389
FXUS63 KTOP 041118
AFDTOP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
618 AM CDT SAT JUL 4 2009
UPDATE
UPDATED THE AVIATION DISCUSSION FOR THE 12Z TAFS.
DISCUSSION
SEE PREV DISCUSSION.
AVIATION
MAIN CONCERN IS POTENTIAL FOR LOW CLOUDS TO FILL IN BEHIND THE
FRONT. 11Z OBS SHOW LIFR AND IFR CIGS UPSTREAM INTO SD BEHIND THE
FRONT. ADDITIONALLY MODELS DO NOT ADVECT A LOT OF LOW LEVEL DRY AIR
INTO THE REGION. IN FACT THE NAM IS SUGGESTING SOME INSTABILITY
DEVELOPING THIS AFTERNOON ALONG THE 850 FRONT...WHICH COULD BE IN
THE VICINITY TO TOP AND FOE. NO LARGE SCALE FORCING PROGGED SO THERE
IS LITTLE CONFIDENCE IN LOCATION OF TS DEVELOPMENT THIS AFTERNOON.
HAVE INSERTED MVFR CIGS IN BEHIND THE WIND SHIFT BUT WILL NEED TO
MONITOR TO SEE IF CIGS COME IN LOWER. NORTHEAST FLOW TONIGHT
SUGGESTS LOW LEVEL MOISTURE WILL ADVECT BACK INTO THE TERMINALS SO
AFTER MIXING CIGS ABOVE 3 KFT THIS AFTERNOON...THINK LOW CLOUDS WILL
REDEVELOP. DID NOT HAVE ENOUGH CONFIDENCE TO PUT IFR CIGS IN AS MET
SUGGESTS.
PROBLEM WITH MHK ASOS CAUSING NO OBS...SO AMENDMENTS WILL NOT BE
AVAILABLE UNTIL OBS RETURN.
WOLTERS
PREV DISCUSSION
TODAY/TONIGHT...EARLY THIS MORNING A LARGE SWATH OF SHOWERS AND
EMBEDDED THUNDERSTORMS EXTENDED ALONG AND SOUTH OF THE INTERSTATE 70
CORRIDOR. THIS ACTIVITY CONTINUED TO PUSH OFF TO THE SOUTH AND EAST
AND SHOULD LARGELY EXIT THE CWA BY MID MORNING. WITH THE EXCEPTION
OF A FEW SCATTERED THUNDERSTORMS LINGERING IN EAST CENTRAL
KANSAS...THE MAJORITY OF THE CWA IS EXPECTED TO BE
PRECIPITATION-FREE BY THE AFTERNOON HOURS AND CONTINUING DRY INTO
TONIGHT. THIS SOLUTION IS SUPPORTED BY VIRTUALLY ALL OPERATIONAL
MODEL GUIDANCE AND THE ANTICIPATED DRY AIR ADVECTION WITHIN THE
H7-H3 LAYER COMBINED WITH LARGE SCALE SUBSIDENCE DURING THE LATTER
HALF OF TODAY YIELDS CONFIDENCE TO THIS FORECAST. WHILE THERE MAY BE
NO PRECIPITATION...MOSTLY CLOUDY SKIES LOOK TO PREVAIL AS SEVERAL
MODELS HOLD ON TO HIGH RH WITHIN THE FIRST 5KFT. COLD AIR ADVECTION
COMBINED WITH THE CLOUD COVER WILL HELP KEEP TEMPERATURES BELOW
NORMAL WITH HIGHS RANGING IN THE MIDDLE 70S TO MIDDLE 80S. LOWS
TONIGHT WILL FALL INTO THE LOWER 60S.
SUNDAY/BEYOND...LITTLE IN THE WAY OF ANY SUBSTANTIAL WEATHER SYSTEMS
TO SPEAK OF DURING THE LATTER HALF OF THE WEEKEND INTO EARLY NEXT
WEEK AS A SFC HIGH PRESSURE BUILDS INTO THE REGION. WEAK UPPER
RIDGING BUILDS INTO THE PLAINS STATES AS THE PATTERN BECOMES MORE
AMPLIFIED IN RESPONSE TO A STRONGER SYSTEM MOVING INTO THE PACIFIC
NORTHWEST. MAXIMUM TEMPERATURES WILL RETURN TO AT OR ABOVE NORMAL
LEVELS FOR THE WORK WEEK WITH THE FORECAST LOOKING OVERALL DRY ATTM.
NO SIG CHANGES BEYOND DAY 4 IN THIS PACKAGE.
BLAIR
TOP WATCHES/WARNINGS/ADVISORIES
NONE.
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