[LeArc] Forecast Discussion : MLI@ 6/11/02 2:44:35 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 110744
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
244 AM CDT TUE JUN 11 2002

CHALLENGING FORECAST THIS MORNING WITH SURFACE FRONT MOVING TOWARDS THE
FORECAST AREA...ACCOMPANIED BY A COMPLEX OF STRONG/SEVERE SHOWERS AND
THUNDERSTORMS.  UPPER LEVEL SUPPORT FOR THIS SYSTEM IS GOOD...WITH
850MB LLJ ACROSS KS/MO...AND WITH HIGH 850MB DEWPOINTS AND TEMPS.
UPPER LEVELS ALSO HAVE A SERIES OF 500MB SHORT WAVES TO MOVE ACROSS
IA...AND SIGNIFICANT DIFFLUENCE OVER THE UPPER MIDWEST.

ENTIRE FORECAST WILL BE A CHALLENGE THIS MORNING...WITH CHANCES OF
PRECIP INTO THURSDAY TO BE LOOKED AT.  LITTLE QUESTION ABOUT SOME
PERIODS...BUT WEDNESDAY/THURSDAY TIME FRAME TEMPS AND POPS COULD BE
TRICKY DUE TO QUESTIONS ABOUT POSITIONING OF SURFACE FRONT.

00Z MODELS APPEAR TO HAVE INITIALIZED FAIRLY WELL...THOUGH SOME
SIGNIFICANT PROBLEMS IN THE ETA WITH QPF...WITH THE AVN HANDLING
CURRENT CONVECTION BETTER...ONLY BEING A LITTLE ON THE HIGH SIDE.  NGM
HAVING SOME PROBLEMS WITH MAIN FEATURES AND WILL DISCARD FOR NOW.
PREFER POSITIONING OF THE SURFACE FRONT IN THE ETA...WITH THE AVN AT 06Z
TOO FAR SOUTHEAST.  SO...HAVE GONE WITH A BLEND OF THE MODELS FOR THIS
FORECAST.

TODAY...SHOWERS AND THUNDERSTORMS SHOULD CONTINUE TO REGENERATE AS THE
SURFACE FRONT DROPS SOUTHEAST TOWARDS THE CWA.  TIMING WILL BE TRICKY
WITH THIS MORNINGS CONVECTION AFFECTING THE MORNING HOURS...AND THEN
WITH AFTERNOON CONVECTION FIRING AGAIN.  AFTERNOON HOURS WILL BE
DEPENDENT ON WHERE THE STORMS RE-FIRE...WHICH AT THIS TIME APPEARS TO
BE OVER WESTERN IOWA.  FOR NOW...AM GOING TO GO WITH LOW CATEGORICAL 80
POPS FOR ENTIRE CWA FOR TODAY.  WILL ALSO BE INCLUDING FEW MAY BE
SEVERE WORDING AS WE ARE IN SLIGHT RISK IN SPC OUTLOOK...AND DUE TO
INSTABILITY AND VICINITY OF FRONT THINK THIS IS REASONABLE.  AS FAR AS
TEMPS...INCREASED CLOUD COVER WILL BE OFF SET BY COMPRESSIONAL HEATING
AHEAD OF FRONT.  MAY TONE DOWN CURRENT FCST A LITTLE...BUT NOT AS LOW
AS IN CURRENT GUIDANCE.

TONIGHT...AM PRETTY CONFIDENT IN CONTINUING SHOWERS AND THUNDERSTORMS
TONIGHT...BUT NOT AS CONFIDENT THAT COVERAGE WILL BE AS GREAT...SO
WILL LEAVE LIKELY POPS MUCH AS ARE IN CURRENT PACKAGE.  TEMPS TO BE A
LITTLE BIT OF A RACE TO SEE HOW FAR SOUTHEAST THE FRONT CAN GET BEFORE
MORNING.  WILL GO ON COOL SIDE IN THE NORTHWEST CWA...BUT SLOW
PROGRESSION OF FRONT WILL KEEP SOUTHEAST CWA FAIRLY CLOSE TO LOW TEMPS
THIS MORNING.

WEDNESDAY...WITH FRONT STILL LINGERING JUST SOUTH OF CWA...AM GOING TO
INCLUDE A CHANCE OF TSRA IN THE SOUTHERN HALF OF CWA...WITH ONLY SLIGHT
CHANCES NORTH.  BY WEDNESDAY NIGHT THE FRONT SHOULD DROP FAR ENOUGH
SOUTH FOR ONLY SLIGHT CHANCES IN FAR SOUTH.  TEMPS WILL BE VERY COOL...
AND WILL BE GOING COOLER THAN GUIDANCE.

THURSDAY...IN THE NORTHWEST FLOW...WITH A SIGNIFICANT COLD POOL ALOFT
OVER CWA...WE TYPICALLY GET SHOWERS IN THE AFTERNOON...SO HAVE THROWN
THESE IN WITH LOW POPS.  KEPT THEM TO MAINLY AFTERNOON WORDING...
THOUGH WOULD NOT BE SURPRISED TO TO SEE THEM SHOW UP IN THE MORNING
TOO.  TEMPS REMAIN COOL...GOING TEMPS AND GUIDANCE FAIRLY CLOSE SO WILL
ONLY TWEAK A LITTLE.

NO CHANGES TO EXTENDED THU-MON PLANNED ATTM.

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

LRE