FXUS63 KEAX 061742
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1226 PM CDT SAT SEP 6 2008

...UPDATED AVIATION DISCUSSION...

.DISCUSSION...

/411 AM CDT SAT SEP 6 2008/
THE SECOND IN A SERIES OF SHORTWAVES ROTATING THROUGH A PRIMARY
UPPER TROUGH IS FAST APPROACHING THE CWA FROM THE CENTRAL HIGH
PLAINS. AS NOTED YESTERDAY THE ATTENDANT ISENTROPIC LIFT IS STRONGER
AND DEEPER WITH THIS FEATURE. A FAIRLY LARGE AREA OF ELEVATED
SHOWERS AND AND THUNDERSTORMS IS MOVING ALMOST DUE EAST ACROSS SOUTH
CENTRAL AND CENTRAL KS. GFS AND SREF SEEM TO DEPICT THE NEARLY
SATURATED 300-310K ISENTROPIC SURFACES BETTER AND ADVECTS THE WARM
ADVECTION ZONE FASTER TO THE EAST. THE INITIAL AREA OF CONVECTION IS
CURRENTLY MOVING DUE EAST SO HAVE GONE WITH LIKELY POPS OVER THE FAR
SOUTHERN COUNTIES FOR THIS MORNING. MET/MAV MOS POPS PLUS SREF POPS
FAIRLY HIGH AND GIVEN ANTICIPATED STRENGTH AND DEPTH OF ISENTROPIC
LIFT BELIEVE WE WILL SEE QUITE A BIT MORE SHOWER ACTIVITY TODAY VS
FRIDAY. EVEN SO...THE LACK OF LOW LEVEL MOISTURE SUGGESTS QPF
AMOUNTS SHOULD NOT EXCEED A COUPLE TENTHS OF AN INCH. EXPECT TO SEE
CONSIDERABLE CLOUD COVER TODAY AND WITH THE SHOWERS MOVING IN PREFER
COOLER MAV MOS TEMPERATURES.

THE SCATTERED SHOWERS SHOULD LINGER INTO THE EARLY EVENING BEFORE
FALLING APART. MODELS SHOW A BAROCLINIC ZONE WILL SET UP ACROSS
CENTRAL MO TONIGHT/SUNDAY WITH ANOTHER WAVE OF ISENTROPIC LIFT
SWEEPING THROUGH. HOWEVER...LACKING ANY DISCERNIBLE SHORTWAVE THE
RAIN SHOULD BE CONFINED TO A RATHER NARROW CORRIDOR. THE MODELS HAVE
BEEN ADVERTISING THIS FOR SEVERAL RUNS AND POINTING AT THE FAR
SOUTHERN CWA AS HAVING THE BEST CHANCE AT SEEING ANY RAIN ON SUNDAY.
ALSO EXPECT LESS CLOUD COVER TOMORROW SO TEMPERATURES SHOULD REBOUND
BACK INTO THE LOWER/MID 70S...STILL COOLER THAN NORMAL.

A STRONGER SHORTWAVE IS FORECAST TO TRACK SOUTHEAST LATE SUNDAY
NIGHT INTO MONDAY AND PROVIDE A BETTER CHANCE FOR MORE WIDESPREAD
AND HEAVIER POST FRONTAL TYPE RAINS. ONCE AGAIN MODERATELY STRONG
ISENTROPIC LIFT WILL BE THE PRIMARY MECHANISM TO WRING OUT THE
MOISTURE IN THE NEARLY SATURATED MID LEVELS.

MJ

&&

.AVIATION...

FOR THE 18Z TAFS...LIGHT SHRA SHOULD CONTINUE TO LIFT NORTHWARD
THROUGH THE TERMINAL SITES THIS AFTERNOON. THIS PRECIP IS HINGED ON
RATHER STRONG MID-LVL SHORTWAVE IN NORTHERN KANSAS...WITH ASSOCIATED
UPR-LVL JET STREAK OVERHEAD. OVERALL...EXPECTED MVFR CONDITIONS
THROUGH THE AFTERNOON...BEFORE WE ARRIVE ON THE SUBSIDENCE SIDE OF
THE WAVE THIS EVENING.

FOR OVERNIGHT TONIGHT...VERY CONCERNED ABOUT FOG REDEVELOPMENT AT
ALL THREE TAF SITES. SUBSIDENCE BEHIND THE UPR WAVE ALONG WITH VERY
SATURATED GROUNDS AND A LIGHT WIND SHOULD PROMOTE WIDESPREAD FOG
DEVELOPMENT. IN ADDITION...MODEL GUIDANCE IS VERY BULLISH ON THIS
AS WELL...WITH THE CONSERVATIVE SREF ALSO KEYING IN ON FOG
POTENTIAL. MVFR FOG MAY ALREADY DEVELOP BY THE EVENING HOURS...AM
EXPECTING LOCALLY DENSE FOG TO FORM EARLY SUN MORNING.

TWO THINGS CONCERN ME HOWEVER...FIRST BEING AMOUNT OF REMNANT CLOUD
COVER...AND SECONDLY THE POTENTIAL FOR LOW-STRATUS DECK FORMATION
WITH DRIZZLE/HEAVY DEW INSTEAD OF FOG. WILL LIKELY NEED TO WAIT
TILL THE EVENING TO MAKE THE FINAL CALL ON LOWERING VIS FURTHER.


DUX

&&

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

KS...NONE.
$$





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