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000
FXUS63 KTOP 142033
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
333 PM CDT TUE MAY 14 2013

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 331 PM CDT TUE MAY 14 2013

THE CENTRAL PLAINS HAVE QUICKLY TRANSITIONED FROM ABNORMALLY COOL
LESS THAN 48 HOURS AGO...TO ABNORMALLY WARM TODAY WITH TEMPERATURES
WELL INTO THE 90S ACROSS MUCH OF THE FORECAST AREA...AND 100 PLUS
TEMPS IN NEBRASKA. A SURFACE FRONT WAS DRIFTING SOUTH FROM ITS 3 PM
POSITION EXTENDING FROM NORTHWEST KANSAS INTO NORTHEAST NEBRASKA.
THIS FRONT WILL CONTINUE ITS SLOW SOUTHWARD PROGRESSION THROUGH
TOMORROW MORNING. TEMPERATURES IMMEDIATELY IN ADVANCE OF THE
BOUNDARY...AT LEAST THROUGH THE REMAINDER OF TODAY...WARM QUICKLY AS
THE HOTTEST AIRMASS IS WITHIN ABOUT 50 MILES OF THE FRONT ITSELF.
HOWEVER THIS TREND SHOULD DAMPEN DURING THE OVERNIGHT HOURS. DESPITE
MINIMAL MOISTURE CONTENT ALONG THE FRONT...THE HOT TEMPERATURES HAVE
LED TO SPORADIC CONVECTION WHICH HAS INCREASED IN SOUTH CENTRAL
NEBRASKA BETWEEN 2 AND 3 PM. THERE IS SOME POTENTIAL FOR THIS HIGH
BASED AND RATHER WEAK ACTIVITY TO CONTINUE AS THE FRONT APPROACHES
NORTH CENTRAL KANSAS. AT THIS TIME...THE DEEPLY MIXED AND VERY DRY
BOUNDARY LAYER CONDITIONS WOULD SUGGEST CLOUD BASES ABOVE 10000 FEET
WITH VERY LIMITED INSTABILITY AND EVEN A SPRINKLE WOULD SEEM TOO
AGGRESSIVE FOR THE EVENING FORECAST...SO HAVE KEPT IT DRY AT THIS
POINT. IF THE CONVECTIVE ENVIRONMENT ENDS UP MORE ROBUST THAN
PREDICTED THERE COULD BE A FEW THUNDERSHOWERS WITH LIGHT RAIN...
ISOLATED LIGHTNING...AND PERHAPS A WIND GUST LIMITED TO FAR NORTH
CENTRAL KANSAS COUNTIES.

HAVE INCREASED OVERNIGHT LOW TEMPERATURES A BIT WITH EXPECTATION OF
CONTINUED MIXING OVERNIGHT AND WARM TEMPS TO BEGIN WITH. DEWPOINTS
SHOULD ALSO RECOVER A BIT WITH ADVECTION OUT OF TEXAS AND OKLAHOMA.
THE COLD FRONT IS EXPECTED TO STALL OUT NEAR OR JUST NORTH OF I-70
BY WEDNESDAY MORNING. WILL SEE A PERSISTENT LOW LEVEL CONVERGENCE
ZONE SET UP ALONG THIS FRONT FOR WEDNESDAY. MEANWHILE...A WEAK UPPER
LEVEL LOW WILL MOVE INTO EASTERN OKLAHOMA WITH A SLIGHT INFLUX OF
MOISTURE THROUGH THE COLUMN AND A BIT OF MID/UPPER ASCENT. AT THE
SURFACE...IT APPEARS QUITE LIKELY THAT MODEL DEWPOINTS WILL MAINTAIN
THE PERSISTENT HIGH BIAS THROUGH TOMORROW WHILE MODEL TEMPERATURES
WILL MAINTAIN THE COLD BIAS. HAVE THUS GONE A BIT WARMER WITH
FORECAST HIGH TEMPS PARTICULARLY NEAR THE SURFACE BOUNDARY...AND
DRIER WITH DEWPOINTS TOPPING OUT IN THE MIDDLE 60S. IF THESE
CONDITIONS COME TO FRUITION...WOULD EXPECT AN AREA OF 2500+ J/KG OF
MLCAPE COINCIDENT WITH THE LOW LEVEL CONVERGENCE ZONE WITH A RATHER
WEAK CAP BY LATE AFTERNOON. WHILE THERE SHOULD BE PLENTY OF
INSTABILITY...THE DEEP LAYER SHEAR PROFILE IS WEAK AND MESSY WITH
SOUTHERLY LOW LEVEL FLOW AND NORTHEASTERLY UPPER LEVEL FLOW. IF
THUNDERSTORMS ARE ABLE TO DEVELOP...EXPECT AT LEAST A CHANCE OF
ISOLATED STRONG STORMS WITH SOME POTENTIAL FOR MARGINALLY SEVERE
HAIL AND ISOLATED DAMAGING DOWNBURST WINDS DUE TO THE WEAK SHEAR
PROFILE. STORM DEVELOPMENT WILL DEPEND ON BOUNDARY LAYER T/TD
CONDITIONS AND HOW WEAK THE CAP ACTUALLY BECOMES BY AFTERNOON...BUT
CURRENT INDICATIONS SUGGEST ISOLATED TO SCATTERED STORM POTENTIAL.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 331 PM CDT TUE MAY 14 2013

THUNDERSTORM CHANCES MAY INCREASE A BIT WEDNESDAY EVENING AS THE
FRONT PUSHES BACK NORTH AND GIVING RISE TO ELEVATED
CONVECTION...WITH NORTHERN AREAS MORE LIKELY FOR THIS ACTIVITY. ANY
SEVERE THREAT LOWERS WITH INSTABILITY FALLING AND SHEAR STILL
LIMITED. LOW LEVEL MOISTURE OOZES NORTH THROUGH THE NIGHT ON FAIRLY
DEEP SOUTH FLOW. AT THIS POINT THE LOW LEVEL SETUP APPEARS TOO MIXED
AND INVERSION TOO WEAK FOR A MENTION OF DRIZZLE OR FOG THIS FAR
NORTH FOR THE LATE NIGHT AND EARLY THURSDAY HOURS.

WILL KEEP SOME CHANCE FOR THUNDERSTORMS FOR THURSDAY AND THURSDAY
NIGHT AS THE UPPER LOW IN CENTRAL CALIFORNIA TODAY WORKS ITS WAY
EAST ACROSS NORTHERN KANSAS. THIS FEATURE WEAKENS WITH TIME BUT
DEEPENING MOISTURE SHOULD SUPPORT SOME POSSIBILITY OF CONVECTION. AT
THIS POINT FRIDAY APPEARS TO BE THE MOST LIKELY TIME FOR DRY
CONDITIONS AS UPPER HEIGHTS BUILD.

A SLIGHTLY SLOWER TREND CONTINUES TO SHOW ITSELF FOR THE WEEKEND
PERIODS. CYCLOGENESIS TAKES PLACE IN FAR WESTERN KANSAS SATURDAY
WITH THE UPPER FLOW BECOMING SOUTHWEST BUT STILL WEAK BEHIND THE
RIDGE. THERE STILL SHOULD BE SIGNIFICANT CAPPING PLACE...BUT WILL
KEEP SMALL CHANCES GOING...WITH THE SLIGHTLY ENHANCED CHANCES WEST
AND INTO SATURDAY NIGHT WERE CONVECTION COULD PERSIST AS IT MOVES
OFF THE DRYLINE. BETTER CHANCES NOW COME SUNDAY AS THE UPPER TROF
ROTATES INTO THE CENTRAL PLAINS. SURFACE TROF/DRYLINE COMES EAST
WITH COLD FRONT COMING IN BEHIND FOR MORE WIDESPREAD CONCERN. SOME
CIN MAY REMAIN...BUT FORCING SHOULD BE SUFFICIENT FOR AT LEAST
SCATTERED CONVECTION...WITH DEEP LAYER SHEAR INCREASING FOR A SEVERE
WEATHER THREAT. DIVERGENT MODEL SOLUTIONS BECOME APPARENT BY MONDAY
WITH THE 12Z ECMWF NOW ON THE FASTER END WITH THE NORTHERN PLAINS
TROF...PUTTING THE ENTIRE AREA IN THE COLD SECTOR BY MIDDAY
MONDAY...WHILE THE BULK OF OTHER OPERATION RUNS KEEP AT LEAST
SOUTHEASTERN LOCATIONS IN THE WARM SECTOR. AT THIS POINT THE SLOWER
SOLUTIONS SEEM MORE REASONABLE IN THIS SLOW SPRING PATTERN AND SOME
THUNDER CHANCES WILL BE MAINTAINED INTO MONDAY. TEMPERATURES FOR
MUCH OF THE LATE WEEK AND WEEKEND SHOULD BE NEAR TO SLIGHTLY ABOVE
NORMAL...WITH COOLER TEMPS BEHIND THE FRONT BY TUESDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1228 PM CDT TUE MAY 14 2013

VFR CONDITIONS ARE EXPECTED ACROSS THE TAF SITES THROUGH THE
PERIOD. SOUTHWEST WINDS AROUND 20 MPH AND GUSTS UP TO 30 MPH
EXPECTED THIS AFTERNOON ALTHOUGH DECREASING AFTER SUNSET.

SANDERS

&&

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

$$

SHORT TERM...BARJENBRUCH
LONG TERM...65
AVIATION...SANDERS