[LeArc] Forecast Discussion : MLI@ 12/9/02 2:38:12 PM

[Richard R. Sample]

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


FXUS63 KDVN 092053
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
250 PM CST MON DEC 9 2002


QUIET WX TO CONTINUE THROUGH MID WEEK. SFC HIGH RIDGE NOW TO OUR 
SOUTH FROM NRN MO INTO LAKE ERIE AT 18Z.  REGION STILL IN  NW FLOW 
AT H5 BUT WITH CANDIAN VORTEX NOW INTO NEWFOUNDLAND AND W COAST 
RIDGE BUILDING EAST...FLOW IS TAKING ON A MORE WESTERLY COMPONENT.

MAIN CONCERN IN THE SHORT TERM WILL BE TEMPS TONIGHT AND IMPACT OF 
STRATUS FIELD OVER THE SOUTHERN PLAINS.  MODELS WERE IN GOOD 
AGREMENT THIS MORNING WITH LITTLE DIFFERENCES NOTED. H5 LOW OVER TX 
WAS SPREADING SOME HIGH CLOUDS NE THROUGH MO THIS AFTERNOON.  GFS 
WAS DOING A REASONABLY GOOD JOB WITH THE HIGH LEVEL RH WITH THIS 
SYSTEM AND WAS SPREADING IT INTO OUR EASTERN CWA THIS EVENING.  REST 
OF CWA SHOULD SEE LITTLE IN THE WAY OF CLOUDS TONIGHT.  SURFACE 
RIDGE TO OUR SOUTH IS PROGGED TO REMAIN NEARLY STATIONARY...SO WIND 
SHOULD DECOUPLE THIS EVENING. LIGHT WIND AND DRY AIR (SFC DEW POINTS 
AROUND 10 LATE THIS AFTERNOON) SHOULD SEE GOOD TEMP DROP EVEN WITH 
SOME CI IN THE EAST.  HAVE LOWERED MINS TONIGHT A CATEGORY...CLOSE 
TO MET NUMBERS.  

STRATUS OVER SOUTHERN PLAINS SHOULD START TO MOVE NE LATE TONIGHT 
EARLY TUESDAY.  BASED ON META MOISTURE FIELDS FEEL STRATUS A GOOD 
POSSIBLITY BY LATE TUESDAY NIGHT.  SHOULD STILL SEE SOME SUN TUESDAY 
AND LEFT FCST PRETTY MUCH AS IS BUT MADE ADJUSTMENTS  TUESDAY NIGHT 
INTO THURSDAY ANTICIPATING ARRIVAL OF STRATUS.  HAVE PULLED BACK  
MAX TEMPS AND RAISED MINS ABOUT A CATEGORY EACH.  FURTHER 
ADJUSTEMENTS WILL PROBABLY BE NEEDED IF CONFIDENCE INCREASES.  ALSO 
ADDED IN A LOW POP FOR SOME -RN THURSDAY AFTERNOON BASED ON LOW 
LEVEL ISENTROPIC LIFT...LOW CONDENSTATION PRESSURE DEFICITS AND 
REGION IN AREA OF H5 DIFFLUENT FLOW OF SRN STREAM UPPER LOW. MODELS 
STILL SHOWING SOME DIFFERENCES IN TIMING AND TRACK OF THIS 
SYSTEM...SO FEEL IT IS BEST TO LEAVE R/S WORDING IN FORECAST UNTIL
MODELS GET A BETTER HANDLE ON IT.

EXTENDED (FRI-MON)
LARGE SYSTEM PROGGED TO MV THROUGH ACROSS THE SOUTHERN PLAINS AND 
LOWER AND MID MISSISSIPPI VALLEY LATE THIS WEEK STILL HAS A LOT OF
UNCERTAINTIES WITH RESPECT TO TIMING AND TRACK.  00Z RUNS OF THE 
GFS/UKMET CONTINUE TO SUGGEST SLOWER MOVEMENT WHILE 06Z GFS IS
FASTER THAN 00Z SOLUTION.  AS A RESULT WILL NOT MAKE MANY CHANGES TO
THE GOING EXTNEDED FOR FRI/SAT.  SYSTEM STILL LOOKS WARM ENOUGH TO 
SUPPORT MAINLY LIQUID PCPN ESPECIALLY IN THE SOUTH WHERE PCPN THREAT 
IS THE GREATEST...BUT -SN NOT OUT OF THE QUESTION AND IS DEPENDENT 
ON TIMING.  FOR SUNDAY AND MONDAY...UPPER FLOW GOES MORE ZONAL AND 
BRINGS IN PACIFIC AIR AND MILDER TEMPS. GFS SUGGESTING STRONG RETURN 
FLOW SETTING UP AS STRONG SURFACE LOW MOVES THROUGH SOUTHERN 
CANADA.  WILL START TO TREND TEMPS UP CONSIDERING CLIMATOLOGICAL 
BIASES.  GFS SUGGESTING SOME -RN POSSIBLE AHEAD OF H5 S/W MONDAY.  
LACK OF AVAILABLE MOISTURE WILL BE A PROBLEM...SO WILL HOLD OFF 
MENTIONING ANY PCPN FOR NOW.


IA...NONE.
IL...NONE.
MO...NONE.
DLF