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000
FXUS63 KLSX 100857
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
257 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...
/1128 PM CST TUE FEB 9 2010/

KSTL...CIGS CONTINUE TO BE THE REAL QUESTION FOR THE REST OF THE
NIGHT. STILL SEEING CIGS BTWN 1500-1900FT ACROSS PORTIONS OF
NORTHEAST MO/WEST CENTRAL IL WHICH COULD ROTATE DOWN ACROSS THE
TERMINAL. BUT MY CONFIDENCE LEVEL IS NOT HIGH ENOUGH TO INCLUDE
IN THE TAF AT THIS TIME. ALSO...TIMING THE EVENTUAL SCATTERING OUT
WEDNESDAY MORNING IS TOUGH. MOVED IT BACK A FEW HOURS SINCE THE
CLEARING LINE IS NOT MOVING VERY FAST THRU SOUTHEAST IOWA...AND
THIS MAY YET BE TOO OPTIMISTIC.

FOR THE REMAINING AREA...SCATTERED LIGHT SNOW OR FLURRIES WILL
CONTINUE...MAINLY ALONG AND SOUTH OF THE I-70 CORRIDOR FOR MUCH OF
THE REST OF THE NIGHT. VSBYS COULD BRIEFLY DIP INTO MVFR RANGE IN
SOUTHEAST MO OVER THE NEXT FEW HOURS...BUT VFR VSBYS SHOULD
PREVAIL. NOTICED A DIP INTO IFR CIG RANGE AT KUUV THIS HOUR. THIS
IS THE ONLY IFR CIG I`VE NOTICED IN THE BI-STATE REGION ALL
NIGHT...SO I THINK THIS IS ASSOCIATED WITH AN ISOLATED HEAVIER SNOW
SHOWER AND SHOULD BE VERY BRIEF. MAJORITY OF THE AREA SHOULD
PREVAIL 2000-3000FT CIGS WITH INTERMITTENT DIPS TO BETWEEN
1500-1900FT ESPECIALLY OVER NORTHEAST MO/WEST CENTRAL IL UNTIL THE
CIGS SCATTER OUT. WEST-NORTHWEST WINDS WILL BE GRADUALLY CALMING
DOWN THRU THE FORECAST PERIOD.

CARNEY

&&

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

$$

WFO LSX