MESOSCALE DISCUSSION 1917
   NWS STORM PREDICTION CENTER NORMAN OK
   0344 PM CDT FRI SEP 27 2013

   AREAS AFFECTED...TX AND OK PANHANDLES THROUGH WRN KS

   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

   VALID 272044Z - 272245Z

   PROBABILITY OF WATCH ISSUANCE...40 PERCENT

   SUMMARY...STORMS ARE EXPECTED TO DEVELOP BY 22-23Z FROM THE TX
   PANHANDLE NWD INTO WRN KS. INITIAL STORMS MAY DEVELOP SOME SUPERCELL
   STRUCTURES WITH A FEW LINE SEGMENTS ALSO LIKELY. ISOLATED LARGE HAIL
   AND DAMAGING WIND GUSTS ARE EXPECTED TO BE THE PRIMARY THREATS
   THROUGH MID EVENING.

   DISCUSSION...RECENT OBSERVATIONS INDICATE LOW-MID 60S DEWPOINTS
   ADVECTING NWD THROUGH WRN TX WITH UPPER 50S EVIDENT FARTHER NORTH
   ACROSS WRN KS. STRONG DIABATIC WARMING IS OCCURRING FROM WRN TX NWD
   INTO PORTIONS OF WRN AND CNTRL KS EAST OF MID-LEVEL CLOUD DECK
   ASSOCIATED WITH A PLUME OF SUBTROPICAL MOISTURE. HOWEVER...MID-LEVEL
   LAPSE RATES ARE NOT PARTICULARLY STEEP DUE PRIMARILY TO A LAYER OF
   WARM AIR ABOVE A RELATIVELY SHALLOW ELEVATED MIXED LAYER. MUCAPE
   RANGES FROM 1000 J/KG IN THE TX PANHANDLE TO BELOW 500 J/KG OVER WRN
   KS. SATELLITE DATA INDICATE A SUBSTANTIAL INCREASE IN BOUNDARY LAYER
   CUMULUS OVER THE TX PANHANDLE AND MID-LEVEL CONVECTION APPEARS TO BE
   DEEPENING WITHIN THE SUBTROPICAL MOISTURE PLUME JUST NW OF LUBBOCK.

   AS UPPER TROUGH OVER THE CNTRL ROCKIES SHIFTS EWD TOWARD THE HIGH
   PLAINS...ZONE OF PRE-FRONTAL CONVERGENCE SHOULD INCREASE FROM WRN TX
   THROUGH WRN KS. STORMS ARE EXPECTED TO DEVELOP IN THE NEXT COUPLE
   HOURS WITHIN AXIS OF BOUNDARY LAYER DESTABILIZATION ALONG ERN FRINGE
   OF SUBTROPICAL MOIST PLUME. DEEP LAYER VERTICAL SHEAR WILL
   STRENGTHEN AS MID-LEVEL JET ROTATES THROUGH BASE OF UPPER TROUGH
   SUPPORTING 40-50 KT EFFECTIVE SHEAR FROM THE TX PANHANDLE INTO WRN
   KS. DESPITE A SOMEWHAT MODEST THERMODYNAMIC ENVIRONMENT A FEW STORMS
   MAY DEVELOP SUPERCELL CHARACTERISTIC...POSSIBLY EVOLVING INTO LINE
   SEGMENTS...POSING A THREAT FOR ISOLATED DAMAGING WIND AND LARGE
   HAIL.

   ..DIAL/THOMPSON.. 09/27/2013


   ATTN...WFO...OUN...GID...DDC...GLD...LUB...AMA...

   LAT...LON   34430235 38650059 39459967 38579926 34330063 34430235