[LeArc] Forecast Discussion : MLI@ 6/13/02 2:51:55 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 130751
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
250 AM CDT THU JUN 13 2002

SURFACE FRONT LINGERS ACROSS NORTHERN MO AND CENTRAL IL...WITH 
RECURRING SHOWERS AND THUNDERSTORMS TRACKING OVER CWA.  HAVE HAD 
SOME SEVERE WX...BUT MORE FLOODING.  UPPER LEVEL ANALYSIS CONTINUES 
TO INDICATE SUPPORT FOR SUCH ACTIVITY...WITH A DIFFUSE 850MB LEVEL 
FRONT OVER THE REGION....AND THE UPPER LEVEL LOW SPINNING SHORT 
WAVES OVER THE TOP OF THIS FRONT.  

MAIN CONCERN THIS FORECAST CONTINUES TO BE THE TIMING AND PLACEMENT 
OF PRECIPITATION.  MODELS REMAIN HIGHLY DIVERGENT...ESPECIALLY WITH 
QPF.  MODEL OF CHOICE IS AVN...MAINLY BECAUSE IT SEEMS TO HAVE BEST 
HANDLE ON SURFACE FEATURES AT 06Z.  HOWEVER...THINK IT IS ALSO 
AFFECTED BY CONVECTIVE FEEDBACK...AND HAVE TO TAKE QPF WITH GRAIN OF 
SALT.  

TODAY...SHORT TERM FORECASTING TECHNIQUES AND THE POSITION OF THE 
SURFACE LOW WOULD IMPLY THAT SHOWERS AND THUNDERSTORMS WILL BE 
LINGERING OVER AREA UNTIL MID MORNING.  WITH SO MUCH CURRENT WATER 
TROUBLE WILL HANG ON TO FLOOD WATCH FOR CURRENT LOCATIONS UNTIL MID 
MORNING.  WE SHOULD THEN BE DRY UNTIL INSTABILITY SHOWERS MOVE IN FROM 
NORTHWEST IN THE LATE AFTERNOON...MAINLY IN THE NORTH HALF OF THE 
CWA...AND LINGER INTO THE EVENING.  LOWER CHANCES OF SUCH SHOWERS 
FOR SOUTH CWA DURING THE EVENING.  HIGH TEMPS TODAY TO BE KEPT COOL 
BY CLOUDS AGAIN...AND WILL GO COOLER THAN WED DUE TO THE FRONT 
DROPPING FARTHER SOUTH.  WILL SPLIT THE DIFFERENCE BETWEEN FWC AND 
MAV TEMPS...LEANING TOWARDS THE MAV TEMPS AND GOING FCST.  TONIGHT 
COLD AIR ADVECTION CONTINUES...AND GOING SLIGHTLY BELOW GUIDANCE AS 
IN CURRENT FCST SEEMS REASONABLE.  

FRIDAY...IN THE AFTERNOON A COLD POOL MOVES OVER NERN SECTIONS OF 
CWA...ALLOWING INSTABILITY SHRA TO DEVELOP.  A FEW TSRA ALSO 
POSSIBLE WHERE LAPSE RATES ARE GREATEST.  THESE SHOWERS SHOULD DRY 
UP PRETTY QUICKLY AS SUN BEGINS TO DROP...AND WILL LEAVE OUT OF 
EVENING HOURS FOR NOW.  WILL STAY FAIRLY CLOSE TO MAV TEMPS OR 
SLIGHTLY COOLER DUE TO STRONG NORTHWEST FLOW.  

SATURDAY A FEW MORE INSTABILITY SHOWERS FOR THE FAR NORTHEAST... 
OTHERWISE DRY AND PARTLY CLOUDY.  COOL TEMPS TO CONTINUE.  

NO CHANGES TO EXTENDED EXPECTED AT THIS TIME.

.DVN...
IA...FLOOD WATCH UNTIL MID MORNING ALONG AND SOUTH OF INTERSTATE 80.
IL...FLOOD WATCH UNTIL MID MORNING ALONG AND SOUTH OF INTERSTATE 80. 
MO...FLOOD WATCH UNTIL MID MORNING.

LRE