FXUS63 KTOP 020513
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1113 PM CST TUE DEC 1 2009

.UPDATE...UPDATED FOR 06Z AVIATION.

&&

.AVIATION...VFR THROUGH THE TAF PD. CDFNT HAS PASS THROUGH THE TAF
SITES AND WIND WILL BEGIN TO PICK UP AGAIN THROUGH THE NIGHT.
MID/HIGH CLOUDS WILL COVER THE AREA INTO WED AFTERNOON WITH NO
RESTRICTIONS TO VIS EXPECTED. WIND WILL GUST TO AROUND 25 KTS ON
WED AS THE SURFACE GRADIENT TIGHTENS AND WIND WILL SUBSIDE AROUND
SUNSET.

SALLY
&&

PREV DISCUSSION... /ISSUED 236 PM CST TUE DEC 1 2009/ 

DISCUSSION...

LAST IN A SERIES OF ABOVE NORMAL DAYS TODAY...WITH SOUTHWEST WINDS 
AND TEMPERATURES IN THE UPPER 50S ACROSS MUCH OF THE AREA. SHORTWAVE 
TROF CONTINUES TO MOVE EASTWARD ACROSS THE NRN STATES...WITH 
TRAILING PIECE OF ENERGY USHERING A COLD FRONT SLOWLY ACROSS THE 
NORTHERN PLAINS. WEST TEXAS SYSTEM ALSO CONTINUES TO MOVE EASTWARD 
ACROSS THE SOUTH.

FRONT PROGGED TO MOVE INTO THE AREA LATE THIS EVENING. CLOUDS AND 
MOISTURE STREAM NORTHEASTWARD AHEAD OF THE SOUTHERN SYSTEM...AND 
WILL BE A CLOSE CALL FOR THE SOUTHEASTERN COUNTIES AS TO WHETHER 
ENOUGH MOISTURE CAN GET INTO THAT AREA FOR LIGHT SNOW OR FLURRIES 
BEFORE FRONT BRINGS DRIER AIR THROUGH THE BOUNDARY LAYER. WILL
MAKE LAST MINUTE CALL AS TO WHETHER TO LEAVE SLIVER OF POPS ACROSS
THE SE COUNTIES. AS FRONT MOVES SOUTHWARD WITH DEEPENING LONGWAVE
TROF...SFC PRESSURE GRADIENT INCREASES BETWEEN INCOMING NORTHERN
HIGH AND SOUTHERN LOW. WILL BE BREEZY TOMORROW WITH GUSTS 20 TO 35
MPH ACROSS THE AREA. TEMPERATURES MAKE LITTLE CHANGE AS STRONG CAA
CONTINUES THROUGHOUT THE DAY. A MIX TO 950 BRINGS HIGHS AT BEST
INTO THE UPPER 30S. WENT A BIT COOLER THAN GUIDANCE ESP ACROSS SE
COUNTIES.

67

LITTLE CHANGE IN FORECAST THINKING THROUGH THE EXTENDED. COLD PERIOD 
ANTICIPATED WITH BELOW NORMAL HIGH TEMPERATURES THROUGH THE WEEKEND. 
SFC COLD FRONT WILL DROP SOUTH INTO THE UPPER GOM WITH COLD SFC HIGH 
PRESSURE SETTLING INTO THE PLAINS THU AND FRI...WITH CONTINUED CAA 
WITH H85 TEMPS FALLING TO -13C OVER THE CWA BY FRI MORNING. READINGS 
WED NIGHT THROUGH FRI WILL SEE HIGHS IN THE 30S AND LOWS IN THE 
TEENS TO LOWER 20S. UPPER TROUGH WITH EMBEDDED SHORTWAVE TROUGHS 
ROTATING THROUGH WILL PROVIDE SOME WEAK ASCENT ACROSS THE NORTH ON 
THU. HOWEVER WITH DOWNGLIDE WITHIN THE SATURATED NEAR-SFC LAYER IN 
THE SNOW GROWTH ZONE...EXPECT TO SEE VERY LITTLE IF ANY SNOW 
FLURRIES ACROSS THE AREA. EXCEPTION MIGHT BE FAR NORTH CWA WHERE 
ASCENT THROUGH/ABOVE THE SATURATED LAYER IS GREATER. 
OVERALL...FORECAST THROUGH THE WEEKEND STILL LOOKS DRY. MODELS  
DIVERGE ON SPECIFICS BY EARLY NEXT WEEK...BUT SOME CONSENSUS EXISTS 
ON BRINGING AN UPPER TROUGH OFF THE PACIFIC COAST INTO THE PLAINS 
STATES MONDAY INTO TUESDAY. WITH THE ANTICIPATED DEEP ASCENT AND 
SOUTHERLY FETCH OF MOISTURE ADVECTED NORTHWARD IN ADVANCE OF THIS 
SYSTEM...SEEMS REASONABLE TO INTRODUCE SLIGHT CHANCE POPS FOR THIS 
PERIOD. VERTICAL TEMPERATURE PROFILE WOULD SUPPORT SNOW WITH INITIAL 
PRECIPITATION BEFORE UNCERTAINTY IN TEMPERATURE EVOLUTION EXISTS WITH 
A RA/SN MENTION THEREAFTER. NO OTHER NOTABLE CHANGES TO FORECAST 
PACKAGE.

BLAIR

&&

.TOP WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$