[LeArc] Forecast Discussion : MLI@ 5/28/2003 5:18:44 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 281013
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
510 AM CDT WED MAY 28 2003

RADAR TRENDS SHOWING THAT PRECIPITATION HAS MADE GOOD PROGRESS 
TOWARDS CWA OVERNIGHT...AND IS ALREADY INTO THE WESTERN FRINGES.  
LATEST SURFACE ANALYSIS INDICATING THAT SURFACE FRONT EXTENDING FROM 
KLSE TO BETWEEN KOMA AND KLNK.  THIS FRONT IS ACTUALLY ACTING MORE 
LIKE A WARM FRONT THAN A COLD FRONT...NO MATTER IT'S ORIENTATION AND 
COMING FROM THE NORTHWEST.  THE HIGHEST DEWPOINTS ARE POOLED BEHIND 
THE FRONT.  AT UPPER LEVELS...850 FRONT ALSO MORE A WARM FRONT..WITH 
SLIGHTLY WARMER TEMPS OVER MT AND ND AND SD THAN THERE ARE AHEAD OF 
THE FRONT AT KMSP AND KOAX.  

MAIN CONCERN THIS MORNING IS TIMING PRECIP IN..AND THEN BACK OUT OF 
THE AREA TODAY...AND THEN AGAIN FOR FRIDAY'S SYSTEM.  TEMPS TODAY 
ALSO OF CONCERN DUE TO FROPA THROUGH AREA.

00Z MODELS APPEAR TO HAVE INITIALIZED REASONABLY WELL...AND APPEAR 
TO BE HANDLING THIS CHAMELEON OF A WARM FRONT REASONABLY WELL.  
THERE ARE SOME PRETTY SIGNIFICANT TIMING DIFFERENCES FOR THE FRIDAY 
SYSTEM...WITH THE AVN SLOWER AND A STRONGER SHORTWAVE...AND THE ETA 
MUCH FASTER WITH A WEAKER SHORT WAVE.  FOR NOW...PREFER THE FASTER 
TIMING OF THE ETA. THE AVN WAS TOO STRONG AND TOO SLOW WITH THE 
CURRENT SYSTEM WHEN WE WERE LOOKING AT IT OVER THE WEEKEND.  
ALSO...THE AVN SOLUTION APPEARS TO PICK UP SOME ANOMALOUS 
STRENGTHENING OF THE MAIN SHORTWAVE AS IT MOVES OVER THE TOP OF THE 
RIDGE ON THURSDAY.  

TODAY THE MAIN STORY IS THE FRONT MOVING THROUGH...WITH THE 
PRECIPITATION ALONG AND AHEAD OF IT.  PRECIPITATION IS QUITE 
SCATTERED ALONG THE FRONT...WITH SOME SITES THAT HAVE REPORTED 
PRECIP ONLY TRACING OUT.  HAVE KEPT POPS IN THE CHANCE CATEGORY 
STILL TO ACCOUNT FOR THIS...EVEN THOUGH IT LOOKS PRETTY GOOD ON 
88D.  WIND BEHIND THE FRONT ALSO QUITE SIGNIFICANT...WITH GOOD 30 TO 
40 KT WINDS AT 850MB...AND LAPSE RATES BETWEEN THE SURFACE AND 850MB 
NEARLY DRY ADIABATIC AS OF 18Z...AND WITH WARMING TEMPS AT SURFACE 
DURING THE AFTERNOON LAPSE RATES SHOULD BE SUPERADIABATIC.  
SO...EXPECTING GUSTS TO AROUND 30 KTS MOST OF THE CWA...A LITTLE 
HIGHER NORTH.  NO NEED FOR ADVISORY...BUT WILL BE DEFINETELY WINDY.

TONIGHT AND THURSDAY TO BE FAIRLY QUIET...WITH RIDGING OVER THE CWA.

THURSDAY NIGHT AND FRIDAY SEE THE NEXT FRONT MOVING THROUGH THE 
AREA.  TIMING OFF THE ETA WOULD BRING PRECIP INTO WESTERN AREAS OF 
CWA BY VERY EARLY MORNING DURING THE THURSDAY NIGHT PERIOD...VERY 
SIMILAR TO CURRENT SYSTEM.  SO...HAVE INTRODUCED SLIGHT CHANCE TO 
THURSDAY NIGHT...AND SINCE THE SYSTEM WILL BE MOVING THROUGH FASTER 
THAN PREVIOUS FORECASTS...HAVE LOWERED POPS FOR FRIDAY NIGHT...EVEN 
DRY IN A FEW LOCATIONS.

MADE NO CHANGES TO EXTENDED TIME FRAME.  

APOLOGIES FOR LATE AFD...

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

$$

LE