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000
FXUS63 KTOP 160511
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1211 AM CDT THU MAY 16 2013

...UPDATED TO AVIATION...

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 310 PM CDT WED MAY 15 2013

LOCAL AREA IS FLANKED BY TWO SYNOPTIC FEATURES...A STALLING FRONT
DRAPED OVER NORTHERN KANSAS AND AN UPPER LEVEL LOW OVER CENTRAL
OKLAHOMA. ENOUGH CLEARING AND GENERALLY SOUTH WIND BETWEEN THESE
FEATURES HAS ALLOWED TEMPS TO AGAIN RISE WELL INTO THE 80S.

SURFACE WINDS IN SOUTHERN AND WESTERN NEBRASKA HAVE VEERED TO A
MORE SOUTHEASTWARD DIRECTION AS SURFACE HIGH PRESSURE PUSHES EAST.
IN COMBINATION WITH MODELS...THE FRONT SHOULD SLOWLY LOSE CONTINUITY
AND MIX NORTH INTO NEBRASKA OVER THE NEXT 9-15 HOURS. UNTIL
THEN...CONVERGENCE MAY BE ENOUGH TO OVERCOME SOME REMNANT CAPPING
FOR ISOLATED TO SCATTERED STORMS NEAR THE BOUNDARY. MODELS CONTINUE
TO BE SLIGHTLY HIGH ON DEWPOINTS...AND INSTABILITY MAY NOT BE QUITE
WHAT WAS EARLIER SUGGESTED. ALONG WITH WEAK WIND FIELDS...SEVERE
WEATHER WOULD BE QUITE UNLIKELY IN ANY STORM THAT COULD FIRE...WITH
PERHAPS DOWNBURST WINDS IN COLLAPSING UPDRAFTS BEING THE MAIN
CONCERN. ANY ACTIVITY SHOULD SLOWLY DECREASE BY LATE EVENING WITH A
LOSS OF HEATING AND THE BOUNDARY RETREATING...WITH ANY ISENTROPIC
LIFT OVER IT ALSO RETREATING. WILL KEEP SMALL PRECIP CHANCES FOR THE
SOUTHEAST INTO MIDDAY THURSDAY AS THE LOW TRACKS NORTHEAST INTO
SOUTHERN MISSOURI...BUT THURSDAY SHOULD BRING DRY CONDITIONS FOR
MOST LOCATIONS. LOW CLOUD LOOKS TO FORM LATE TONIGHT AND WITH
LIMITED WINDS MAY STICK AROUND INTO THE LATE MORNING. LOW LEVEL
TRAJECTORIES OFF THE UPPER LOW SHOULD KEEP HIGHS FROM BREACHING THE
LOWER 80S.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 PM CDT WED MAY 15 2013

FORECAST FOCUS REMAINS ON THE EVOLUTION OF THE APPROACHING LONGWAVE
TROUGH AND IMPACTS ON WEATHER THROUGH THE WEEKEND INTO NEXT WEEK.

A WEAK UPPER WAVE WILL DRIFT ACROSS NEBRASKA THU NIGHT AND THERE
HAVE BEEN CONSISTENT SIGNALS FOR CONVECTION ACROSS THE HIGH PLAINS
INTO WESTERN KS/NE. HOWEVER...LLJ AND 850MB THETAE RIDGE AND
ADVECTION REMAINS WELL WEST OF THE CWA SO WOULD EXPECT THE CWA TO
REMAIN DRY WITH ONLY SMALL CHCS FOR STORMS ACROSS THE FAR NW
COUNTIES.

FRIDAY SHOULD BE A DRY AND WARM DAY AS THE UPPER RIDGE BUILDS OVER
THE PLAINS IN RESPONSE TO THE DEEPENING TROUGH ACROSS THE WEST.
HIGHS SHOULD REACH INTO THE LOW AND MID 80S WITH DEWPOINTS GRADUALLY
INCREASING INTO THE 60S AS THE PERSISTENT SOUTH WINDS FINALLY TAP
INTO THE GULF MOISTURE.

CONDS WILL REMAIN DRY AND MILD FRI NIGHT WITH LOWS IN THE 60S. BY
SAT...THE FIRST SHORTWAVE WITHIN THE DEEPENING LONGWAVE TROUGH WILL
EMERGE INTO THE HIGH PLAINS BY EVENING. LEE TROUGH/LOW PRESSURE WILL
DEEPEN AND REMAIN NEARLY STATIONARY ACROSS WESTERN KS. ANY DRYLINE
PUSH SHOULD OCCUR ACROSS FAR WESTERN KS KEEPING ANY STORM INITIATION
WELL WEST OF THE CWA. WILL LEAVE SMALL POPS IN FAR NW COUNTIES FOR
NOW BUT CHCS APPEAR TO BE DECREASING FOR SAT AFTERNOON STORMS IN
CENTRAL KS.

SAT NIGHT...FIRST SHORTWAVE WILL MOVE INTO KS AND THIS SHOULD ACT TO
PUSH THE SFC LOW EAST NORTHEAST WITH TIME. EML/CAP MAY ACT TO KEEP
BETTER STORM CHCS NORTHWEST OF THE CWA SAT NIGHT BUT WILL LEAVE
SMALL CHCS IN THE NW HALF FOR THE TIME BEING.

SUN...UPPER TROUGH AND SFC LOW WILL COMBINE TO PRODUCE STORMS BY
MIDDAY OR EARLY AFTERNOON GIVEN POSITION OF THE UPPER TROUGH WHICH
WILL BE MOVING ACROSS THE AREA BEFORE PEAK HEATING. CAPE/SHEAR
VALUES WILL SUPPORT SEVERE STORMS SO THE PREVIOUS THINKING REMAINS
ON TRACK FOR POTENTIAL SEVERE AREA WIDE SUNDAY.

SUNDAY NIGHT-MON...FIRST UPPER WAVE WILL DEPART WITH ADDITIONAL
UPPER ENERGY FORECAST TO MOVE INTO COLORADO. THIS WILL CAUSE THE
FRONT TO SLOW/STALL SOMEWHERE ACROSS THE CWA AND COULD PRODUCE
ANOTHER CHC FOR SEVERE STORMS MAINLY ACROSS THE SOUTHEAST HALF OF
THE CWA MONDAY. CONFIDENCE IS LOWER FOR THE MONDAY SCENARIO GIVEN
UNCERTAINTY IN THE LOCATION OF THE FRONT. SHEAR PARAMETERS APPEAR
STRONGER ON MON SO WILL HAVE TO WATCH THIS EVOLVE.

RISK FOR SEVERE STORMS SHOULD END BY MON NIGHT WITH COOLER AND LESS
HUMID CONDS FORECAST INTO MID WEEK AS THE UPPER TROUGH MOVES ACROSS
THE REGION.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1152 PM CDT WED MAY 15 2013

VFR FORECAST FOR THE FIRST FEW HOURS OF THE TAF BUT STRATUS
DEVELOPING UPSTREAM LENDS MORE CONFIDENCE TO A PERIOD OF MVFR
CIG/VIS WITH A FEW HOURS OF IFR CIGS AS WELL. MOST LIKELY TIME
FRAME FOR REDUCED CIGS/VIS WILL FALL BETWEEN 09Z AND 15Z...WITH
POTENTIAL TO LAST BEYOND 15Z...PARTICULARLY AT TOP/FOE. MAIN
UNCERTAINTY LIES IN IF/HOW FAST CIGS WILL DECREASE INTO IFR AND
HOW LONG CIGS WILL HANG AROUND BEFORE BREAKING UP.

BARJENBRUCH

&&

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

$$

SHORT TERM...65
LONG TERM...OMITT
AVIATION...BARJENBRUCH