHASE THAN ON YESTERDAY'S RUNS THRU
SATURDAY...WITH MRF NOW COMING MORE IN LINE WITH THE EUROPEAN'S LOWER
AMPLITUDE TROF...BUT THEY DIVERGE BY SUNDAY IN THE PLACING OF A
WARM/STATIONARY FRONT ACROSS THE AREA. THE MRF FORMS THE FRONT
SATURDAY NIGHT ALONG THE IA/MO LINE...LIFTING IT NORTH THRU THE FORECAST
AREA SUNDAY...THEN FORCING IT SOUTH AGAIN SUNDAY NIGHT WHERE IT
REMAINS INTO TUESDAY. THE EUROPEAN HAS A MORE NORTHERN SOLUTION THAT
COULD MAKE A SIGNIFICANT DIFFERENCE IN TEMPS AND PRECIP.

WILL CONTINUE FORECAST ON SAME TRACK. WILL KEEP LOW POPS TONIGHT AND
WEDNESDAY...AND MAYBE CUT BACK WEDNESDAY NIGHT.  MAY MENTION POPS OR
SPRINKLES THURSDAY IN AFTERMATH OF FRONT.  WILL HOLD OFF ON PRECIP FOR
SATURDAY...AS LOOKS LIKE BEST CHANCES...PER FMR AND MEX...START
SATURDAY NIGHT AND CONTINUE THRU TUESDAY.

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

REA