FXUS63 KTOP 101723
AFDTOP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1123 AM CST THU DEC 10 2009
.UPDATE...
UPDATED FOR 18 UTC AVIATION FORECAST.
&&
.DISCUSSION...
SEE PREVIOUS DISCUSSION BELOW.
&&
.AVIATION...
VFR CONDITIONS WILL DOMINATE THE NEXT 24 HOURS. WILL SEE SOME HIGH
CLOUDS OVERNIGHT. SURFACE WINDS WILL BE 6 TO 10 KTS AND GENERALLY
SOUTHWESTERLY THIS AFTERNOON...BUT DROPPING OFF TO AROUND 2-3 KTS
OVERNIGHT TONIGHT.
BARJENBRUCH
&&
.PREV DISCUSSION... /ISSUED 322 AM CST THU DEC 10 2009/
DISCUSSION...
MAIN FORECAST PROBLEMS FOR THIS CYCLE ARE TEMPERATURES INTO THE
WEEKEND AND PRECIPITATION CHANCES THIS WEEKEND.
0Z UPPER AIR DATA SHOWING LONGWAVE TROF STILL ENTRENCHED OVER THE
NORTHERN AND CENTRAL CONUS. A WEAK SHORTWAVE WAS ROTATING SOUTHEAST
FROM THE NORTHERN ROCKIES WITH SOME ASSOCIATED HIGH CLOUDS EXITING
THE AREA EARLY THIS MORNING. WATER VAPOR IMAGERY SUGGESTS OTHER
SHORTWAVE TROFS AROUND 35N/140W AND 40N/160W. SURFACE HIGH PRESSURE
WAVE OVER CENTRAL OKLAHOMA AT 08Z WITH LIGHT WEST WINDS LOCALLY.
TEMPERATURES HAVE BOUNCED AROUND OVER THE PAST SEVERAL HOURS WITH
925MB WINDS OF 20-25KT PROVIDING SOME MIXING...WITH RESULTING WIND
CHILLS IN THE -20 TO 0 RANGE FOR THE MOST PART.
AFTER A VERY COLD NIGHT TONIGHT...TREND FOR THE NEXT FEW DAYS WILL
BE A WARMING ONE. UPPER HEIGHTS RISE CONSISTENTLY WITH STEADY LOW
LEVEL WARM AIR ADVECTION AS SURFACE WINDS BECOME MORE SOUTHERLY WITH
THE SLOW EXIT OF THE SURFACE RIDGE AND LEE TROFFING FROM FAST ZONAL
FLOW.
EXPECT A SLOW INCREASE IN WINDS THIS MORNING TO COMBINE WITH
THE COLD TEMPS TO KEEP WIND CHILL VALUES INTO ADVISORY LEVELS FOR AT
LEAST A FEW HOURS...AND GOING ADVISORY SEEMS TO HANDLE THE SITUATION
WELL. NEARLY FULL SUNSHINE WILL BE COUNTERACTED BY DEEP AND STILL
RATHER FRESH SNOWFALL TO KEEP TEMPS BELOW MOS NUMBERS. SHOULD SEE
SOME CIRRUS TONIGHT WHILE A WEAK LOW LEVEL RIDGE MOVES THROUGH. WILL
KEEP TEMPS BELOW MOS AGAIN...BUT APPEARS WIND CHILL VALUES WILL
REMAIN ABOVE ADVISORY RANGE. SOUTHERLY WINDS DEVELOPING ON FRIDAY
WILL BRING MOST LOW LEVEL PARCELS OFF OF SNOW FREE AREAS...BUT SNOW
WILL REMAIN IN PLACE. TRENDED CLOSER TO MOS NUMBERS HERE.
DEEPER WARM AIR ADVECTION WILL BEGIN TO BRING IN BETTER MOISTURE
FRIDAY NIGHT INTO SATURDAY NIGHT. MODELS STRUGGLE WITH THE TIMING OF
THE AFOREMENTIONED SHORTWAVES...AND THUS WITH THE DEPTH OF THE LIFT
AND MOISTURE. MODEL SOUNDINGS ARE SIMILAR WITH QUITE SATURATED LOW
LAYERS AND DEWPOINTS RISING INTO THE 30S BY SATURDAY AFTERNOON. WITH
QUESTIONS REMAINING IN THE MID AND UPPER LEVELS...WITH INTRODUCE
ONLY DRIZZLE FOR SATURDAY AND SATURDAY NIGHT. COULD ALSO SEE SOME
FOG OVER THE SNOW IF THE DEWPOINT PROGS VERIFY. WILL LEAVE
PRECIPITATION PLACEMENT UNTOUCHED FOR SUNDAY WITH UNCERTAINTY HIGH.
65
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.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
