567
FXUS63 KEAX 082342
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
642 PM CDT TUE JUL 8 2008
..UPDATED AVIATION DISCUSSION
DISCUSSION
TROPICAL AIRMASS IN PLACE COMPLETE WITH A LARGE PLUME OF SUBTROPICAL
MOISTURE AS SEEN ON WV IMAGERY EXTENDS FROM MEXICO NORTHEASTWARD
THROUGH MO. WEAK NEARLY STATIONARY FRONTAL BOUNDARY EXTENDS FROM
NORTHEAST IA THROUGH NORTHERN KS IS NOT A MAJOR PLAYER FOR
CONVECTION AS BETTER LOW LEVEL SUPPORT IS FOUND ACROSS NORTHERN
OK/SOUTHERN KS INTO CENTRAL MO. CURRENT ACTIVITY IS TIED TO THE
SUBTROPICAL PLUME AND ITS INTERACTION WITH A STRUNG OUT MID LEVEL
VORTICITY LOBE WHICH LIES NEARLY WEST-EAST ACROSS THE SOUTHERN HALF
OF THE CWA. DIFFERENTIAL SURFACE HEATING HELPED IGNITE MULTICELL
CLUSTERS WITHIN A NON-CAPPED ENVIRONMENT AND THEY HAVE BECOME VERY
EFFICIENT HEAVY RAIN PRODUCERS. INITIALLY...THE BEST BET FOR FLASH
FLOODING APPEARS TO BE OVER THE SOUTHERN THIRD OF THE CWA AS SEVERAL
ROUNDS OF REPEAT CONVECTION ARE POSSIBLE. SEVERE THREAT IS JUST
ABOUT OVER AND WILL LIKELY CANCEL THE ENTIRE SEVERE THUNDERSTORM
WATCH BY 22Z.
OTHERWISE...THE NORTHERN EDGE OF THE RAIN WILL GRADUALLY SHIFT SOUTH
WITH LITTLE IF ANY RAIN EXPECTED NORTH OF THE MO RIVER AFTER
MIDNIGHT...AND COMPLETELY OUT OF THE FAR SOUTHERN CWA BY MID
WEDNESDAY MORNING. SKIES SHOULD CLEAR OUT OVER MOST OF THE REGION
WITH A SLIGHTLY DRIER/COOLER NORTHEAST BOUNDARY LAYER WIND PUSHING
IN FROM IOWA/WESTERN IL. FROM WEDNESDAY AFTERNOON THROUGH THE NIGHT
WILL NEED TO WATCH FOR ANY IMPULSE EMBEDDED WITHIN THE NORTHWEST
FLOW AS MODELS HAVE SHOWN SOME RUN-TO-RUN CONSISTENCY IN TRACKING A
FEATURE THROUGH NORTHERN MO AND GENERATING WIDELY SCATTERED
CONVECTION. LATER SHIFTS MAY NEED TO UP POPS INTO THE CHANCE
CATEGORY.
THURSDAY SHOULD BE DRY WITH BUT WITH THE RETURN OF A MUGGY AIRMASS
AS THE SURFACE HIGH RETREATS THROUGH THE OH VALLEY. NEAR SEASONAL
AVERAGES FOR MAX/MIN TEMPERATURES.
MJ
MEDIUM RANGE (FRIDAY THROUGH TUESDAY)...
DIRTY FLOW CONTINUES TO BE PROGGED THROUGH THE EXTENDED FORECAST.
MODELS GENERALLY AGREE ON LARGE SCALE FEATURES WITH EXPECTED TIMING
AND POSITION DIFFERENCES IN THE SMALLER SCALE. LARGE UPPER LOW WILL
MOVE ACROSS SOUTHWEST CANADA DURING THE EXTENDED ALLOWING FOR SHORT
WAVE RIDGING AND RETURN TO INCREASED LOW LEVEL MOISTURE OVER THE
AREA. GIVEN THE MYRIAD OF RIPPLES IN THE FLOW PINNING DOWN ANY GIVE
TIME FOR RAINFALL IN THE EXTENDED WILL BE DIFFICULT. MODELS SHOW
SOMETHING FRIDAY OR FRIDAY NIGHT...POSSIBLY SATURDAY AND THEN MONDAY
INTO MONDAY NIGHT WITH A STRONGER WAVE. GENERAL BROAD BRUSHED LOW
POPS IS APPROPRIATE IN THIS SITUATION. FORECAST DIDNT CHANGE A WHOLE
LOT FROM PREVIOUS VERSIONS.
AB
AVIATION
FOR THE 00Z TAFS...PRIMARY CONVECTION HAS MOVED SOUTH OF THE
TERMINALS. EXCEPT FOR A FEW SPRINKLES AT MCI/MKC THE RAIN HAS ENDED.
SOME BRIEF MVFR CEILINGS AT THE KC SITES FOR THE FIRST HOUR OF THE
FORECAST...OTHERWISE VFR CONDITIONS WILL PREVAIL FOR THE FORECAST
PERIOD. SOME CONCERN THAT ISOLATED CONVECTION COULD FORM WEDNESDAY
AFTERNOON AS THE FRONTAL BOUNDARY JUST ENTERING THE NORTHWEST TIP OF
MO MAY STALL NEAR ALL 3 TERMINALS. SO WILL INTRODUCE CB IN THE
FORECAST WITH THE IDEA THAT LATER UPDATES MAY INCLUDE A PROB30 FOR
THE AFTERNOON AND EARLY EVENING HOURS.
MJ
EAX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
KS...NONE.
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