000
FXUS63 KEAX 201148
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
538 AM CST THU NOV 20 2008
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
FORECAST AREA WILL BE UNDER STRONG COLD AIR ADVECTION TODAY AS A
STRONG 1050 HIGH CENTERED IN CENTRAL CANADA...PLUNGES SOUTH INTO THE
CENTRAL U.S. BY 12Z FRIDAY. A THIN LAYER OF MOISTURE ACCOMPANYING
THIS SURGE OF COLDER AIR HAS PRODUCED A STRATUS DECK OVER THE UPPER
MIDWEST THAT HAS SPREAD INTO THE FORECAST AREA OVERNIGHT. MODELS
HAVING TROUBLE CAPTURING THIS MOISTURE SINCE IT IS SO THIN...BUT
JUDGING FROM THE NAM COND PRESS DEFICITS...THE INITIAL BAND OF
CLOUDS CURRENTLY IN THE REGION SHOULD CONTINUE TO DROP SOUTH OUT OF
THE AREA THIS MORNING AS SOME MOISTURE AROUND THE H7 LEVEL MOVES
OVER TOP...SO MAY NOT SEE MUCH SUNSHINE THIS MORNING. THIS AFTERNOON
THOUGH...MAY SEE SOME SC FORM BUT SHOULD BE ENOUGH HOLES TO ALLOW
THE SUNSHINE TO WARM THE AIRMASS A BIT DESPITE THE STRONG CAA.
STILL...WILL LEAN TOWARD THE COLDER MET GUIDANCE GIVEN TEMPERATURE
PROFILES UPSTREAM THIS MORNING. ALSO...WILL REMOVE MENTION OF
FLURRIES WE HAD GOING IN NORTHEAST PORTION OF THE FORECAST AREA WITH
THE THIN LOW LEVEL MOISTURE.
FOR TONIGHT...WITH THE SURFACE HIGH AXIS SLIDING INTO EASTERN KANSAS
AND NORTHWEST MISSOURI...AND SOME VERY DRY AIR MOVING INTO THE
REGION...SHOULD SEE A GOOD RADIATIONAL COOLING SET UP. GIVEN STILL
SOME WARMTH IN THE GROUND AND EFFECTS OF THE CITY...HESITATE TO GO
AS COLD AS THE MET NUMBERS FOR THE KC METRO AREA...BUT WILL TREND
TOWARD THEM FOR REST OF AREA...ESPECIALLY FOR THE MORE LOW LYING
SPOTS.
HAVE NOT MADE ANY SIGNIFICANT CHANGES TO THE REST OF THE FORECAST.
THE ONE THING TO WATCH WILL BE A FAST MOVING SHORT WAVE TROUGH
CURRENTLY OF THE PACIFIC NORTHWEST COAST...WHICH WILL MOVE INTO THE
DAKOTAS BY FRIDAY EVENING...AND INTO IOWA BY 12Z SATURDAY. THIS
SYSTEM WILL BE PRETTY MOISTURE STARVED AS THERE WILL BE NO TIME FOR
ANY RETURN FLOW TO BRING MOISTURE BACK INTO THE FORECAST AREA BEFORE
ITS ARRIVAL. THE ECMWF HINTS THAT SOME LIGHT PRECIPITATION MAY OCCUR
IN NORTHERN MISSOURI BY 12Z SATURDAY AS A JET MAX AND DIFFLUENT
UPPER FLOW AFFECTS THE REGION...BUT GIVEN THE LACK OF LOW LEVEL
MOISTURE...WILL OPT FOR THE DRY FORECAST AT THIS POINT.
FOR SUNDAY...WITH THE SURFACE RIDGE EAST OF THE REGION...A RETURN
FLOW MAY BE ABLE TO BRING ENOUGH LOW LEVEL MOISTURE BACK TO THE
REGION TO SUPPORT RAIN SHOWERS AS YET ANOTHER SHORT WAVE TROUGH
DEVELOPS OVER THE NORTH CENTRAL PART OF THE COUNTRY. WILL LEAVE THE
SLIGHT CHANCE POPS THAT THE PREVIOUS FORECAST HAD GOING ACROSS THE
SOUTHEAST HALF OF THE FORECAST AREA...ALTHOUGH ONSET OF THESE
SHOWERS MAY BE DELAYED UNTIL SUNDAY EVENING AS THE BETTER MOISTURE
MAY NOT ARRIVE UNTIL THEN. ANOTHER SURGE OF COLDER AIR WILL ARRIVE
THE FIRST OF THE WEEK IN THE WAKE OF SUNDAY SHORT WAVE.
PC
&&
.AVIATION...
FOR THE 12Z TAFS...MVFR CLOUD DECK THAT SPREAD ACROSS THE TERMINAL
OVERNIGHT IS ON THE CUSP OF EXITING THE LAST OF OUR THREE TERMINALS
THIS MORNING. CLOUD COVER LEFT BEHIND IS OF THE VFR VERITY WITH
HEIGHTS IN THE 10KFT RANGE. MIGHT GET A SCATTERED CU DECK LATE THIS
MORNING AND AFTERNOON AS BOUNDARY LAYER MIXING OCCUR...BUT MODEL
SOUNDINGS INDICATE THAT ANY CLOUD DECK THAT FORMS SHOULD BE IN THE
VFR RANGE. OTHERWISE...LOOK FOR NORTH WINDS TO PREVAIL THROUGH THE
NEXT 24 HOURS...WITH GUSTS TO 25 KNOTS BY LATE THIS MORNING AND
THROUGH THE AFTERNOON.
CUTTER
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
$$
