071 
FXUS63 KLSX 130947
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
347 AM CST WED JAN 13 2010

.DISCUSSION...
/307 AM CST WED JAN 13 2010/
MAIN FORECAST CONCERN FOR THE NEXT 7 DAYS WILL BE TEMPS AND CHANCE
OF DZ AND FG TOMORROW AND TOMORROW NIGHT. 

MDLS AGREE WELL WITH UPA RIDGE CONTINUING TO BUILD EWD THRU
TOMORROW. S/W OVER TX IS PROGD TO BECOME ABSORBED INTO THE ZONAL
PATTERN ON FRI AS IT MOVES NWD TWD THE CWA. FORECAST REMAINS DRY
THRU THE END OF THE FORECAST PERIOD. 

HOWEVER...MDLS PROG THE TROF ALONG THE WRN COAST THIS MORNING TO
UNDERGO LEE CYCLOGENESIS AND DIG INTO THE SRN PLAINS AND INTO
MEXICO LATE THIS WEEK. GEFS MEAN/ECMWF/GEM AGREE WELL WITH THIS
UPA LOW LIFTING NEWD ON SAT AND TRAVELING ALONG THE SRN US. THE
DETERMINISTIC GFS HAS A DRASTICALLY DIFFERENT SOLN AND HAVE LITTLE
CONFIDENCE WITH THAT SOLN AND HAVE TRENDED TWD THE OTHER GUIDANCE.
THIS SOLN WILL JUST BRUSH THE SERN CWA WITH EITHER RA OR SN. FOR
NOW...HAVE KEPT SILENT 20 POPS IN THE FORECAST AS MDLS CONTINUE TO
SHOW LITTLE RUN TO RUN CONTINUITY.

TEMPS TODAY WILL BE AFFECTED BY WAA AND SNOW PACK. A BLEND OF
MAV/MET MOS VERIFIED THE BEST ON MON UNDER SIMILAR CIRCUMSTANCES
AND HAVE THEREFORE GONE WITH A SIMILAR SOLN FOR TODAY. 

WAA TODAY IS EXPECTED TO AID IN SN MELT...WHICH SHUD MOISTEN THE
BOUNDARY LAYER AS MIXING WILL BE MINIMAL TODAY. WITH THE ADDED
MOISTURE...STRATUS IS EXPECTED TO DEVELOP TONIGHT WITH FG ALSO
BEING POSSIBLE. THE STRATUS WILL BE JUST ON THE WARM SIDE OF A
WEAK COLD FRONT APPROACHING THE CWA TOMORROW NIGHT AND FRI. WITH
THE WEAK LIFT ASSOC WITH THIS FRONT...HAVE SILENT 20 POPS GOING
WITH A SLIGHT CHANCE OF DZ AS THE FRONT APPROACHES...THEN STALLS
ACROSS THE CWA ON FRI. 

THIS STRATUS DECK IS EXPECTED TO REMAIN OVER THE CWA TOMORROW.
HAVE THEREFORE TRENDED TEMPS TOMORROW TWD THE COOLER MOS AND TWD
WARMER MOS TONIGHT AND TOMORROW NIGHT. THE FRONT WILL NOT HAVE
MUCH OF AN IMPACT ON TEMPS FOR FRI. AGAIN...TRENDED TWD A BLEND OF
MET/MAV MOS FOR FRI AS MUCH OF THE AREA WILL REMAIN UNDER CLOUD
COVER. LITTLE CHANGES WERE MADE TO THE PREV TEMP FORECAST FOR SAT
AND BEYOND. 


TILLY

&&

.AVIATION...
/1053 PM CST TUE JAN 12 2010/

FOR THE 06Z TAFS...STUBBORN STRATUS CLOUD BAND HAS FINALLY
ADVECTED N OF UIN. SOME LOCALIZED FOG HAS DEVELOPED THIS EVNG
ALTHOUGH WITH INCREASING SLY SFC WNDS AT UIN AND COU...PLUS MODELS
INDICATING SOME DRYING OF THE BOUNDARY LAYER LATE TGT...NOT
CONFIDENT THAT VSBYS WILL DETERIORATE LATE TGT AT UIN AND COU. THE
SLY SFC WNDS SHOULD CONTINUE TO GRADUALLY INCREASE IN UIN AND COU
LATE TGT AND WED MRNG AS THE SFC RDG SHIFTS FURTHER SE OF THE CWA
AND THE SFC PRESSURE GRADIENT TIGHTENS LATE TGT AND WED. WILL
INCLUDE LIGHT FOG IN STL/SUS LATE TGT AND EARLY WED MRNG AS THE
SFC WNDS WILL REMAIN RELATIVELY LIGHT...CLOSER TO THE SFC RDG
AXIS...TIL AFTER SUNRISE WED MRNG. SLY SFC WNDS SHOULD PICK UP TO
AT LEAST 10 KTS BY WED AFTN WITH ONLY A LITTLE CIRRUS CLOUDINESS.

GKS

&&

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

$$

WFO LSX