FXUS63 KEAX 061125
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
525 AM CST SUN DEC 6 2009

...UPDATED AVIATION DISCUSSION...

.DISCUSSION...

FOCUS IS ON THE UPCOMING STORM SYSTEMS. FIRST CHANCE FOR PRECIP WILL 
BE DURING THE AFTERNOON AND OVERNIGHT HOURS...AS THE SHORTWAVE 
CURRENTLY OVER THE 4-CORNERS REGION MOVES EAST. SHOULD SEE SURFACE 
LOW OVER THE TEXAS AND OKLAHOMA PANHANDLES WITH INVERTED TROUGH 
STRETCHING NORTHEAST ACROSS EASTERN KANSAS...NORTHWEST MISSOURI INTO 
EASTERN IOWA GRADUALLY SLIDE EAST TONIGHT. ISENTROPIC UPGLIDE AHEAD 
OF THE APPROACHING SHORTWAVE WILL STRENGTHEN ACROSS THE FORECAST 
AREA THIS AFTERNOON AND EVENING. MOST OF THE FORECAST AREA WILL BE 
ON THE EAST SIDE OF THE INVERTED TROUGH. RELATIVELY WARM LOWER 
LEVELS AND PROGGED DRY LAYER ALOFT SHOULD PRECLUDE ICE CRYSTAL 
GROWTH. HAVE THEREFORE CONTINUED DRIZZLE FCST FOR THE AFTERNOON. 
NORTHWEST INTO NORTH CENTRAL MISSOURI AND FAR NORTHEAST KANSAS WILL 
BE ON THE WEST SIDE OF THE TROUGH AND THEREFORE SHOULD BE COLD 
ENOUGH FOR SNOW AND POSSIBLY FREEZING DRIZZLE. CHANCE OF DRIZZLE OR 
FREEZING DRIZZLE POSSIBLY MIXED WITH LIGHT SNOW OR FLURRIES STILL 
APPEARS POSSIBLE LATE TONIGHT...AS THE SYSTEM MOVES EAST AND COLDER 
AIR FILTERS IN.

EYES THEN TURN TO THE MONDAY NIGHT THROUGH WEDNESDAY TIMEFRAME. 
MODELS ARE COMING INTO BETTER AGREEMENT...TAKING THE NEXT SHORTWAVE 
OUT OF THE SOUTHWEST U.S. ACROSS THE CENTRAL AND SOUTHERN PLAINS 
TUESDAY AND NORTHEAST ACROSS SOUTHERN MISSOURI INTO SOUTHERN 
ILLINOIS BY WEDNESDAY. THIS SYSTEM WILL BE MUCH STRONGER...AIDED BY 
A MUCH STRONGER JET. TRACK OF HEAVY SNOW CURRENTLY LOOKS TO BE 
ACROSS NORTHEAST KANSAS ACROSS NORTHWEST INTO NORTH CENTRAL 
MISSOURI. ISENTROPIC LIFT IS EXPECTED TO DEVELOP AND FAIRLY QUICKLY 
SATURATE THE AIRMASS OVER KANSAS AND NORTHERN MISSOURI MONDAY NIGHT. 
SNOW MAY BEGIN TO ACCUMULATE AT THAT TIME. DEEP ISENTROPIC LIFT 
DEVELOPS ACROSS THE FORECAST AREA THROUGH THE DAY TUESDAY. THE 
POSSIBLE PROLONGED PERIOD OF SNOW ON TUESDAY IS EXPECTED TO BE 
MODERATE TO HEAVY AT TIMES. SPECIFIC HUMIDITIES MAY BE UPWARDS OF 3 
TO 4 G/KG ON TUESDAY.

AS THE ISENTROPIC LIFT LESSENS TUESDAY EVENING...DYNAMIC LIFT MOVES 
ACROSS THE AREA. MODELS INDICATE SIGNS OF A DEVELOPING DEFORMATION 
ZONE. SYSTEM APPEARS TO BE FAIRLY PROGRESSIVE AND SHOULD EXIT THE 
REGION WEDNESDAY MORNING. OF COURSE A DEVIATION IN THE TRACK OF THIS 
SYSTEM WILL HAVE A MAJOR AFFECT ON THE LOCATION OF THE BAND OF 
HEAVIEST SNOW. IN ADDITION...STRONG A STRONG PRESSURE GRADIENT 
DEVELOPS ACROSS THE AREA AS THE SYSTEM BEGINS TO PULL EAST. STRONG 
GUSTY NORTHERLY WINDS ARE EXPECTED. THESE WINDS WILL CREATE FURTHER 
DETERIORATING CONDITIONS.

DUE TO THE CONSISTENCY IN THE TRACK OF THIS SYSTEM WITH ONLY 
RELATIVE MINOR FLUCTUATIONS...AND THAT THIS SYSTEM HAS THE POTENTIAL 
TO PRODUCE WIDESPREAD MAJOR IMPACTS...HAVE DECIDED TO ISSUE A WINTER 
STORM WATCH AT THIS TIME. WATCH WILL BE GENERALLY ALONG AND NORTH OF 
A LINE FROM ATCHISON KANSAS TO MACON MISSOURI FROM 06Z TUESDAY 
THROUGH 12Z WEDNESDAY.

&&

.AVIATION...

VFR CONDITIONS EXPECTED THROUGH THIS AFTERNOON WITH THICK CIRRUS
COMMON ACROSS THE TAF SITES. CEILINGS ARE EXPECTED TO GRADUALLY
LOWER THROUGH THE DAY AND INTO THIS EVENING. INVERTED TROUGH
CURRENTLY STATIONED NEAR THE TERMINALS ATTM WILL PERSIST THROUGH THE
DAY WITH A WEAK SFC WAVE RIDING ALONG THE TROUGH BY THIS EVENING.
THIS WILL ALLOW FOR PRECIPITATION TO DEVELOP BY LATER THIS EVENING
AND TONIGHT. OVERALL NOT EXPECTED HEAVY ACCUMULATIONS AT THE
TERMINALS BUT A WAVE OF SNOWFALL OR DRIZZLE CAN BE EXPECTED
OVERNIGHT. 

DEROCHE

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER STORM WATCH FROM MONDAY EVENING THROUGH LATE TUESDAY 
     NIGHT FOR MOZ001>008-011>017-020>025.

KS...WINTER STORM WATCH FROM MONDAY EVENING THROUGH LATE TUESDAY 
     NIGHT FOR KSZ025-102.

&&

$$