[LeArc] Forecast Discussion : MLI@ 2/10/03 4:40:42 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 101049
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
450 AM CST MON FEB 10 2003

RADARS HAVING A HARD TIME PICKING UP SOME OF THE SNOW TONIGHT..BUT 
WHERE REFLECTIVITIES ARE HIGHEST...VISIBILITIES HAVE BEEN DOWN TO A 
QUARTER OF A MILE...AND A QUICK TENTH OR SO OF ACCUMULATION HAS BEEN 
OBSERVED.  LATEST SURFACE ANALYSIS INDICATING THAT SURFACE FRONT 
DROPPING SOUTH ACROSS IA AT A GOOD CLIP...HAVING MOVED TO EXTEND 
FROM KSUX TO KDEH AS OF 07Z...FROM HAVING JUST ENTERED THE STATE 
FROM THE NORTHWEST AROUND 02Z.  VERY LITTLE BEHIND FRONT...ONLY 
FLURRIES BEING REPORTED...AND CLEARING LINE NOT TOO FAR NORTH OF 
IT...ACROSS SRN MN.  UPPER AIR ANALYSIS INDICATING THAT THE 700 AND 
500 MB TROUGH STILL TO THE NORTHWEST OF IA AT 00Z...BUT SLATER 
PROFILER INDICATING THAT TROUGH MOVING THROUGH AT 850 AND 700...WITH 
500MB ONLY JUST BEGINNING TO BACK.  NO GREAT PRESSURE RISE/FALL 
COUPLETS WITH THIS...SO DONT EXPECT FAST MOVEMENT.

MAIN CONCERNS THIS FORECAST INCLUDE PRECIP CHANCES THROUGH 
TUESDAY...AND TEMPS IN THE SAME PERIODS.

00Z MODELS APPEAR TO HAVE INITIALIZIED OK...WITH REASONABLY GOOD 
AGREEMENT AT 06Z. HOWEVER...BY 00Z TUES/MONDAY EVENING...THERE ARE 
SOME PRETTY SIGNIFICANT DIFFERENCES BETWEEN THE AVN AND THE 
ETA...UKMET...AND NGM. ONLY THE CANADIAN GEM IS AT ALL LIKE THE 
AVN...AND IT IS MUCH WEAKER.  AVN HAS A RELATIVELY STRONG SURFACE 
LOW THAT MOVES ACROSS CENTRAL MO MONDAY NIGHT...WHICH IS REALLY 
DIFFERENT FROM ALL THE OTHER MODELS...WITH A MUCH WEAKER 
FEATURE...FARTHER TO THE SOUTH.  FOR NOW...AM FAVORING THE MORE 
SOUTHERLY SOLUTIONS...WHICH AGREE BEST WITH GOING FCST AND FCST OF 
SURROUNDING OFFICES.  

TODAY...FRONT EXITS CWA TO THE SOUTHEAST IN THE MORNING.  WILL HANG 
ON TO MORNING FLURRIE IN THE SOUTHEAST...THOUGH THINK THAT JUST DRY 
WITH CLEARING CLOUDS WILL WORK FOR REMAINDER OF CWA.  TEMPS 
TRICKY...WITH STRONG CAA AFFECTING THE CWA.  THERE WILL BE MORNING 
HIGH IN THE MID TEENS ACROSS THE NORTH...THEN STEADY OR SLOWLY 
FALLING TEMPS.  CENTRAL PARTS OF THE CWA WILL HAVE MID-DAY HIGHS IN 
THE UPPER TEENS TO NEAR 20...THEN STEADY TEMPS.  FAR SOUTH MAY 
MANAGE TO HAVE AN AFTERNOON HIGH FROM 20 TO 25.  THIS IS FAIRLY 
CLOSE TO A BLEND OF THE ETA AND NGM MOS TEMPS...THOUGH FOR SOME 
REASON ETA MOS SEEMS TOO COOL.  WILL MONITOR TEMPS AS WE GET CLOSER 
TO ISSUANCE BEFORE FINAL TWEAKS GET MADE.

TONIGHT...DO NOT EXPECT MORE THAN FLURRIES BEFORE MIDNIGHT...WITH 
MAIN BAND OF SNOW ACROSS THE FAR SOUTHERN COUNTIES IN AN OVERRUNNING 
SORT OF SITUATION.  COLD SURFACE TEMPS COMBINED WITH ETA QPF AMOUNTS 
OF UP TO 6 TENTHS...WILL GO WITH SNOW AMOUNTS OF 1 TO 2 INCHES IN 
FAR SOUTH...TAPERING TO JUST A DUSTING NORTH.  TEMPS TO CONTINUE TO 
FALL...AND WILL STAY FAIRLY CLOSE TO AN ETA AND NGM MOS BLEND FOR 
MIN TEMPS. 

TUESDAY AND TUESDAY NIGHT...ANOTHER FAST WAVE MOVES THROUGH IN THE 
AFTERNOON/EARLY EVENING TIME FRAME.  ETA MOVEMENT OF THIS WAVE SEEMS 
TOO FAST...AND HAVE LINGERED PRECIP BEYOND ETA TIMING OF THIS 
EVENT.  MOVES TOO FAST TO PUT DOWN MUCH PRECIP...AND HAVE PUT HALF 
INCH OR LESS IN GRID FORECASTS.  FOR TEMPS...HAVE STUCK CLOSE TO 
NGM/ETA MOS COMBINATION FOR TUESDAY HIGHS.  TUESDAY NIGHT...WE WILL 
BE UNDER THE INFLUENCE OF A SURFACE RIDGE...ALL ZONES SHOULD HAVE 
SOME LIGHT SNOW COVER...AND LIGHT WINDS SHOULD ALLOW TEMPS TO REALLY 
DROP.  HAVE GONE BELOW ALL GUIDANCE...SIMILAR TO GOING FCST.  

WEDNESDAY IS MUCH QUIETER...WITH THE JET FINALLY SHIFTING EAST 
ENOUGH TO LEAVE THE CWA WITH JUST SOME CIRRUS...AND MODERATING 
TEMPS.  

DID NOT MAKE ANY CHANGES TO EXTENDED RANGE FCST FOR NOW.  FRIDAY 
SYSTEM LOOKING MORE INTERESTING...AND IF THIS TREND CONTINUES WE  
SHOULD BE ABLE TO GET SOME DECENT PRECIP ACROSS CWA.

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

$$
LRE