[LeArc] Forecast Discussion : MLI@ 10/20/02 2:51:47 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 201959
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
300 PM CDT SUN OCT 20 2002

ONE LAST TRUE QUIET WX DAY BEFORE PATTERN GETS RATHER BUSY.  SURFACE 
WARM FRONT DEVELOPING OVER SRN SOUTH DAKOTA...EXTENDING INTO 
NORTHWEST IOWA.  THIS FRONT HAS JUST CLOUDS WITH IT FOR NOW.  
FURTHERN NORTH...THE 850MB FRONT OVER CENTRAL MN INTO WI PUTTING OUT 
SOME WHITE STUFF.  SURFACE HIGH STILL JUST NORTH OF CWA AT 18Z...BUT 
FALLS WITH SURFACE FRONT SHOULD KEEP HIGH MOVING EAST.  

MAIN FORECAST QUESTION IS THE TIMING AND TYPE OF PRECIPITATION 
THROUGH MID WEEK.

12Z MODELS STILL HAVE ENOUGH DIFFERENCES TO LOWER CONFIDENCE IN 
FORECAST...BUT ARE MUCH BETTER THAN YESTERDAY.  AVN HAS BEST HANDLE 
ON CURRENT SURFACE AND MID LEVEL FEATURES...WITH THE ETA JUST ENOUGH 
OFF KILTER TO MAKE IT SUSPICIOUS.  IN GENERAL...HAVE FOLLOWED AVN 
FOR MOST OF NEAR AND MID TERM FORECAST...WITH A LITTLE OF THE ETA IN 
THE NEAR TERM TO TONE BACK OVERDONE PRECIP TONIGHT THROUGH MONDAY 
NIGHT.  

ON MONDAY MORNING THE WAVE THAT BRUSHES THE NORTHERN FRINGES OF CWA 
HAS THE POTENTIAL FOR SNOW MIXED IN WITH THE RAIN.  HOWEVER...THIS 
POTENTIAL IS JUST THAT...AND WILL LEAVE OUT FOR NOW.  PRECIP CHANCES 
ARE SO LOW ANYWAY THAT AM ONLY GOING WITH A 20 POP FOR MONDAY AND 
MONDAY NIGHT.  MONDAY TEMPS ARE TOUGH...WITH FRONT MOVING THROUGH 
AROUND MID-DAY.  WILL GO SLIGHTLY WARMER THAN GOING 
TEMPS...ESPECIALLY SOUTH.  THIS IS ABOUT 4 DEGREES WARMER THAN MAV 
TEMPS...TO ACCOUNT FOR WARMING AHEAD OF FRONT WITH MORE SUNSHINE 
THAN AVN HAS.  

TUESDAY THE AVN TRIES TO BRING IN PRECIPITATION...BUT THIS SEEMS ON 
THE FAR FETCHED SIDE...WITH CONDENSATION PRESSURE DEFS DROPPING KIND 
OF FAST FOR THE ADVECTION PATTERN.  HAVE DELAYED UNTIL TUESDAY 
NIGHT...WHEN THE MAIN BAND OF PRECIP MOVES IN.  WILL INCREASE CLOUDS 
DURING DAY TO SHOW SLOW SATURATION.

EXTENDED...WED-SUN
MODELS COMING MORE IN LINE WITH A WEAKER VERSION OF THE GFS MODEL 
FROM 00Z YESTERDAY...AS WELL AS THIS MORNINGS GFS RUN FROM 00Z.  
SO...WEDNESDAY AND THURSDAY PRECIPITATION LOOKS ON TRACK...AND 
THOUGH MOST SITES WILL SEE PRECIPITATION...AMOUNTS WILL NOT BE VERY 
HIGH DESPITE LONG DURATION.  FORCING JUST NOT GOING TO BE THAT 
STRONG.  HAVE DROPPED LIKELIES TO HIGH CHANCE POPS. FRIDAY WILL HAVE 
DECREASING CLOUDS MOST LOCATIONS AS HIGH BUILDS OVER AREA.  SHOULD 
BE ANOTHER CHILLY NIGHT SATURDAY MORNING...SIMILAR TO THIS MORNING.  
SATURDAY THRU SUNDAY DAY LOOK DRY FOR NOW. SUNDAY NIGHT NEEDS SOME 
POPS WITH THE DEVELOPMENT OF ANOTHER INVERTED TROUGH LIKE SYSTEM 
OVER NRN TX.

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

LRE