[LeArc] Forecast Discussion : MLI@ 5/23/02 2:56:47 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 231956
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
255 PM THU MAY 23 2002

SHOWERS AND THUNDERSTORMS THAT AFFECTED THE AREA THIS MORNING HAVE 
EXITED OFF TO THE EAST AND DIMINISHED QUITE NICELY.  CLOUDS OVER 
AREA NOW KEEPING DOWN ANY NEW DEVELOPMENT...SO MAY HAVE TO WAIT FOR 
OVERNIGHT CONVECTION TO BREAK OUT BEFORE ANYTHING GETS TO THE CWA.  
SURFACE ANALYSIS INDICATING FRONT OVER CENTRAL IOWA...MOVING VERY 
SLOWLY EAST.  MOISTURE POOLING NICELY AHEAD OF IT...WITH DEWPOINTS 
IN THE UPPER 50S ACROSS CWA...AND MID 60S OVER EASTERN KS. 

MAIN FORECAST PROBLEM TODAY IS THE TIMING AND LOCATION OF THE NEXT 
TWO WAVES OF PRECIPITATION.  

12Z MODELS APPEAR TO HAVE INITIALIZED ALL RIGHT...BUT THERE ARE SOME 
SIGNIFICANT PRECIPITATION PROBLEMS BY 18Z...WITH BOTH ETA AND AVN 
PUTTING OUT WAY TOO MUCH PRECIPITATION FOR THAT 6HR PERIOD...RAINING 
WHERE ITS NOT.  ETA SEEMS TO BE SLIGHTLY BETTER...WITH A REASONABLE 
HANDLE ON THE PRECIP NOW MOVING OUT OF OK INTO SERN KS.  IF YOU 
IGNORE THE EXTRA PRECIP TO THE NORTHEAST...THE MAIN AXIS OF PRECIP 
IS IN THE RIGHT SPOT.  SO...IN GENERAL ARE FAVORING THE ETA FOR THIS 
FORECAST.  FRONTAL POSITIONS ARE SIMILAR...SO AM NOT QUITE SURE WHY 
AVN IS PUTTING OUT SO MUCH QPF OVER SRN CWA.  CAN ONLY NOTE THAT 
VORT MAX IS FURTHER NORTH ON AVN...THOUGH THINK THIS WOULD ALSO 
AFFECT FRONT.  SO...FEEL THERE IS SOMETHING NOT QUITE RIGHT. 

TONIGHT WILL BE TRICKY WITH THE FRONTAL POSITION DICTATING WHERE THE 
NEXT MCS LAYS DOWN THE PRECIPITATION.  FOR NOW...AM FAVORING THE ETA 
POSITION WITH MAX PRECIP BAND TO SOUTH OF CWA.  WITH LOW FLASH FLOOD 
GUIDANCE VALUES OVER THE SOUTHERN PORTIONS OF CWA THERE MAY BE SOME 
LOCALIZED PROBLEMS...BUT PROBABLY NOT WORTH A WATCH.  

TOMORROW NIGHT IS THE BIG PROBLEM.  BOTH THE AVN AND ETA BOTH AGREE 
ON BRINGING A BIG SWATH OF PRECIP ACROSS CWA...WITH QPF AMOUNTS IN 
THE HALF-INCH RANGE.  SCATTERED AMOUNTS OF 1-2 INCHES ARE MORE 
LIKELY...AND TONIGHTS MID SHIFT OR TOMORROWS DAY SHIFT MAY NEED TO 
ISSUE A FLOOD WATCH FOR THIS AS LONG AS MODELS REMAIN CONSISTENT.  
WILL ISSUE ESF FOR NOW TO GET THE WORD OUT.

EXTENDED...SUN-THU
LATTER HALF OF MEMORIAL WEEKEND LOOKING DRY...BUT WITH A WARMING 
TREND.  SUNDAY LOOKS COOL WITH NE FLOW OFF LAKE MI...BUT MONDAY WE 
TURN BACK S AND WAA SHOULD CAUSE A REASONABLE JUMP.  A FRONT DROPS 
SOUTHEAST ACROSS MIDWEST DURING THE WEEK...SIMILAR TO THE CURRENT 
SITUATION.  THUS...LATTER 3 DAYS OF FCST NEED CHANCES OF SHOWERS AND 
TSTMS...EVEN THOUGH THIS REALLY LOOKS WISHY-WASHY.  TEMPS SHOULD BE 
WARM ON TUESDAY WITH THE FRONT TO MOVE THROUGH AREA.  WEDNESDAY AND 
THURS GUIDANCE TEMPS LOOK TOO WARM...THE MRF IS KEEPING THE FRONT TO 
THE NORTH.  PREFER THE MORE SOUTHERLY SOLUTION OF THE UKMET AND 
ECMWF...KEEPING THE FRONT SOUTH OF THE CWA.

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

LRE