Hail and Damaging Winds in Kansas, June 20, 2011

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1247 PM CDT MON JUN 20 2011

...UPDATE TO AVIATION...

.DISCUSSION...
SHORT TERM (TODAY AND TONIGHT)...

THE CONCERN FOR THE SHORT TERM FORECAST WILL BE ANOTHER ROUND OF
POTENTIAL SEVERE WEATHER WHICH COULD AFFECT PORTIONS OF CENTRAL AND
NORTHEAST KANSAS ON MONDAY AFTERNOON...

THE 8Z WATER VAPOR IMAGERY AND ASSOCIATED RUC ANALYSIS SHOWS A
CLOSED MID/UPPER LEVEL TROUGH CURRENTLY POSITIONED OVER WESTERN
COLORADO. THIS POTENT WAVE WILL EJECT INTO THE CENTRAL PLAINS
OVERNIGHT AND PUSH INTO THE CENTRAL AND NORTHERN PLAINS DURING THE
DAY ON MONDAY. AT THE SURFACE THE TROUGH ASSOCIATED WITH THE MID
LEVEL WAVE HAS ALREADY UNDERGONE LEE-SIDE CYCLOGENESIS AND
CURRENTLY SITS POSITIONED IN SW KANSAS NEAR KGCK. AHEAD OF THE
TROUGH STRONG SOUTHERLY FLOW WILL KEEP THE CONVEYOR BELT OF WARM
MOIST AIR COMING INTO NORTHEAST KANSAS. AS THE SURFACE TROUGH
CREEPS EASTWARD THE DRIER SWLY FETCH WILL THEN ENCROACH INTO THE
AREA DURING THE AFTERNOON. EXPECT TEMPERATURES IN THE WEST CENTRAL
ZONES TO GET VERY WARM AS HIGHS MAY GET INTO MID 90S. ALTHOUGH MID
LEVEL TEMPERATURES WILL BE VERY WARM AND WILL LEND TO CAPPING
CONCERNS THE STRONG SURFACE HEATING AND DRY AIR PUNCH SHOULD LEAD
TO STEEP LAPSE RATES THAT WOULD CAUSE THE CAP TO ERODE BY THE
LATE AFTERNOON. THUS GIVEN THE STRONG CONVERGENCE ALONG THE PSEUDO DRY-
LINE/COLD FRONT AND STRONG SURFACE HEATING AHEAD OF THE DL/CF
EXPECT SOME ISOLATED THUNDERSTORMS TO FORM LATE THIS AFTERNOON.
GIVEN THE HIGH DEWPOINT DEPRESSIONS ALONG THE DL INTERFACE EXPECT
THESE STORMS TO BE HIGH BASED...THUS MITIGATING MUCH OF THE
TORNADO THREAT. HOWEVER WITH AROUND 3000 J/KG TO WORK WITH AND
APPROXIMATELY 50 KTS OF DEEP LAYER SHEAR ANY STORM WHICH GETS
GOING ACROSS CENTRAL KANSAS WOULD QUICKLY BECOME SEVERE. THE LARGE
DEWPOINT DEPRESSION WILL LEAD TO INVERTED V SOUNDINGS IN THE
CONVECTIVE ENVIRONMENT INDICATING A STRONG THREAT FOR DAMAGING
WIND GUSTS. HAIL WILL ALSO BE A CONCERN GIVEN THE UNSTABLE
ENVIRONMENT. ACROSS THE NORTHERN ZONES...MODELS STILL HAVING A
HARD TIME GETTING A HANDLE ON THE EXACT LOCATION OF THE WARM FRONT
WHICH LOOKS LIKE IT WILL POSITION IT SELF SOMEWHERE IN SOUTHERN
NEBRASKA. SHOULD THE WARM FRONT BECOME POSITIONED NEAR THE KS/NE
BORDER THE ENHANCED LOW LEVEL SHEAR CAUSED BY THE ESE FLOW WILL
INTRODUCE A THREAT FOR AN ISOLATED TORNADO WITH ANY STORM THAT
MAY ENCOUNTER THE BOUNDARY. MONDAY NIGHT WILL SEE AN INCREASED
COVERAGE IN THUNDERSTORM ACTIVITY AS THE FRONTAL BOUNDARY SPEEDS
THROUGH THE AREA. EXPECT THESE STORMS TO BE STRONG TO SEVERE AS
THEY PUSH THROUGH THE AREA WITH STRONG DAMAGING WINDS AND LARGE
HAIL BEING THE PRIMARY THREATS.

TUESDAY THROUGH SUNDAY...

BY EARLY TUESDAY THE FRONTAL BOUNDARY WILL HAVE MADE IT COMPLETELY
THROUGH THE CWA LENDING TO DRIER AND COOLER CONDITIONS FOR TUESDAY
THROUGH MUCH OF THE REST OF THE WEEK. RETURN FLOW AT THE SURFACE
WILL ALLOW CONDITIONS TO BECOME WARMER AND MOISTER AS A WESTERN
RIDGE BUILDS IN CAUSING NORTHWESTERLY FLOW TAKES HOLD OF THE AREA.
THE LATE PART OF THE WORK WEEK THROUGH NEXT WEEKEND WILL BECOME
ACTIVE WITH MULTIPLE ROUNDS OF CONVECTIVE ACTIVITY AS SUBTLE
SHORTWAVE TROUGHS RIDE OVER THE RIDGE.

JL

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

&&

.AVIATION...

VFR CONDITIONS EXPECTED OUTSIDE OF CONVECTION. TIMING OF
CONVECTION IS A BIT TRICKY BUT MORE CONFIDENT IN THE 23Z-03Z
PERIOD AT MHK AND FROM 01Z-05Z AT TOP AND FOE ATTM. WINDS TO
REMAIN SOUTH TO SOUTH SOUTHWEST THROUGH THE PERIOD WITH SPEEDS
AROUND 14 KTS WITH HIGHER GUSTS. ALSO VSBYS SHOULD LOWER TO MVFR
IN THE TSRA ALSO GUSTS MAY EXCEED 45 KTS WITH THE TSRA.

53

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR KSZ037-054>056-058-059.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TOPEKA KS
341 PM CDT MON JUN 20 2011

KSZ008>012-020>024-026-034>040-054>056-058-059-212045-
REPUBLIC-WASHINGTON-MARSHALL-NEMAHA-BROWN-CLOUD-CLAY-RILEY-
POTTAWATOMIE-JACKSON-JEFFERSON-OTTAWA-DICKINSON-GEARY-MORRIS-
WABAUNSEE-SHAWNEE-DOUGLAS-LYON-OSAGE-FRANKLIN-COFFEY-ANDERSON-
341 PM CDT MON JUN 20 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL...NORTH
CENTRAL AND NORTHEAST KANSAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

THUNDERSTORMS WILL BE LIKELY LATE THIS AFTERNOON AND EVENING
ACROSS THE OUTLOOK AREA. THE STORMS THAT DEVELOP WILL BE STRONG TO
SEVERE. LARGE HAIL...DAMAGING WINDS AND TORNADOES ARE ALL POSSIBLE.

STRONG WINDS OF 25 TO 35 MPH WILL CONTINUE ACROSS EAST CENTRAL KANSAS
UNTIL EARLY EVENING WITH GUSTS AROUND 45 MPH.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

SCATTERED THUNDERSTORMS WILL BE POSSIBLE AGAIN ON TUESDAY. HOWEVER
THUNDERSTORM CHANCES WILL INCREASE AGAIN BY THE END OF THE WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL LIKELY BE NEEDED THROUGH THIS EVENING.