FXUS63 KEAX 120900
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
300 AM CST SAT DEC 12 2009

.DISCUSSION...

IN THE SHORT TERM PORTIONS OF THE FCST...PRIMARY CONCERNS REMAIN ON 
TEMPS AS WELL AS LIGHT QPF POTENTIAL TODAY AND TONIGHT. EARLY THIS 
MORNING...ISENTROPIC LIFT GENERATED A BAND OF LOW-LVL STRATUS WHICH 
HAS LIFTED NORTH THROUGH THE REGION. THIS STRATUS HAS TEMPORARILY
JUMPED SFC TEMPS BACK TOWARDS THE FREEZING MARK. THIS MOISTURE IS
BRING PULLED NORTHWARD AHEAD OF A FAST MOVING S/W TROUGH VISIBLE IN
WV IMAGERY OVER THE OK PANHANDLE. FOR TODAY...SOUNDINGS CONTINUE TO
INDICATE RAPID SATURATION OF THE LOWER-LVLS OF THE ATMOSPHERIC COLUMN
BY THE LATE MORNING HOURS. IR IMAGERY SHOWS THIS MOISTURE FIELD
ALREADY ADVECTING NORTHWARD INTO SERN KS AND SOUTHERN MO ON THE WINGS
OF 30-35 KNOT 925MB WINDS. AS ISENTROPIC LIFT INCREASES AHEAD OF THE
WEAK S/W LATE THIS MORNING...SOUNDINGS ARE SUPPORTIVE OF DRIZZLE
DEVELOPING BY 18Z AND LIFTING NORTHWARD THROUGH THE AREA. SATURATION
UP TO 825 MB AND MODEST TURBULENT MIXING AT THE TOP OF THE SATURATED
LAYER MAY PROMOTE MODERATE DRIZZLE AT TIMES. QPF SHOULD BE
LIGHT...BUT COULD SEE A FEW AREAS PICK UP A HUNDREDTH OR TWO OF
PRECIP. SFC TEMPS WILL START OUT WARMER THAN EXPECTED...AND MAY
QUICKLY JUMP ABOVE FREEZING AFTER 12Z. HOWEVER...THICK CLOUD COVER
WILL LIMIT THE UPWARDS CLIMBING OF TEMPS TO THE MIDDLE AND UPR 30S.
THERE MAY BE SOME CONCERN OVER NORTHERN MO IN REGARDS TO FREEZING
DRIZZLE...HOWEVER FEEL THAT BY TIME SATURATION OCCURS MANY AREAS WILL
HAVE ALREADY ARRIVED TO 32-34 DEGREES.

SATURDAY NIGHT...AS THE WEAK S/W TROUGH MOVES THROUGH IT WILL NUDGE 
A WEAK SFC COLD FRONT INTO THE NWERN THIRD OF THE CWA AFTER MIDNIGHT.
AHEAD OF THIS FRONT...SWLY SFC WINDS ALONG WITH DEW POINTS IN THE
LOWER 30S WILL ADVECT OVER THE REMNANT SNOWPACK TO OUR SW. WHILE
VERTICAL DEPTH OF MOISTURE PROFILE DISAPPEARS...SOUNDINGS SUGGEST A
PERIOD OF ADVECTION FOG. SREF PROBABILITIES SUGGEST VISIBILITIES
LESS THAN 3 MILES...WITH HIGHER THAN NORMAL PROBABILITIES/SIGNALS OF
DENSE FOG AHEAD OF THE SFC FRONT. TEMPS IN THE SERN PORTIONS OF THE CWA
SHOULD REMAIN NEAR OR ABOVE FREEZING. HOWEVER LATEST GUIDANCE
SUGGESTS COLDER AIR WILL FILTER INTO THE NORTHERN HALF OF THE CWA BY
DAYBREAK SUNDAY AND RESULTANT TEMPS MAY REMAIN BLO FREEZING.

FOR SUNDAY...THIS WEAK FRONT WILL STALL ACROSS THE CWA QUICKLY
TRANSITIONING INTO A WARM FRONT BY SUNDAY AFTN AHEAD OF YET ANOTHER
FAST MOVING S/W. EXPECTING THE NORTHERN PORTIONS OF THE CWA TO BE
MUCH COLDER THAN AREAS FURTHER SOUTH...WITH LOCATIONS SOUTH OF THIS
BOUNDARY WARMING INTO THE LOWER TO MIDDLE 40S. SUNDAY NIGHT REMAINS
TRICKY AS ISENTROPIC LIFT BEGINS TO INCREASE AHEAD OF THE NEXT WAVE.
THIS WAVE WILL BE SLIGHTLY STRONGER THAN SAT...AND IS EXPECTED TO
GENERATE A STRONGER SFC PRESENCE. THIS BEING SAID...LOW-LVL WAA AHEAD
OF THIS DEVELOPING SFC LOW TO OUR WEST SHOULD MAINTAIN RATHER WARM
CONDITIONS OVERNIGHT SUN WITH LITTLE DROP OFF IN OVERNIGHT LOWS
EXPECTED. IN ADDITION...THE POTENTIAL FOR ADDITIONAL FOG DEVELOPMENT
OVER AREAS WITH LINGERING SNOW PACK AND SFC MOISTURE SEEMS PROBABLE.
THE DEPTH OF THE LOW-LVL MOISTURE MAY BE THICK ENOUGH TO PRODUCE
LIGHT FREEZING DRIZZLE OR FREEZING FOG IN NORTHERN MO.

BEHIND THIS SECOND S/W WILL BE A POTENT...BUT SHALLOW...CANADIAN AIR
MASS WHICH WILL BEGIN TO SURGE SE BY MONDAY MORNING. HIGH TEMPS ARE
EXPECTED TO TAKE PLACE EARLY IN THE MORNING...WITH TEMPS FALLING BY
MID-DAY AS COLD AIR SURGES IN. EXPECT RATHER COLD TEMPS MON NIGHT
THROUGH TUE NIGHT...WITH HIGHS ON TUE STRUGGLING TO REACH THE 20S.

DUX

&&

.AVIATION...

FOR THE 06Z TAFS...BKN/OVC VFR CEILINGS HAVE OVERSPREAD THE 
TERMINALS AND SHOULD HANG AROUND THROUGH THE NIGHT. BETTER MOISTURE 
AND DEEPER ISENTROPIC LIFT STILL LOOKS LIKE IT WILL ARRIVE MID/LATE 
SATURDAY MORNING. THIS SHOULD RESULT IN MVFR CEILINGS. BUFR 
SOUNDINGS STILL SUPPORT AREAS OF DRIZZLE AND MVFR FOG DEVELOPING 
OVER EASTERN KS/WESTERN MO DURING THE MID TO LATE AFTERNOON HOURS. 
THIS SHOULD EVENTUALLY LOWER CEILINGS INTO THE IFR CATEGORY WITH 
INTERMITTENT DRIZZLE. TEMPERATURES AT KMCI/KMKC SHOULD REMAIN ABOVE 
FREEZING DURING THIS PERIOD SO ANY PRECIPITATION SHOULD REMAIN ALL 
LIQUID. THERE IS SOME CONCERN THAT AIR TEMPERATURES AT KSTJ COULD 
DROP JUST BELOW FREEZING SATURDAY EVENING TO RESULT IN FREEZING 
DRIZZLE. SINCE CONFIDENCE IS NOT HIGH WILL LEAVE PRECIPITATION TYPE 
AS ALL LIQUID.

MJ

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$