[LeArc] Forecast Discussion : MLI@ 5/27/2003 3:51:50 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 270850
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
350 AM CDT TUE MAY 27 2003

SURFACE RIDGE KEEPING WX VERY QUIET...WITH WEAK CYCLONIC FLOW ALOFT 
IN WAKE OF THE LOW THAT MOVED OVER THE AREA OVER THE WEEKEND.  500MB 
COLD POOL HELPED TO GENERATE CUMULUS OVER THE AREA ON MONDAY...WITH 
THE MOST COVERAGE OVER THE SOUTHERN COUNTIES.  UPPER LEVELS SHOW A 
STRONG UPPER LEVEL JET JUST MOVING ON SHORE OVER WASHINGTON/OREGON 
...ASSOCIATED WITH THE ONLY DECENT HEIGHT CHANGES OVER THE CONUS OF 
+150M RISES.  

MAIN CONCERNS THIS FORECAST INCLUDE TEMPERATURES TODAY AND 
TONIGHT...AND THE TIMING OF THE FRONT TO SWEEP THROUGH 
WEDNESDAY...AND ANOTHER ON FRIDAY.

00Z MODELS APPEAR TO HAVE INITIALIZED REASONABLY WELL...WITH SOME 
MINOR DIFFERENCES IN FRONTAL TIMING FOR WEDNESDAY.  MAIN DIFFERENCES 
LIE IN AVAILABLE MOISTURE FOR THIS FRONT...WITH THE AVN BRINGING IN 
SLIGHTLY HIGHER DEWPOINTS AT THE SURFACE THAN THE ETA.  AVN APPEARS 
TO HAVE THE BEST HANDLE ON CURRENT FIELDS...SO HAVE LEANED HEAVILY 
TOWARDS IT...BUT IN GENERAL AM GOING WITH A BLEND FORECAST.

TODAY HIGH TEMPS OUGHT TO BEGIN SHOWING EFFECTS OF WAA AT MID AND 
UPPER LEVELS...THOUGH NONE ONGOING AT SURFACE.  HAVE GONE BETWEEN 2 
AND 4 DEGREES OVER YESTERDAYS HIGHS...DUE TO CHANGE IN 850MB TEMPS.  
BY TONIGHT...WAA KICKS IN FINALLY AT SURFACE AND TEMPS STAY PRETTY 
WARM OVERNIGHT.  

WEDNESDAY A FAST MOVING FRONT SWINGS ACROSS THE AREA...BRINGING A 
CHANCE OF TSRA-  HAVE GONE WITH A HIGH CHANCE POPS...TRIED TO FINE 
TUNE SOME AND PICK OUT AN AREA FOR LIKELY...BUT COULD NOT QUITE DO 
THIS...AND DID NOT WANT ENTIRE AREA LIKELY JUST YET.  OUGHT TO BE 
JUST ENOUGH CONVERGENCE ACROSS AREA THAT SCATTERED PRECIPITATION 
OUGHT TO DEVELOP WITHOUT ANY PROBLEMS.  DUE TO DECENT SOUTHWEST FLOW 
AHEAD OF THIS TROUGH HAVE RAISED HIGHS A LITTLE WHERE THE FRONT WILL 
BE LATEST TO MOVE THROUGH.

THURSDAY LOOKS DRY AND QUIET...IN BETWEEN SYSTEMS...WITH TEMPS IN 
THE MID 70S.

EXTENDED...FRIDAY THROUGH MONDAY
NO CHANGES NEEDED AT THIS TIME.  THERE MAY BE A DELAY IN THE PRECIP 
FOR FRIDAY IF THE TRENDS IN THE LATEST MRF HOLD TRUE...PREVIOUS RUNS 
HAD BROUGHT THE FRONT THROUGH MORE QUICKLY.  SUNDAY AND MONDAY TO BE 
QUIET WITH ANOTHER RIDGE BUILDING IN.

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

$$

LE