ZCZC SPCSWOMCD ALL
ACUS11 KWNS 100238 
SPC MCD 100238 
TXZ000-100445-

MESOSCALE DISCUSSION 0577
NWS STORM PREDICTION CENTER NORMAN OK
0938 PM CDT SAT MAY 09 2015

AREAS AFFECTED...PORTION OF WRN TO CNTRL TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 100238Z - 100445Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...SCATTERED TO NUMEROUS TSTMS ARE LIKELY TO DEVELOP THROUGH
MIDNIGHT AS THE PACIFIC COLD FRONT IMPINGES ON THE RETREATING
DRYLINE OVER THE ERN PERMIAN BASIN AND CONCHO VALLEY. LARGE HAIL
SHOULD BE THE PRIMARY HAZARD. POTENTIAL WW ISSUANCE MAY ALSO INCLUDE
REPLACING PORTIONS OF EXTENDED WW 149 THAT EXPIRES AT 04Z.

DISCUSSION...02Z SURFACE ANALYSIS PLACED THE RETREATING DRYLINE FROM
BREWSTER COUNTY TO NEAR SJT AND ABI. A SURGE OF NWLY SURFACE WINDS
HAS REACHED HOWARD TO PECOS COUNTY BEHIND A WEAK PACIFIC COLD FRONT.
IR SATELLITE IMAGERY CONFIRM INITIAL CONVECTIVE DEVELOPMENT OVER
PECOS COUNTY. WITH 40-KT LOW-LEVEL SELYS SAMPLED IN KDFX VWP
DATA...CONTINUED MOIST ADVECTION FROM THE EDWARDS PLATEAU/BIG
COUNTRY/LOWER RIO GRANDE VALLEY IN CONJUNCTION WITH CONVERGENCE
ALONG THE FRONT SHOULD RESULT IN DEEP CONVECTION BLOSSOMING THROUGH
MIDNIGHT. STEEP MID-LEVEL LAPSE RATES AND STRONG EFFECTIVE SHEAR
WILL FAVOR LARGE HAIL PRODUCTION...SOME OF WHICH MAY BE SIGNIFICANT
ESPECIALLY IN THE FIRST HOUR OR TWO AFTER INITIATION.
CONVECTION-ALLOWING GUIDANCE REMAINS QUITE CONSISTENT IN DEPICTING
RAPID CLUSTERING MODE WITH UPDRAFTS LIKELY GETTING UNDERCUT BY
COMPOSITE FRONT/OUTFLOW. THIS SHOULD TEND TO TEMPER THE OVERALL
SEVERE RISK OVERNIGHT.

..GRAMS/MEAD.. 05/10/2015

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

ATTN...WFO...FWD...EWX...SJT...MAF...

LAT...LON   30640240 31210180 31800113 32090052 32519994 32599929
            32469857 32209811 31939831 31559900 30859979 30140128
            30070215 30270244 30640240 

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