[LeArc] Forecast Discussion : MLI@ 4/12/2003 3:45:11 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 122043
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
343 PM CDT SAT APR 12 2003

BRIGHT SUNNY DAY TODAY ACROSS THE CWA...WITH ONLY NORTHEASTERLY
BREEZE OFF LAKE MICHIGAN KEEPING TEMPERATURES FROM GETTING AS WARM
AS YESTERDAY.  AS IT IS...TEMPS VERY BALMY...IN THE 60S AND LOW
70S.  WEAKENING SURFACE FRONT DRAPED ACROSS MO AND SRN IL.  12Z
UPPER LEVEL ANALYSIS INDICATE RIDGE BUILDING OVER AREA...BUT HEIGHT
RISES NOT AS GREAT AS THEY WERE YESTERDAY.

MAIN CONCERN THIS FORECAST IS IN TEMPERATURES THROUGH TUESDAY...AND
THE ONSET OF PRECIP ON TUESDAY.

12Z MODELS APPEAR TO HAVE INITIALIZED JUST FINE.  GENERAL PREFERENCE
THIS PERIOD IS FOR THE GFS...MAINLY BASED ON ITS HANDLING OF THE
SURFACE LOW DEVELOPMENT ON TUESDAY.  THE GFS AND UKMET MODELS ARE
IN GOOD AGREEMENT WITH THEIR PREVIOUS RUNS WITH THE POSITION OF THE
SURFACE LOW OVER NORTHEAST NEBRASKA BY 84 HRS...OR 00Z WED...
TUESDAY EVENING.  ETA APPEARS TO BE TRYING TO BRING THIS FRONT
FARTHER AND FARTHER SOUTH...WHICH DOES NOT QUITE MAKE SENSE BASED ON
THE MID AND UPPER LEVEL FEATURES AND THE COLD SECTOR.

TEMPS TO GRADUALLY WARM THROUGH MONDAY...WITH BIGGEST JUMP TO BE ON
MONDAY...WHERE WE HAVE BEEN GOING AS MUCH AS 10 DEGREES OVER NGM
MOS GUIDANCE.  WILL BE CONTINUING THIS TREND...THOUGH TAPERED BACK A
LITTLE AS MIXING DOWN 850T WOULD INDICATE SLIGHTLY COOLER THAN WHAT
GOING TEMPS HAD.

HAVE DECIDED NOT TO CHANGE THE CURRENT ONSET OF PRECIPITATION
TUESDAY AFTERNOON/EVENING.  MODELS STILL HAVING SOME PROBLEMS
WITH TIMING OF THE INCOMING LOW CENTER...AND THE FAVORED AVN STILL
HAS SIMILAR TIMING TO GOING FCST.

EXTENDED...WEDNESDAY THROUGH SATURDAY
ACTIVE PATTERN WITH THE EXITING SYSTEM THAT BEGINS ON TUESDAY...AND
ANOTHER MOVING IN FOR NEXT SATURDAY.  MAIN QUESTION IS HOW LONG TO
HANG ONTO PRECIP AS THE SYSTEM EXITS FOR THURSDAY.  FOR NOW HAVE
DECIDED TO BUY THE MRF SOLUTION OF LINGERING PRECIP FOR WEDNESDAY
NIGHT AND THURSDAY...BUT DRY BY THURSDAY EVENING.  TYPICALLY THE
MODELS LIKE TO EJECT A SYSTEM LIKE THIS TOO QUICKLY.  MRF DOES WANT
TO START UP THE WAA PRECIP RATHER QUICKLY ON FRIDAY...FOR NOW HAVE
HELD OFF TO FRIDAY NIGHT AND SATURDAY.  THERE IS SOME QUESTION
ABOUT THE TIMING OF THIS SYSTEM...AND FEEL THAT IT WILL EVENTUALLY
BE DELAYED.

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

$$

LE