[LeArc] Forecast Discussion : MLI@ 2/4/03 2:40:32 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 042049
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
250 PM CST TUE FEB 4 2003

12Z MODELS APPEAR TO HAVE INITIALIZED RELATIVELY WELL...THOUGH 
NOTICED THAT SATELLITE...PROFILERS AND UA SOUNDINDS INDICATE THAT 
JET LEVEL WINDS OVER THE NM/AZ AREA ARE STRONGER THAN DEPICTED ON 
MODEL INITIALIZATIONS.  UNSURE AS TO WHETHER THIS WILL MAKE A 
DIFFERENCE IN THE IA FCST...BUT IS OF NOTE.  IN GENERAL...PREFER THE 
GFS SOLUTION FOR THE MOST PART.  THE ETA IS TOO SLOW WITH THE 
PROGRESSION OF THE FRONT FOR WEDNESDAY NIGHT AND THURSDAY...AND NGM 
AND ETA BOTH SEEM TOO DRY.

FOR TONIGHT...GREAT RADIATIONAL COOLING WILL BE KEPT FROM OCCURRING 
BY CLOUDS THAT SHOULD MOVE OVER CWA FROM THE WEST.  CURRENTLY THEY 
ARE OVER THE HIGH PLAINS...AND EVEN HAVE A FEW FLURRIES IN THEM.  
CIRRUS IS ALREADY MOVING IN...AND ONCE THE MID LEVEL CLOUDS MOVE IN 
THIS WILL BE AN EFFECTIVE HALT TO TEMPERATURE FALLS.  FWC TEMPS 
COOLER THAN OTHERS...AND DO NOT MOVE IN CLOUDS TIL WELL AFTER 
12Z...SO WILL GO WITH TEMPS BETWEEN WARMER GFS AND ETA MOS TEMPS.  
FLURRIES MIGHT BE POSSIBLE TOWARDS MORNING...BUT WILL NOT MENTION 
FOR NOW AND LATER SHIFTS CAN KEEP AN EYE OUT FOR THEM.

WEDNESDAY THE CLOUDS COME IN TO BLANKET THE AREA QUITE WELL...WITH 
LITTLE SUNSHINE TO WARM THINGS UP.  A WEAK SURFACE TROUGH WITH AN 
EVEN WEAKER SURFACE LOW CENTER MOVES TOWARDS THE AREA FROM THE 
NORTHWEST...WITH SOUTHWESTERLY FLOW INCREASING OVER THE DAY AHEAD OF 
THE TROUGH.  HAVE DECIDED TO HOLD OFF ON ANY PRECIP FOR THE 
DAYTIME.  HAVE KEPT TO COOLER GFS MOS TEMPS...ETA MUST BE HAVING 
PROBLEMS WITH THE SNOW COVER TO HAVE GONE WITH A 36 FOR A HIGH A 
BRL.  

WEDNESDAY NIGHT AND THURSDAY THERE IS A CHANCE FOR A FAIRLY NARROW 
BAND OF PRECIPITATION TO MOVE THROUGH THE AREA WITH AND/OR BEHIND 
THE SURFACE TROUGH AS IT SWEEPS ACROSS AREA...SO HAVE LOW CHANCE 
POPS FOR THE ENTIRE AREA AFTER MIDNIGHT WEDNESDAY NIGHT...AND ALSO 
FOR THURSDAY.  TIMING OF TROUGH IS FOR IT TO BE RIGHT OVER CWA 
AROUND 12Z...SO HAVE TO INCLUDE POPS IN BOTH PERIODS.  INSTABILITY 
SHOWERS MAY BE POSSIBLE LATE IN THE AFTERNOON WITH A 500MB COLD POOL 
IN THE VICINITY...SO HAVE DECIDED NOT TO LIMIT WORDING TO THE 
MORNING.  

THURSDAY NIGHT CLOUDS CLEAR OUT...AND IT COULD BE ANOTHER COLD ONE.  
GIVEN THE DIFFERENCES BETWEEN THE 1000-850MB THICKNESS...COLDER EVEN 
THAN TONIGHT/WEDNESDAY MORNING.  HAVE DECIDED TO LOWER TEMPS TO 
MATCH NEW GFS MOS LOW TEMPS.  FRIDAY TO BE SUNNY BUT COLD...LIKE 
TODAY. 

EXTENDED...SAT-TUE
ACTIVE WEATHER PATTERN...WITH LARGE SCALE UPPER LEVEL TROUGH OVER 
THE NORTHERN US...AND A SERIES OF CLIPPER LIKE SYSTEMS MOVING 
THROUGH THE FLOW.  THIS HAS RESULTED IN HAVING A CLIPPER MOVE 
THROUGH THE CWA NEARLY EACH DAY OF THE EXTENDED.  LOOKED FOR WAYS TO 
EXCLUDE SNOW FROM AT LEAST ONE OF THE DAYS...BUT COULD NOT.  

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

$$

LRE