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000
FXUS63 KTOP 170513
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1213 AM CDT FRI MAY 17 2013

...UPDATE TO AVIATION...

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 343 PM CDT THU MAY 16 2013

LOW LEVEL MOISTURE BECOMING MORE PREVALENT WITH MODERATE
SOUTH-SOUTHEAST WINDS OUT OF THE SOUTHERN PLAINS UPPER LOW. LARGE
SCALE SUBSIDENCE WAS OCCURRING IN MUCH OF EASTERN KANSAS BEHIND THIS
SYSTEM...WITH A FEW ROUNDS OF CONVECTION TO THE NORTH AND
NORTHWEST AHEAD OF AND WITH AN UPPER LEVEL WAVE OVER NORTHEAST
COLORADO. VISIBLE SATELLITE SHOWS CUMULUS FIELD BECOMING MORE ROBUST
IN CENTRAL PORTIONS OF THE COUNTY WARNING AREA AND LOCAL RADARS
INDICATING VERY ISOLATED AND WEAK RETURNS.

PRECIPITATION CHANCES STILL LOOK RATHER MEAGER THROUGH FRIDAY
AFTERNOON. ALTHOUGH LOW LEVELS CONTINUE TO REMAIN MOIST...THERE IS
LITTLE FORCING FOR LIFT OR A MEANS TO MAINTAIN LIFT. THE LOCAL
RETURNS MAY CONTINUE THROUGH LATE AFTERNOON AND THERE IS INSTABILITY
FOR ANY DEEPER CUMULUS TO TAP INTO...BUT ANYTHING MORE THAN ISOLATED
AND VERY LIGHT AMOUNTS SEEMS TO BE UNLIKELY. WILL WATCH LATEST
TRENDS BUT WILL LIKELY GO WITHOUT A MENTION. SHORT-RANGE MODELS ARE
VERY SIMILAR WITH THE NORTHWEST KANSAS STORMS WEAKENING AS IT MOVES
INTO CENTRAL KANSAS...AND VERY LIMITED INFLOW AND THETA-E ADVECTION
WOULD SUPPORT THIS IDEA. THE BIGGER IMPACTS TONIGHT INTO FRIDAY
COULD BE FROM ANOTHER ROUND OF FOG DEVELOPING AFTER 06Z. LOW LEVEL
CONDITIONS APPEAR RATHER SIMILAR TO THOSE OF THIS MORNING...THOUGH
THE DIFFICULTY IS IF STRATUS WILL FORM FIRST AND LIMIT FOG
FORMATION. WILL INCLUDE PATCHY WORDING FOR NOW AND SEE HOW
CONDITIONS PLAY OUT OVER THE NEXT SEVERAL HOURS. SHOULD SEE A BIT
MORE SUN FOR FRIDAY WITH RISING HEIGHTS AND SLIGHTLY WARMER TEMPS.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 343 PM CDT THU MAY 16 2013

A MID LEVEL TROUGH WILL MOVE INTO THE ROCKIES FRIDAY NIGHT AND
SATURDAY. AHEAD OF THE TROUGH A RIDGE WILL BUILD OVER THE CENTRAL
PLAINS WHILE A SURFACE LOW DEVELOPS OVER EASTERN COLORADO THEN
DEVELOPS OVER SOUTHWEST KANSAS. ATMOSPHERE BECOMES INCREASINGLY
CAPPED OFF SATURDAY AND CONTINUES SATURDAY NIGHT OVER THE EASTERN
SECTIONS OF THE CWA. MID LEVELS FAIRLY DRY AND MID LEVEL LAPSE RATES
STEEPEN BY SUNDAY MORNING. AN INITIAL WAVE WILL EJECT OUT OF THE
UPPER TROUGH AND MOVE NORTHEAST INTO CENTRAL KANSAS BY SUNDAY
MORNING. WITH THE DRY LINE REMAINING WEST OF THE CWA IN WESTERN
KANSAS SATURDAY NIGHT MAY SEE SOME STORMS IN NORTH CENTRAL KANSAS
SATURDAY NIGHT AS THEY DEVELOP ALONG THE DRYLINE. TEMPERATURES WILL
CONTINUE TO BE MILD WITH MID 60S FRIDAY NIGHT...HIGHS IN THE MID 80S
SATURDAY AND LOWS IN THE UPPER 60S SATURDAY NIGHT.

A COUPLE OF WAVES WILL MOVE NORTHEAST INTO NORTHEAST KANSAS SUNDAY
AS THE UPPER TROUGH MOVES INTO THE HIGH PLAINS. ASCENT WILL INCREASE
THROUGH THE AFTERNOON AND CONTINUE INTO THE NIGHT SUNDAY NIGHT. THE
DRYLINE WILL BE IN CENTRAL KANSAS AND IS FORECAST TO MOVE INTO THE
WESTERN CWA SUNDAY AFTERNOON. UPPER FORCING IS EXPECTED OVERCOME
CONVECTIVE INHIBITION FOR STORMS TO DEVELOP AND MOVE INTO NORTHEAST
KANSAS. AHEAD OF THE DRYLINE FRONT MOISTURE WILL POOL ACROSS EAST
CENTRAL KANSAS SUNDAY EVENING. SHEAR IS CONDUCIVE FOR SUPERCELL
DEVELOPMENT. ML CAPE RANGES FROM 2500 J/KG TO 3500 J/KG IN THE
AFTERNOON AND EVENING. ANY SUPERCELL THUNDERSTORM WILL BE CAPABLE OF
PRODUCING LARGE HAIL AND DAMAGING OUTFLOW WINDS...ALONG WITH
ISOLATED TORNADOES SUNDAY AND SUNDAY NIGHT. THROUGH THE LATE EVENING
HOURS INTO LATE SUNDAY NIGHT THE FOCUS FOR STORMS WILL MOVE OFF TO
THE SOUTHEAST. 53

WITH THE MAIN UPPER TROUGH CONTINUING TO REMAIN NEARLY STATIONARY
ACROSS THE NORTHERN PLAINS...LATEST RUNS OF THE GFS AND ECMWF STILL
INDICATE ANOTHER EMBEDDED SHORTWAVE TROUGH TO ROTATE INTO THE
NORTHEAST KANSAS AREA MONDAY AFTERNOON. MID LEVEL VORT MAX IS
PROGGED TO ARRIVE SOMETIME DURING THE LATE MORNING TO AFTERNOON
HOURS PROVIDING AMPLE LIFT FOR ANY DEVELOPING UPDRAFTS. AT THE
SURFACE THE COLD FRONT APPEARS TO REMAIN JUST TO OUR WEST MONDAY
MORNING AS WARM AIR AND DEWPOINT READINGS NEAR 60 DEGREES STREAM
NORTHEASTWARD. STILL SOME QUESTION AS TO HOW PREVIOUS OVERNIGHT
CONVECTION WILL GIVE ENOUGH TIME FOR THE ATMOSPHERE TO
RECOVER...HOWEVER AS THE COLD FRONT GRADUALLY TRACKS EASTWARD EXPECT
TO SEE STRONG TO SEVERE STORMS DEVELOPING ALONG AND AHEAD OF IT.
SURFACE BASED CAPE VALUES OVER 3000 J/KG WITH 0-6 KM BULK SHEAR OVER
60 KTS WILL SUPPORT SUPER CELL STORMS DEVELOPING PRIMARILY ALONG AND
SOUTH OF INTERSTATE 70 WHERE AMPLE SHEAR AND INSTABILITY IS
STRONGEST. EXPECT THE CELLS TO EVOLVE INTO A SQUALL LINE WHERE LARGE
HAIL...DAMAGING WINDS AND HEAVY RAINFALL ARE POSSIBLE. FORECAST
SOUNDINGS PWAT VALUES OVER AN INCH AND POSSIBILITY OF HEAVY RAINFALL
MONDAY WITH PREVIOUS RAINFALL SUNDAY COULD ENHANCE A LOCALIZED FLOOD
RISK FOR THE CWA WHERE SOIL MOISTURE MAY BE AT OR NEAR SATURATED.
STILL UNCERTAINTY IN MODEL SOLUTIONS ON THE TIMING BETWEEN UPPER
SUPPORT AND POSITION OF BOUNDARY...WITH THE ECMWF BEING CONSISTENTLY
SLOWER AND THE GFS BRINGING THE FRONT THROUGH THE CWA BY MONDAY
EVENING. IN BOTH INSTANCES CONVECTION DEVELOPS AND SO CONTINUED WITH
LIKELY POPS ALONG AND SOUTH OF THE KANSAS TURNPIKE WITH CHANCES
INSERTED ELSEWHERE. RAIN CHANCES COME TO AN END TUESDAY AFTERNOON AS
THE SYSTEM CLEARS OUT AND HIGH PRESSURE RETURNS THROUGH WEDNESDAY
AFTERNOON. AS ZONAL FLOW ALOFT REIGNS GUIDANCE SUGGESTS A SLIGHT
CHANCE FOR THUNDERSTORMS OVER NORTH CENTRAL KANSAS WEDNESDAY EVENING
AS AN UPPER TROUGH SHIFTS EASTWARD OVER THE CENTRAL PLAINS. 12Z
ECMWF DEPICTS A SIMILAR RESULT WITH A SLOWER ONSET ON TIMING SO WILL
KEEP A SLIGHT CHANCE MENTION.

WITH NO STRONG INDICATION OF COOLER AIR MASSES OR STRONG FRONTAL
BOUNDARIES...TEMPERATURES ARE ON PAR TO REMAIN IN THE UPPER 70S FOR
HIGHS AND LOWS IN THE 50S FROM MONDAY THROUGH THURSDAY. BOWEN

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1156 PM CDT THU MAY 16 2013

AN AREA OF STRATUS HAS DEVELOPED JUST EAST OF TOP/FOE AT 05Z AND
SHOULD INCREASE IN SIZE...AND EVENTUALLY BUILD DOWN TO MVFR THROUGH
THE EARLY MORNING HOURS. EXPECT INITIAL MVFR CONDITIONS TO
GRADUALLY BUILD DOWN TO IFR AT TOP/FOE WHILE MHK WILL REMAIN VFR
LONGER ON THE WESTERN FRINGE OF CLOUDS. QUITE A BIT OF UNCERTAINTY
IN THIS TAF REGARDING EVENTUAL CIG HEIGHTS AND VIS
RESTRICTIONS...AS WELL AS OVERALL COVERAGE AND PREVALENCE OF THE
FEATURES. HAVE TRIED TO HIGHLIGHT THE MOST LIKELY TIMES FOR
REDUCED CONDITIONS WITHIN THE TAF.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...65
LONG TERM...53/BOWEN
AVIATION...BARJENBRUCH