[LeArc] Forecast Discussion : MLI@ 9/25/02 3:10:08 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 250818
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
315 AM CDT WED SEP 25 2002

SHOWERS FROM CENTRAL IA MOVING INTO WESTERN PARTS OF CWA TRIGGERED 
BY STRONG WAA AND ISENTROPIC LIFT OVER PLAINS.  MUCH OF THE LIFT 
BREAKS DOWN BY 12Z...AND RE-FOCUSES OVER NE AND SD.  SHRA WILL ALSO 
HAVE TO DEAL WITH INCREASINGLY DRY LOW LEVELS AND THE SUBSIDENCE 
ASSOCIATED WITH THE SURFACE RIDGE CENTERED OVER MI.  INCREASED 
CLOUDS KEEPING TEMPS ON THE WARM SIDE...AND ONLY HAVE FALLEN INTO 
THE MID TO UPPER 40S AS OF 07Z.  

FORECAST PROBLEMS THIS MORNING INCLUDE TEMPS TODAY IN CONTINUING 
STRONG WAA...AND POPS TONIGHT THROUGH FRIDAY.

00Z MODELS APPEAR TO HAVE INITIALIZED FAIRLY WELL...BUT NONE REALLY 
SEEM TO HAVE PICKED UP ON THE CURRENT BATCH OF PRECIPITATION.  
OTHERWISE...MODELS ARE FAIRLY SIMILAR FOR THE FIRST 24 HOURS.  AVN 
SEEMS TO AT LEAST HINT AT THIS PRECIPITATION...AND IN GENERAL PREFER 
ITS SOLUTION FOR THIS FORECAST.  IT PICKS UP SOME CONVECTIVE 
FEEDBACK PROBLEMS BY THURSDAY MORNING...SO HAVE BLENDED IN THE ETA 
AT THIS POINT. 

MODELS REALLY SLOW DOWN PROGRESSION OF FRONT...AND HAVE KEPT PRECIP 
OUT OF TODAY.  THINK A SIMILAR OCCURRENCE TO WHAT OCCURRED THIS 
MORNING POSSIBLE AGAIN TONIGHT.  AS CONFIDENCE IS LOW...HAVE JUST 
SLCHC POPS GOING NORTHWEST.  BY THURSDAY FRONT GETS CLOSE ENOUGH TO 
NEED SOME CHANCE POPS NORTHWEST...AND MUCH OF THE AREA THURSDAY 
NIGHT.  WITH THE FRONT SLOWING DOWN...HAVE PUT A SLIGHT CHANCE OF 
SHRA INTO EASTERN ZONES FOR FRIDAY MORNING.  

TEMPS TOUGH TODAY...WITH THE POTENTIAL FOR A BIG BUST IF MUCH 
SUNSHINE BREAKS THROUGH AFTER SHOWERS MOVE THROUGH.  WILL STICK 
FAIRLY CLOSE TO MAV TEMPS...GOING A LITTLE WARMER IN THE SOUTHWEST 
PART OF THE CWA...AS THIS IS WHERE SUNSHINE IS MOST LIKELY TO GO 
THROUGH.  THURSDAY ALSO TOUGH WITH FRONT IN THE VICINITY...WITH THE 
POTENTIAL FOR TEMPS TO RISE INTO LOW 80S AHEAD OF FRONT...BUT IF 
FRONT UNDULATES SOUTHEAST...TEMPS COULD BE DOWN IN THE LOW TO MID 
60S.  FOR NOW WILL STICK FAIRLY CLOSE TO GOING FCST...AND WILL WAIT 
UNTIL MODELS CAN GIVE A BETTER IDEA ON FRONT BEFORE SEE SAWING 
AROUND THE FCST.

DO NOT ANTICIPATE MAKING ANY CHANGES TO EXTENDED AT THIS TIME... 
THERE IS SIGNIFICANT UNCERTAINTY IN THE LONG RANGE MODELS...WITH 
TIMING AND POSITIONING DIFFERENCES.

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

LRE