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000
FXUS63 KTOP 252350 AAA
AFDTOP

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TOPEKA KS
650 PM CDT SAT MAY 25 2013

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 349 PM CDT SAT MAY 25 2013

AT THE SURFACE A FAIRLY DEEP SURFACE TROUGH HAS SET UP ON THE LEE
SIDE OF THE ROCKIES ACROSS WYOMING AND EASTERN COLORADO. THE FAR
EASTERN EDGE OF THE TROUGH CURRENTLY RESIDES OVER THE FORECAST AREA
BRINGING GOOD SOUTHERLY WARM/MOIST AIR FROM THE SOUTHERN PLAINS/GULF
OF MEXICO. VISIBLE IMAGERY SHOWS THIS STREAM OF MOISTURE INTO THE
AREA IN THE FORM OF A CUMULUS FIELD DEEP IN THE SOUTHERLY FLOW. IN
THE MID LEVELS H5 RIDGING IS HELPING TO KEEP TEMPS WARM TODAY WITH
LARGE SCALE SUBSIDENCE. EXPECT THE REMAINDER OF THE DAY TO BE
DRY...ESPECIALLY SOUTH OF INTERSTATE 70. THE NEXT CHANCE FOR SHOWERS
AND THUNDERSTORMS WILL LIKELY COME LATER TONIGHT ALONG HWY 36 TOWARD
THE NEBRASKA BORDER IN FAR NORTHERN AND NORTHEAST KANSAS. A
STRENGTHENING LOW LEVEL JET OF 30-40 KTS WILL NOSE INTO FAR SOUTHERN
NEBRASKA KICKING OFF A ROUND OF ELEVATED STORMS. THE SOUTHERN EXTENT
OF THESE SHOWERS IS A LITTLE UNCERTAIN AS A FEW STORMS MAY SPILL
INTO THE FAR NORTHERN ZONES...BUT SHOWERS ARE PRETTY UNLIKELY TO
REACH AS FAR SOUTH AT I-70. SOME SHORT RANGE CONVECTIVE ALLOWING
MODELS DO HINT AT A LINE OF WARM AIR ADVECTION SHOWERS FORMING ALONG
THE KS/MO BORDER IN THE FAR EASTERN CWA. STRONG ISENTROPIC ASCENT
ALONG THE 310 AND 315 K THETA E SURFACES WILL GIVE ASCENT TO
POSSIBLE ELEVATED THUNDERSTORMS ON SUNDAY. FORECAST SOUNDINGS SHOW
OFF A PRETTY STOUT LOW LEVEL INVERSION INDICATING STRONG CAPPING
OVER THE AREA. THIS WOULD CERTAINLY MITIGATE THUNDERSTORM
DEVELOPMENT...AND SHOULD STORMS FORM THEY WOULD LIKELY BE ELEVATED
IN NATURE. BUT WITH 2000 TO 3000 J/KG OF MU CAPE THEY WOULD
CERTAINLY BE CONVECTIVE WITH HEAVY RAIN POSSIBLE. GIVEN THE STRONG
CAP IN PLACE AM NOT OVERLY EXCITED ABOUT RAIN CHANCES ON
SUNDAY...BUT TO ALLOW FOR THE STRONG ISENTROPIC ASCENT WILL GO WITH
SCHC POPS FOR THE AREA ON SUNDAY AFTERNOON/EVENING.

JL

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 349 PM CDT SAT MAY 25 2013

ON SUNDAY A SHORTWAVE WILL PROGRESS EASTWARD THROUGH THE CENTRAL
AND NORTHERN PLAINS. LOW LEVEL MOISTURE ADVECTION ALONG WITH SURFACE
HEATING WILL INCREASE THE INSTABILITY ACROSS THE AREA. DEEP LAYER
SHEAR WILL ALSO INCREASE IN ASSOCIATION WITH THE PROGRESSING WAVE.
THEREFOR...THERE IS THE POSSIBILITY OF STRONG TO SEVERE STORMS
SUNDAY EVENING AND OVERNIGHT ESPECIALLY NORTH CENTRAL KANSAS.
ANOTHER WAVE WILL EJECT INTO THE CENTRAL PLAINS ON MONDAY WHILE AT
THE SURFACE A DRY PUNCH WORKS INTO WESTERN AND CENTRAL KANSAS. THE
INSTABILITY AND DEEP LAYER SHEAR LOOK TO SUPPORT ANOTHER ROUND OF
STRONG TO SEVERE STORMS ACROSS NORTH CENTRAL KANSAS. AS THE MID
LEVEL SHORTWAVE APPROACHES...HEIGHT FALLS WILL HELP WEAKEN THE CAP
ASSOCIATED WITH AN EML ACROSS THE REGION. SURFACE CONVERGENCE NEAR
THE DRY PUNCH WILL ALSO HELP INITIATE AND FOCUS THE CONVECTION.
MONDAY NIGHT THE THREAT FOR STRONG TO SEVERE STORMS WILL SLIDE INTO
NORTHEAST KANSAS. WITH NOT MUCH CHANGE IN THE OVERALL PATTERN A
SIMILAR SITUATION WILL OCCUR TUESDAY AFTERNOON AND EVENING ALTHOUGH
THE SHORTWAVE IS PLACED FURTHER WEST ATTM. WITH A STRONG CAP IN
PLACE AND THE FOCUS FOR CONVECTION FURTHER WEST DID NOT INCREASE
POPS FOR THAT PERIOD.

SANDERS

THE LONG TERM FORECAST TUESDAY NIGHT THROUGH SATURDAY REVOLVES
AROUND THE EVOLUTION OF A COMPLEX WESTERN CONUS TROUGH AND A SERIES
OF SHORT WAVE TROUGHS ROTATING OUT OF THE MAIN SYSTEM. CURRENT
INDICATIONS SUGGEST AT LEAST ONE...IF NOT MORE...ROUNDS OF SEVERE
WEATHER ACROSS CENTRAL AND EASTERN KANSAS AS THIS SYSTEM IMPACTS THE
LOCAL FORECAST AREA.

AT THE BEGINNING OF THE PERIOD...MUCH OF EASTERN KANSAS SHOULD BE
WELL CAPPED...BUT THE LATEST MODEL GUIDANCE SUGGESTS THAT THE WEAK
ENERGY EJECTING FROM THE LONG WAVE TROUGH MAY BE SUFFICIENT TO
INITIATE THUNDERSTORMS IN CENTRAL KANSAS AND NEBRASKA DURING THE
LATE AFTERNOON/EVENING HOURS OF TUES/WED WHERE THE CAP WILL BE A BIT
WEAKER. THESE THUNDERSTORMS WOULD THEN AT LEAST PRESENT THE
POTENTIAL FOR OVERNIGHT CONVECTION TO PUSH EAST WELL INTO THE CAPPED
AIRMASS BEFORE WEAKENING. THIS POTENTIAL ALSO SEEMS TO INCREASE FROM
DAY TO DAY WITH THE GRADUAL EASTWARD PROGRESSION OF THE LONG WAVE
TROUGH AXIS. ONE OF THE STRONGEST SHORT WAVES IS FORECAST TO ENHANCE
LIFT OVER WESTERN AND CENTRAL KANSAS BY LATE WEDNESDAY...BUT IS
ORIENTED SUCH THAT THE UPPER FLOW MAY BE MORE SOUTHERLY THAN
WESTERLY...AND WOULD EXPECT STORM MOTION TO GENERALLY KEEP ACTIVITY
OVER CENTRAL KANSAS INITIALLY...BEFORE POSSIBLY PROPAGATING EAST
AFTER MIDNIGHT. SEVERE WEATHER SEEMS TO BE A DECENT POSSIBILITY IN
CENTRAL KANSAS LATE WEDNESDAY GIVEN THE STRONG DEEP LAYER SHEAR AND
INSTABILITY COINCIDING WITH THE WAVE. THIS IS A PERIOD WORTH
WATCHING IN CASE ISOLATED STORMS ARE ABLE TO MAKE IT AS FAR EAST AS
NORTH CENTRAL KANSAS.

THE UPPER LEVEL FLOW PATTERN SEEMS TO BECOME MORE FAVORABLE FOR
SEVERE WEATHER POTENTIAL BY THURSDAY AND FRIDAY AS THE MID AND UPPER
FLOW BECOMES MORE WESTERLY WHILE THE DRY LINE SETS UP OVER CENTRAL
KANSAS EACH AFTERNOON. DEEP LAYER SHEAR OF 50 KNOTS OR GREATER...
MODERATE INSTABILITY...STORM MOTION PERPENDICULAR TO THE DRY LINE...
AND POTENTIAL FOR QUITE A BIT OF LOW LEVEL SHEAR SHOULD ALL BE
PRESENT BASED ON MOST MODEL GUIDANCE FOR THURSDAY. AT THE SAME
TIME...MUCH UNCERTAINTY LIES IN DETAILS BEYOND WHAT THE MID/LONG
RANGE MODELS CAN PROVIDE. PRIMARY QUESTION MARKS INCLUDE THE
SPECIFIC TIMING OF THE SHORT WAVE TROUGHS AND ASSOCIATED
ASCENT/DESCENT...AND INTERACTION WITH OUTFLOW BOUNDARIES AND REMNANT
NOCTURNAL CONVECTION. REGARDLESS...THURSDAY HOLDS GOOD POTENTIAL FOR
SEVERE WEATHER.

FRIDAY STANDS TO HOLD SIMILAR CONDITIONS IN MANY REGARDS...INCLUDING
BOTH THE FAVORABLE PARAMETERS AS WELL AS THE POTENTIAL
UNCERTAINTIES. A DRY LINE/PACIFIC FRONT SHOULD BE DRAPED ACROSS THE
FORECAST AREA BY FRIDAY AFTERNOON AS THE TROUGH DEEPENS TO THE
NORTH. THE STRONG DEEP LAYER SHEAR...LOW LEVEL SHEAR...AND
INSTABILITY WILL BE IN PLACE ALTHOUGH STORM MOTIONS MAY NOT BE SO
PERPENDICULAR TO THE FRONTAL BOUNDARY. WITH ALL OF THAT IN MIND...
FRIDAY ALSO SEEMS TO HOLD THE POTENTIAL FOR SEVERE WEATHER. BY
SATURDAY MOST INDICATIONS SUGGEST THAT THE FRONT PUSHES SOUTH OF THE
FORECAST AREA. IF THIS IS THE CASE...WE MAY SEE A PERIOD OF SOME
DRYING WITH A BIT OF NORTHWEST FLOW AND SOME UPPER RIDGING. ONE
OTHER THING TO KEEP IN MIND IS THAT WITH NUMEROUS ROUNDS OF
THUNDERSTORMS POSSIBLE IN THE COMING WEEK...FLOODING POTENTIAL WILL
BE ON THE INCREASE AND COULD BECOME AN ISSUE.

BARJENBRUCH

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 646 PM CDT SAT MAY 25 2013

SOUTHERLY WIND GUSTS WILL SUBSIDE THROUGH 01Z...THEN INCREASE
AGAIN AFT 15Z...OTHERWISE SUSTAINED 7-14 KTS WILL BE THE RULE
THROUGH THE PERIOD WITH VFR CONDITIONS. CHANCES FOR CONVECTION
AFFECTING THE TERMINALS REMAINS TOO LOW TO INCLUDE IN FCST AT THIS
TIME.

&&

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

$$

SHORT TERM...LEIGHTON
LONG TERM...BARJENBRUCH/SANDERS
AVIATION...63