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000
FXUS63 KLSX 101115
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
515 AM CST WED FEB 10 2010

.DISCUSSION...
/248 AM CST WED FEB 10 2010/

FLURRIES HAVE FINALLY ENDED OVER MOST OF THE CWA ATTM ALTHOUGH LOW
LEVEL CLOUD COVER CONTINUED TO BLANKET THE AREA BEHIND THE MID LEVEL
LOW AND ASSOCIATED SFC LOW OVER THE OH VALLEY REGION.  SHOULD SEE
GRADUAL CLEARING TDA WITH THE LATEST SATELLITE LOOP SHOWING PARTIAL
CLEARING ACROSS PARTS OF IA WHICH SHOULD WORK SWD INTO MO.  STG AND
GUSTY NWLY SFC WNDS SHOULD GRADUALLY WEAKEN AS THE TIGHT SFC
PRESSURE GRADIENT OVER THE CWA RELAXES AS THE SFC LOW MOVES FURTHER
E OF THE REGION AND THE N-S SFC RDG OVER THE PLAINS MOVES EWD INTO
MO.  SHOULD NOT BE MUCH OF A DIURNAL RISE IN TEMPS TDA WITH LOW
LEVEL CLOUD COVER DURING THE MRNG...CONTINUED WEAK CAA...AND SNOW
COVER.  TGT SHOULD BE THE COLDEST NGT DUE TO GOOD RADIATIONAL
COOLING UNDERNEATH THE SFC RDG AXIS WITH LGT SFC WNDS...A MOSTLY
CLEAR SKY...LOW SFC DWPTS AND SNOW COVER. TRANQUIL WEATHER SHOULD
CONTINUE ON THU ALTHOUGH MODEL RH FORECASTS BRING MORE CLOUDINESS
INTO THE REGION AS LOW-MID LEVEL WAA INCREASES OVER THE AREA. A
SRN STREAM SHRTWV WILL MOVE EWD ACROSS TX AND THE GULF COAST
REGION BUT ANY PRECIPITATION WITH THIS SYSTEM SHOULD REMAIN S OF
THE CWA. IT APPEARS THAT OUR NEXT CHANCE OF PRECIPITATION SHOULD
OCCUR FRI AND FRI NGT AS A NW FLOW SHRTWV AND ASSOCIATED WEAK SFC
REFLECTION DROP SEWD THRU THE AREA. THERE ARE SOME SLIGHT MODEL
DIFFERENCES MAINLY WITH TIMING. THE GFS MODEL APPEARS A LTL FAST
WHILE THE NAM MODEL SOLUTION LOOKS A LITTLE SLOW. PREFER THE ECMWF
AND CANADIAN GEM MODEL SOLUTIONS WHICH BRING SNOW TO THE NRN PTN
OF THE CWA ON FRI THEN SHIFT IT SEWD THROUGH THE SRN PTN OF THE
CWA FRI NGT. WITH LIMITED LOW LEVEL MOISTURE AND RELATIVELY QUICK
MOVEMENT OF THE SYSTEM THE SNOW AMOUNTS SHOULD BE LIGHT...MAYBE
ONE TO TWO INCHES AT MOST. THE HIGHEST QPF MAY OCCUR OVER THE NRN
AND ERN PTN OF THE CWA LEFT OF THE TRACK OF THE VORT CENTER AND
WEAK SFC LOW. AFTER THIS THE GFS AND ECMWF ARE FORECASTING A
STRONGER MID LEVEL LOW AND ASSOCIATED SFC LOW TO DROP SEWD THRU
THE AREA WHICH COULD BRING MORE SIGNIFICANT SNOW TO THE AREA
BEGINNING SAT AFTN AND CONTINUING UNTIL AT LEAST SUN MRNG. THE
CANADIAN MODEL AND THE NAM MODEL...OUT TO 18Z SAT...HAS A MUCH
DIFFERENT SOLUTION.

GKS

&&

.AVIATION...
/501 AM CST WED FEB 10 2010/

KSTL...MVFR CIGS FROM 1500-2000 FT WILL PREVAIL UNTIL AROUND
MIDDAY WHEN CLEARING FINALLY PUSHES IN FROM THE NORTH. CLEAR SKIES
WILL THEN PRETTY MUCH DOMINATE UNTIL MID MORNING ON THURSDAY WHEN
MID CLOUDS BEGIN SPREADING IN FROM THE WEST DUE TO WAA. AS FOR
WINDS...THE GUSTY NWLY WINDS WILL SUBSIDE THIS AFTERNOON AS THE
PRESSURE GRADIENT WEAKENS WITH HIGH PRESSURE SETTLING INTO EASTERN
MISSOURI ON THURSDAY MORNING.

FOR THE REMAINING AREA...MVFR CIGS FROM 1200-1800 FT PRETTY MUCH
DOMINATE WITH AN AREA OF IFR CIGS LOCATED FROM NORTH CENTRAL MO
INTO CENTRAL IA. THE BACK EDGE OF THE STRATUS CURRENTLY EXTENDS
FROM CENTRAL IL INTO CENTRAL IA AND IS PUSHING SOUTHWARD DUE TO
CYCLONIC FLOW ACROSS THE REGION. EXTRAPOLATION AND ANTICIPATED
EROSION SUGGESTS CLEARING LINE WILL CONTINUE TO PUSH SOUTHWARD
THROUGH KUIN AROUND MID MORNING AND AT KCOU TOWARD MIDDAY. NWLY
WINDS WILL SLOWLY DIMINISH TODAY AND WILL BE LIGHT TONIGHT.

GLASS

&&

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

$$

WFO LSX