MESO: Mesoscale Discussion 1917

ACUS11 KWNS 272045
SWOMCD
SPC MCD 272044
KSZ000-OKZ000-TXZ000-272245-

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

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

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

LAT...LON 34430235 38650059 39459967 38579926 34330063 34430235

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