[LeArc] Forecast Discussion : MLI@ 11/10/02 2:30:04 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 100840
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
240 AM CST SUN NOV 10 2002

SURFACE ANALYSIS AT 07Z INDICATED TWO MAIN WEAK LOW CENTERS...ONE 
NEAR KCID AND THE IN SOUTHWEST WI. A COLD FRONT REACHED SW FROM THE 
IA LOW INTO CENTRAL OK. FRONT/TROUGH IS CURRENTLY DRY ONLY WEAK 
LOW LEVEL CONVERGENCE AND PRECIPITATION CONFINED WELL TO E-SE IN 
WARM SECTOR. BREAK IN CLOUD COVER OVER CWFA ALONG WITH WEAK 
CONVERGENCT WIND FIELDS AND SURFACE DEWPOINTS IN UPPER 40S TO LOWER 
50S RESULTING IN DENSE FOG DEVELOPING OVER EASTERN IA AND WILL HAVE 
TO MONITOR TRENDS FOR INCLUSION IN EARLY FIRST PERIOD.

THE REAL COLD PUSH IS A COUPLE HUNDRED MILES TO THE WEST 
NORTHWEST...WITH SECONDARY FRONT FROM ABOUT W CENTRAL MN TO SW 
NEB...BEHIND H85 TROUGH. AT UPPER LEVELS...STRONG UPPER JET PUSHING 
INTO SOUTHERN PLAINS DIGGING TROUGH AXIS FROM MANITOBA TO EASTERN CO.
INTIAL FORECAST CHALLENGE IS SHORT TERM FOG AND TEMPERATURE TRENDS 
AS COLD AIR ADVECTION INCREASES TODAY...AND THEN PRECIPITATION 
TONIGHT AS SECONDARY SURFACE ROTATES THROUGH WITH UPPER LEVEL 
SURPORT.

AT SURFACE...AVN WAS CLOSEST TO MSAS ANALYSIS PRESSURE FIELDS AT 
06Z. CONSIDERABLE DISAGREEMENT IN SHORT TERM MODELS WITH HANDLING OF 
THIS CYCLONE AS IT MOVES NORTHEAST ACROSS GREAT LAKES TODAY...THEN 
NE INTO QUEBEC MONDAY. ALL ARE SIMILAR WITH MAIN TRENDS TO IMPACT 
CWFA....BUT WILL TREND CLOSEST TO AVN WITH ITS BETTER EARLY 
VERIFICATION AND SUPPORT FROM STRONG PRESSURE FALL TRENDS OVER 
NORTHERN LOWER MI FAVORING THE FASTER SOLUTION. COLD FRONT AT H85 
CURRENTLY OVER NW IA LOOKS TO BRING STRONG COLD AIR ADVECTION PUSH 
ACROSS MISS RIVER AROUND 18Z...THEN EASTWARD ACROSS IL IN AFTERNOON.
CURRENT FORECAST HAS THIS TRENDED WELL WITH MORNING HIGH WORDING IN 
WEST AND BRISK WINDS. GUIDANCE AGAIN SHOWING WIDE RANGE FOR 
HIGHS...WITH MET WAY TOO WARM. CURRENT TRENDS LOOK GOOD WITH NEAR OR 
BELOW MAV VALUES FOR NW IN UPPER 40S...AND CLOSE TO MAV CENTRAL AND 
SE. THE FRONT CURRENTLY DRY AND SEE NO REASON FOR IT TO BEGIN 
PRECIPITATING LATER TODAY AND WILL KEEP DRY FIRST PERIOD.

TONIGHT...CROSS SECTIONS SHOW DEEP SATURATION WITH SURFACE TROUGH 
PUSHING SOUTH ACROSS AREA BETWEEN 06Z AND 12Z AT SAME TIME UPPER 
TROUGH SLIDES THROUGH FROM WEST. BEST FORCING AND LOW LEVEL 
CONVERGENCE FAVORS E CENTRAL IA ZONES AND NW IL LATE WITH PRECIP 
POSSIBLY LINGERING IN NE INTO EARLY DAYLIGHT MONDAY. THERMAL 
PROFILES FAVOR SNOW...BUT ONLY LIGHT QPF EXPECTED AND RELATIVELY 
WARM GROUND WILL PRECLUDE ANY ACCUMULATION. WILL RAISE POPS TO HIGH 
SCATTERED IN NORTH AND KEEP FLURRIES FOR FAR SOUTH. GUIDANCE LOWS 
FROM 00Z SOMEWHAT WARMER THAN 12Z RUN...BUT LOOK TOO WARM AND WILL  
UNDERCUT. 

LONGWAVE TROUGH AXIS LINGERS JUST TO EAST THROUGH TUESDAY WTIH 
SURFACE RIDGING EDGING IN FROM WEST TO PROVIDE COOL AND DRY 
CONDITIONS EARLY WEEK...THEN FLOW BECOMES MORE ZONAL FOR MIDWEEK 
WARM UP. LATEST MRF/GFS SUPPORTS CURRENT FORECAST WITH PROGRESSIVE 
LATE WEEK PATTERN AND PRECIP CHANCES AND SEE NO REASON FOR 
CONSIDERABLE CHANGES AT THIS TIME. 

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

DLS