FXUS63 KTOP 071813 AAA
AFDTOP

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TOPEKA KS
1213 PM CST MON DEC 7 2009

.UPDATE...

UPDATED FOR THE 18 UTC TAF ISSUANCE.

&&

.DISCUSSION...

SEE PREVIOUS DISCUSSION.

&&

.AVIATION...

PROFILERS/SATELLITE AND SFC OBS SUPPORT TEMPORARY BREAK IN THE
MVFR CIGS EARLY THIS AFTERNOON BEFORE VEERING LLVL WINDS PUSH
SOLID STRATUS DECK BACK ACROSS THE TAF SITES BY 20Z...WHICH 
MAY ALREADY BE UNDERWAY TO THE SOUTH LOOKING AT MOST RECENT
VISIBLE FRAME ON SATELLITE. AS NEXT STORM SYSTEM APPROACHES...WILL 
CONTINUE TREND OF STEADILY LOWERING CIGS INTO THE EVENING...THEN 
BEGIN MVFR VSBYS IN LIGHT SNOW AS ISENTROPIC LIFT/WAA INCREASE.
WITH LIFT INCREASING OVERNIGHT AND DEEPER SATURATION WILL LOWER
CIGS AND VSBYS TO IFR TOWARDS 09Z...THEN LIFR TO VLIFR IN SNOW IN
THE 12-15Z TIMEFRAME ON THROUGH 18Z. WILL ALSO GRADUALLY INCREASE
WINDS THROUGH THE TAF PERIOD. LIFR/VLIFR CONDITIONS SHOULD PERSIST
BEYOND 18Z ACROSS THE TAF SITES.

&&

PREV DISCUSSION... /ISSUED 301 AM CST MON DEC 7 2009/

DISCUSSION...

.DEVELOPING WINTER STORM STILL ON TRACK FOR MONDAY NIGHT INTO
TUESDAY NIGHT...

UPPER SHORTWAVE TROF HAS LIFTED INTO MISSOURI...WITH PRECIP
ENDING ACROSS THE AREA. COLD AIR SPILLING IN BEHIND...WITH CLOUDS
OVER OUR AREA TEMPORARILY SLOWING THE FALL. REPORTS OF 1 TO 3
INCHES OF SNOW IN WASHINGTON AND REPUBLIC COUNTY WITH DIMINISHING
AMTS ELSEWHERE.

EXPECT TEMPS TO CLIMB VERY LITTLE TODAY AS HIGH PRESSURE SLIDES
INTO THE STATE. HIGHS AROUND 20 OVER THE SNOW TO THE MID 30S
SOUTHEAST.

MAIN STORM SYSTEM STILL ON A SIMILAR TRACK FROM PREVIOUS
FORECASTS. ISENTROPIC LIFT SHOULD START TO PRODUCE LIGHT SNOW IN
FAR WESTERN COUNTIES IN THE EVENING HOURS...AND WILL THEREFORE GO
AHEAD AND START THE WARNING WITH THIS ISSUANCE FOR THIS AREA AT
THAT TIME. MAY GET A BRIEF PERIOD OF FREEZING DRIZZLE IN SOUTHWEST
AND SOUTHEAST COUNTIES...BUT EXPECT TO CHANGE OVER TO SNOW QUICKLY
AS COLUMN IS FAST TO SATURATE. AS STRONG UPPER JET PUNCHES ACROSS
THE FOUR CORNERS AREA...EXPECT THIS TO ENHANCE SNOWFALL AFTER
MIDNIGHT ACROSS THE AREA AND COULD SEE A QUICK FEW INCHES CENTERED
AROUND THE I70 CORRIDOR THEN. PROLONGED PERIOD OF LIFT ACROSS THE
ENTIRE AREA CONTINUES THROUGH 18Z...AND THEN THE FORECAST SOUTH OF
INTERSTATE 70 BECOMES COMPLICATED BY INCREASING WARM AIR IN THE
LOW LEVELS FOR THE AFTERNOON. SO AFTER AN OVERNIGHT PERIOD OF A
FEW INCHES OF SNOW...EXPECT AREAS ALONG I70 AND I35 CORRIDOR TO
CHANGE BACK OVER TO A RAIN SNOW MIX...OR EVEN A RAIN SNOW SLEET
MIX...FOR A TIME IN THE AFTERNOON AFTER WHICH THE COLD AIR PLUNGES
SOUTH AND SWITCHES BACK OVER TO SNOW AGAIN. THINKING THIS WILL
LIMIT AMOUNTS TO ADVISORY NUMBERS OR LESS FOR THIS AREA. AS FOR
AREAS TO THE NORTH...MANY HOURS OF UPGLIDE SHOULD RESULT IN A
STEADY INCREASE IN SNOW AMOUNTS...WITH AFOREMENTIONED BURST IN THE
6-12Z TUESDAY TIME FRAME...AND THEN EXPECTING FURTHER ENHANCEMENT
AROUND THE 0Z WED HOUR. SEE MANY LIFTING MECHANISMS COMING
TOGETHER INCLUDING BAND OF FRONTOGENESIS AND ISENTROPIC LIFT...AS
WELL AS ENERGY FROM THE PVA FROM THE SHORTWAVE TROF ITSELF...AND
ASSOCIATED DEFORMATION ZONE IN THE WIND FIELD. LOOKS LIKE A REAL
MESS ACROSS NORTHEAST KANSAS AROUND 0Z WED /6PM TUESDAY/ WHICH
WILL BODE VERY POORLY FOR ANYONE OUT ON THE ROADWAYS AROUND THIS
TIME...PARTICULARLY FOR AREAS NORTH OF INTERSTATE 70.

WILL CONTINUE TO CARRY THE WATCH FOR THE EASTERN COUNTIES AND LET
DAY SHIFT UPGRADE...AS DO NOT SEE SNOW STARTING UNTIL AROUND THE
MIDNIGHT HOUR FOR THOSE AREAS. ALSO WILL LET DAY SHIFT EVALUATE
SOUTHERN COUNTIES FOR POSSIBLE ADVISORIES FOR TUESDAY MORNING.

MODELS ALSO STILL DEPICT SUSTAINED WINDS OF 20-30 MPH ACROSS THE
AREA INTO 12Z WEDNESDAY...AND EXPECT THIS TO CAUSE BLOWING OF
FALLING SNOW AND DRIFTING OF FALLEN SNOW BECOMING MORE SIGNIFICANT
FARTHER NORTH WHERE PRECIP FALLS AS ALL SNOW. 

MADE VERY FEW CHANGES TO WEDNESDAY GRIDS EXCEPT TO SAY ITS COLD.
SINGLE DIGIT LOWS AND HIGHS IN THE TEENS FOR MUCH OF THE AREA. 67

&&

.TOP WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING FROM 6 PM MONDAY 
TO 6 AM WEDNESDAY FOR KSZ008-KSZ009-KSZ020-KSZ021-KSZ034-KSZ035.

WINTER STORM WATCH FROM MIDNIGHT TUESDAY TO 6 AM WEDNESDAY FOR 
KSZ010-KSZ011-KSZ012-KSZ022-KSZ023-KSZ024-KSZ026-KSZ036-KSZ038-
KSZ039.

&&

$$

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