FXUS63 KLSX 270942
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
342 AM CST FRI NOV 27 2009

.DISCUSSION...
/333 AM CST FRI NOV 27 2009/

AFTER A COLD START EARLY THIS MRNG TEMPERATURES SHOULD WARM UP 
RAPIDLY AS THE SFC RDG MOVES E OF THE CWA AND SFC WNDS BECOMES SLY.  
A MID-UPPER LEVEL RIDGE OVER THE ROCKYS AND PLAINS WILL BE MOVING
SLOWLY EWD INTO THE CWA WITH RISING MID-UPPER LEVEL HEIGHTS. THERE
WILL BE PLENTY OF SOLAR INSOLATION WITH ONLY A LITTLE CIRRUS
DROPPING SEWD THRU THE CWA TDA. WILL FORECAST WELL ABOVE
PERSISTENCE FOR MAX TEMPS TDA. THIS WARMING TREND WILL CONTINUE
THROUGH SAT NGT WITH CONTINUED LOW-MID LEVEL WAA OVER THE AREA.
SATURDAY WILL BE THE WARMEST DAY...WELL ABOVE NORMAL...WITH 850
MB TEMPERATURES OF 11-12 DEGREES C ACROSS THE CWA AND ONLY CIRRUS
CLOUDS TO LIMIT DIURNAL HEATING. THE NEXT CHANCE OF RAIN WILL
OCCUR SUNDAY AND SUNDAY NIGHT AS A MID-UPR LEVEL TROF DROPS SEWD
THRU THE NRN PLAINS AND GREAT LAKES REGIONS SENDING A CDFNT SEWD
THRU THE CWA SAT NGT AND SUN. INITIALLY AS THIS CDFNT DROPS SEWD
THRU THE NWRN PORTION OF THE CWA SAT NGT IT APPEARS THAT THE
MOISTURE WILL BE QUITE LIMITED BUT THIS FRONT SHOULD INTERCEPT
BETTER LOW-MID LEVEL MOISTURE ON SUN AS IT MOVES SEWD THRU THE
SERN HALF OF THE CWA. ALL THE MODELS GENERATE POST FRONTAL
PRECIPITATION ACROSS THE SERN HALF OF THE CWA SUN NGT. THE GFS
MODEL IS THE MOST PROGRESSIVE WITH THE PRECIPITATION FORECAST
WHILE THE ECMWF AND NAM ARE A LITTLE SLOWER IN SHIFTING THE RAIN
SEWD THRU THE CWA SUN NGT. THE NAM MODEL GENERATES A WEAK SFC WAVE
ALONG THE FRONT WHICH SLOWS THE SEWD PUSH OF THE PRECIPITATION.
COLDER AIR WILL BE FILTERING SEWD INTO THE CWA SUN NGT BEHIND THE
CDFNT BUT AS IS TYPICAL THE RAIN SHOULD END BY THE TIME THE
FREEZING OR NEAR FREEZING SFC TEMPERATURES ARRIVE. MONDAY AND
MONDAY NIGHT WILL BE QUITE A BIT COLDER ALTHOUGH NOT FAR OFF FROM
CLIMATOLOGICAL NORMALS FOR LATE NOVEMBER/EARLY DECEMBER.

GKS

&&

.AVIATION...
/1047 PM CST THU NOV 26 2009/

FOR THE 06Z TAFS...MINOR IF ANY CHANGES TO PREV FORECAST. ONLY
CLOUDS EXPECTED WILL BE CI. WINDS WILL GRADUALLY BACK TO
EVENTUALLY BECOME SLY BY FRI AFTERNOON. WINDS WILL BE VEER
SLIGHTLY FRI EVE INTO THE OVERNIGHT HOURS. BASED ON LATEST MODEL
GUIDE...LLWS MAY BE POSS OVERNIGHT FRI INTO SAT MORNING. 

TILLY

&&

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

$$

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