FXUS63 KLSX 110504
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1104 PM CST THU DEC 10 2009

.UPDATE...
/952 PM CST THU DEC 10 2009/

HAVE ATTEMPTED TO MAKE A FEW TWEEKS TO TONIGHTS MINS. WINDS HAVE
STAYED UP IN N AREAS SLOWING THE TEMP DROP DURING THE EVENING...WHILE
TEMPS HAVE DROPPED A BIT FASTER THAN EXPECTED OVER PARTS OF THE E
OZARKS WHERE WINDS HAVE DECOUPLED DUE TO THE LIGHT GRADIENT OVER S
MO. BELIEVE THAT WITH THE VERY SLOW EASTWARD RETREAT OF THE SFC
RIDGE THIS N TO S MIXING TREND WON'T CHANGE TOO MUCH
OVERNIGHT...SO AS A RESULT HAVE UPPED TEMPS A DEGREE OR TWO IN
THE N.  ACROSS THE S THE TEMP FALL SHOULD LEVEL OFF DURING THE
PREDAWN HOURS...AND READINGS MAY EVEN CLIMB A FEW DEGREES...AS
HIGH LEVEL CLOUDINESS THAT HAS INCREASED FAIRLY RAPIDLY OVER S KS
AND N OK STREAMS E. 

TRUETT

&&

.DISCUSSION...
/341 PM CST THU DEC 10 2009/

SHORT TERM (TONIGHT THROUGH SAT)...1028MB SFC HIGH WAS CENTERED S OF 
THE CWA AT 20Z. WLY WINDS WILL GRADUALLY TURN SWLY TONIGHT AS THE 
HIGH CONTINUES SLIDING EWD. CLR SKIES...DIMINISHING WINDS...AND HIGH 
PRES NEARLY OVERHEAD WILL CREATE GOOD RADIATIONAL COOLING 
CONDITIONS...LEADING TO ANOTHER COLD NIGHT ACROSS THE BISTATE 
REGION. COLDEST TEMPS WILL BE ACROSS EXTREME NWRN COUNTIES WHERE 
SNOW COVER WILL AID RADIATIONAL COOLING PROCESSES. WENT AOB MOS
GUIDANCE WHICH RESULTS IN OVERNIGHT LOWS CONSISTENT WITH EXPECTED
TEMP DROP BASED ON LOCAL CIG/WIND CLIMATOLOGY. AS THE SFC HIGH
SHIFTS FARTHER E ON FRI NIGHT AND SAT...WINDS WILL TURN SLY AND
ACT TO MODERATE TEMPS WITH NEAR NORMAL HIGHS EXPECTED ON SAT AFTN.
MAINTAINED A NON-DIURNAL TEMP CURVE FOR FRI NIGHT DUE TO INCRSG SLY
RETURN FLOW. MODELS HAVE CONSISTENTLY DEPICTED A FAST MOVING
SHORTWAVE TROF OVER THE CENTRAL US FOR SAT NIGHT...THUS
MAINTAINED SCHC POPS FOR DZ/FZDZ BASED ON BUFKIT SOUNDINGS.

EXTENDED (SUN THROUGH THU)...PRIMARY FEATURE OF NOTE THIS PD IS
TROF THAT DVLPS OVER THE SRN PLAINS AND MOVES EWD SUN NIGHT AND
MON. ALTHOUGH THERE IS SOME MODEL DISAGREEMENT ON THE LOCATION OF
THE SFC LOW...APPEARS THAT SFC CDFNT WILL MOVE THROUGH THE CWA ON
MON NIGHT INTO TUE. ECMWF/GFS/GEM DEPICT SIMILAR FROPA TIMING BUT
DISAGREE ON INTENSITY OF COLD AIR BEHIND THE FNT WITH GEM/GFS
SHOWING MUCH COLDER AIR EXTENDING FARTHER SWD. GIVEN THAT THIS
SYSTEM IS STILL 5 DAYS OUT...MAINTAINED BELOW NORMAL TEMPS MON
NIGHT THROUGH WED AND WILL WAIT FOR FURTHER MODEL REFINEMENT
BEFORE BUYING INTO GEM/GFS SOLNS.

KANOFSKY

&&

.AVIATION...
/1056 PM CST THU DEC 10 2009/

FOR THE 06Z TAFS......SWLY SFC WNDS WILL CONTINUE LATE TGT WITH
THE SFC HI CURRENTLY CENTERED FROM ERN AR E-NE THRU CNTRL KY. AS
THE SFC RDG SHIFTS WELL SE OF THE AREA THE SFC WNDS WILL GRADUALLY
BACK AROUND TO A S-SWLY DIRECTION ON FRI...THEN TO A S-SELY
DIRECTION FRI NGT. THE ONLY CLOUDINESS EXPECTED IS A BAND OF HI
LVL CLOUDS WHICH WILL MOVE THRU COU...STL AND SUS LATE TGT AND
EARLY FRI MRNG.

GKS

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

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