National Weather Service Raw Text Product

868 
FXUS63 KTOP 212037
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
337 PM CDT SUN JUL 21 2013

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 334 PM CDT SUN JUL 21 2013

CONSIDERABLY LESS ACTIVE TODAY AS SUBSIDENCE BEHIND A SMALL SCALE 
SHORTWAVE HAS KEPT A LID ON CONVECTION ACROSS MUCH OF THE NORTHERN 
COUNTIES. STILL A FEW CELLS POPPING UP SOUTH OF INTERSTATE 70 BUT AT 
THIS TIME EXPECT THIS ACTIVITY TO REMAIN ISOLATED INTO THE EVENING 
HOURS THEN CLEAR. SHORTWAVE IN NEBRASKA MOVING TO THE SOUTHEAST HAS 
PRODUCED LITTLE IN THE WAY OF STORMS TODAY...AND EXPECT THIS TREND 
TO CONTINUE AS LOCAL ATMOSPHERE STARTS TO STABILIZE IN THE LOW 
LEVELS. MAY SEE SOME FOG POTENTIAL IF SKIES CAN CLEAR AND WINDS 
LIGHTEN FOR SEVERAL HOURS OVERNIGHT.  WILL PASS ON TO EVENING SHIFT 
TO BE MINDFUL OF DEVELOPMENT POTENTIAL.  

THE RISK FOR SEVERE STORMS IS ON THE INCREASE INTO TOMORROW...AS A 
COLD FRONT PUSHES SOUTHWARD TOWARD OUR AREA IN THE LATE AFTERNOON AND 
EVENING HOURS.  AS THE FRONT APPROACHES...MID LEVEL THERMAL RIDGE 
AND CAP BOTH PUSH NORTHEASTWARD...LEAVING THE GRADIENT ACROSS THE 
FAR NORTHEASTERN COUNTIES BY LATE AFTERNOON AND LIKELY CAPPING OFF 
CONVECTIVE POTENTIAL IN ABSENCE OF STRONGER FORCING.  AS 
THUNDERSTORMS DEVELOP ALONG THE FRONT AND MOVE SOUTHEASTWARD...ALSO 
EXPECT A ROUND OF STORMS TO DEVELOP ALONG THE EDGE OF THE CAP ACROSS 
THE NORTHEAST. NAM PROGS CONVECTION ACROSS THE FAR NW COUNTIES BY 
EARLY AFTERNOON...BUT THINK THIS IS IN RESPONSE TO A SMALL SCALE 
FEATURE THAT MOVES OUT AHEAD OF THE FRONT INTO THE WARM AIR AND 
GENERATES CONVECTION TOO EARLY IN THE MODEL.  FOR NOW WILL CARRY AN 
ISOLATED POP TO ACCOUNT ESSENTIALLY FOR THIS UNCERTAINTY...BUT 
EXPECT MAIN ROUND OF STORMS WOULD OCCUR AFTER 21Z AND INTO THE 
EVENING.  DOWNSIDE TO THIS SOLUTION IS THAT TEMPERATURES ARE LIKELY 
TO SOAR WELL INTO THE 90S EVEN APPROACHING 100 OUT WEST.  THIS 
LEAVES SOUNDINGS WITH DRY INVERTED V CONDITIONS BELOW 10KFT...AND 
STRENGTHENING MID LEVEL FLOW BRINGS A SHEAR COMPONENT TO THE STORMS 
NOT SEEN IN PREVIOUS DAYS OF GENERALLY 30-40KTS.  PW VALUES REMAIN 
1.5 INCHES OR MORE AHEAD OF THE INCOMING FRONT...WHICH WOULD LEAVE 
PLENTY OF MOISTURE AVAILABLE TO EVAPORATE INTO THE LOW LEVELS AND 
BRING THE THREAT OF STRONG DAMAGING OUTFLOW WINDS. 


.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 334 PM CDT SUN JUL 21 2013

MONDAY EVENING THROUGH WEDNESDAY...

HIGHEST CHANCES FOR ISOLATED SEVERE STORMS WERE PROMINENT IN THE 
MONDAY EVENING TIME PERIOD AFT 0Z. AMPLE CONVERGENCE AND LIFT IS SEEN 
THROUGH H85 ALONG AND AHEAD OF THE SOUTHWARD MOVING FRONT. UNLIKE 
PREVIOUS EVENINGS...A CENTERED SOURCE OF LIFT WITH THE FRONT AND A 
VEERING LLJ WILL ACT TO HELP SUSTAIN UPDRAFTS OVERNIGHT.  

THE MAIN UPPER TROF SHOULD CLEAR TO THE SOUTHEAST OVER MISSOURI BY 
TUESDAY MORNING WITH POSSIBLE LINGERING ELEVATED SHOWERS AND STORMS 
ALONG THE SURFACE FRONT POSITIONED ACROSS EAST CENTRAL KS BY THIS 
TIME. STABLE AIR BEHIND THE FRONT SHOULD CLEAR THE CLOUD DECK OVER 
MUCH OF THE AREA FOR THE AFTERNOON. THIS CREATES ONCE AGAIN AN 
UNSTABLE AIRMASS AS SFC BASED CAPE VALUES RISE TO NEAR 3000 J/KG. 
VEERING WINDS WITH HEIGHT AND DECENT FLOW AT 500 MB SHOULD BRING 0-6 
KM EFFECTIVE SHEAR VALUES UP TO 40 KTS BY PEAK HEATING HOURS.  
CHANCES FOR DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS WERE KEPT  
TUESDAY AFTERNOON AS A RESULT. THE ONLY LIMITING FACTOR TO CONSIDER 
WILL BE THE LACK OF STRONG LIFT IN THE MID LEVELS DURING THE 
AFTERNOON. BELIEVE ONCE THE STRONGER SHORTWAVE TROF ARRIVES BY 
TUESDAY EVENING...THE AREA WILL SEE THE BEST CHANCE FOR SHOWERS AND 
THUNDERSTORMS FOR THE FORECAST PERIOD. MADE SOME CHANGES TO 
WEDNESDAY AFTERNOON AND REMOVED PRECIP CHANCES FOR MUCH OF THE AREA 
AS SUBSIDENCE RESIDES IN THE WAKE OF THE EXITING TROUGH. THERE IS A 
SLIGHT PROBABILITY OF STORMS REFORMING OVER EAST KANSAS WEDNESDAY AFTERNOON 
WHERE CONVERGENCE AT H85 LIES HOWEVER BELIEVE MOST AREAS SHOULD 
REMAIN DRY. IN TERMS OF TEMPERATURES FOR THE PERIOD...LITTLE CHANGES 
WERE MADE TO PREVIOUS TRENDS. TUESDAY LOOKS TO BE THE WARMEST DAY OF 
THE ENTIRE FORECAST PERIOD WITH HIGHS IN THE LOW 90S. STRONGER MID 
LEVEL FLOW ON WEDNESDAY BEHIND THE PASSING TROF SHOULD HELP TO COOL 
HIGHS SLIGHTLY INTO THE UPPER 80S.

WEDNESDAY EVENING THROUGH SUNDAY...

THE ACTIVE WEATHER PATTERN CONTINUES THURSDAY INTO THE WEEKEND AS 
NORTHWEST FLOW KEEPS MINOR SHORTWAVE TROFS TRANSLATING SOUTHEASTWARD 
THROUGH THE AREA. OVERALL CONSENSUS WITH GUIDANCE WAS TO KEEP MOST 
OF THURSDAY DRY BEFORE ANOTHER STRONG SHORTWAVE BRINGS OVERNIGHT 
CONVECTION INTO FRIDAY.  WITH NO WELL DEFINED WAVES COMING THROUGH 
FRIDAY ONWARD...CONFIDENCE IN PRECIPITATION CHANCES IS LOW.  
PLACEMENT OF THE TROF AXIS THROUGHOUT THIS PERIOD WILL DEPEND ON 
WHICH AREAS RECEIVE PRECIPITATION. AND WITH GUIDANCE STILL VARYING 
BETWEEN MODEL RUNS...IT SEEMED APPROPRIATE TO LEAVE 20-30 PERCENT 
POPS FRIDAY AND SATURDAY.

TEMPERATURES DURING THIS PERIOD ARE FORECAST TO BE WELL BELOW NORMAL 
AS A POTENT CLOSED TROUGH DIGS INTO THE MIDWEST REGION. THIS WILL 
HELP TO USHER COOLER AND DRIER AIR TO THE AREA. WITH DEWPOINTS IN 
THE 50S BY THE WEEKEND...CONDITIONS COULD BECOME PLEASANT WITH HIGHS 
ONLY REACHING THE LOW 80S THURSDAY THROUGH SUNDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1234 PM CDT SUN JUL 21 2013

MVFR CONDITIONS CONTINUE ANOTHER HOUR OR SO AS CIGS SLOWLY LIFT
WITH THE HEATING OF THE DAY. WILL KEEP VCTS NEAR FOE WITH THUNDER
TO THE SOUTH...WITH ONLY VCSH ELSEWHERE AT TIMES THIS AFTERNOON.
WILL KEEP AN EYE ON DEVELOPMENT BUT AT THIS TIME APPEARS BETTER
LIFT WILL BE SOUTH OF THE TERMINALS. MAY SEE SOME BR IN THE EARLY
MORNING HOURS AT TOP/MHK AND HAVE STARTED WITH A TEMPO GROUP FOR
THIS. 


&&

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

$$

SHORT TERM...CRAVEN
LONG TERM...BOWEN
AVIATION...67