000
ACUS11 KWNS 212155
SWOMCD
SPC MCD 212155
TXZ000-212330-

MESOSCALE DISCUSSION 0758
NWS STORM PREDICTION CENTER NORMAN OK
0455 PM CDT TUE MAY 21 2013

AREAS AFFECTED...PARTS OF E-CNTRL AND SERN TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 212155Z - 212330Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...A STRONG TO SEVERE STORM THREAT WILL PROBABLY MOVE INTO
PORTIONS OF E-CNTRL AND SERN TX THIS EVENING/TONIGHT.  ALTHOUGH
ISOLD LARGE HAIL/DMGG WINDS WILL BE THE PRIMARY THREATS...A TORNADO
IS ALSO POSSIBLE.

DISCUSSION...RADAR MOSAIC SHOWS AN EXTENSIVE SQUALL LINE FROM WRN AR
SWWD INTO N-CNTRL TX WITH SOME CELLULAR STORMS /INCLUDING THE BELL
COUNTY SUPERCELL/ ON THE SRN FRINGE OF THE LINE OF STORMS.
SUBJECTIVE SURFACE MESOANALYSIS SHOWS THE N-CNTRL TX PORTION OF THE
LINE JUXTAPOSED WITH THE COLD FRONT AND THEN EXTENDING SWWD OVER THE
TX HILL COUNTRY.  FARTHER E...A PRE-FRONTAL CONFLUENCE ZONE HAS
SERVED TO PREFERENTIALLY FAVOR CELLULAR DEVELOPMENT ON THE SRN
PORTION OF THE LINE WITH THE FRONTAL LIFT DISPLACED 1-2 COUNTIES
WEST.  SURFACE TEMPS HAVE WARMED TO NEAR 90 DEG F WITH DEWPOINTS
AROUND 70 DEG F...CONTRIBUTING TO A VERY UNSTABLE AIRMASS /2500-3000
MLCAPE PER OBJECTIVE ANALYSIS/.  THE KGRK VWP SHOWS 0-6 KM SHEAR /40
KT/ MORE THAN SUFFICIENT FOR ORGANIZED LINE SEGMENTS AND SUPERCELLS.
ALTHOUGH LOW LEVEL SHEAR IS MODEST /100 M2/S2 0-1 KM SRH/...A
TORNADO IS POSSIBLE...ESPECIALLY IF A MORE FAVORABLE CONVECTIVE MODE
CAN BE MAINTAINED AS STORMS MOVE INTO THE DISCUSSION AREA.

..SMITH/CORFIDI.. 05/21/2013

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

ATTN...WFO...LCH...SHV...HGX...FWD...EWX...

LAT...LON   30589692 31549540 30969430 30429698 30589692