ZCZC SPCSWOMCD ALL ACUS11 KWNS 132037 SPC MCD 132037 TXZ000-OKZ000-132300- MESOSCALE DISCUSSION 0635 NWS STORM PREDICTION CENTER NORMAN OK 0337 PM CDT WED MAY 13 2015 AREAS AFFECTED...PORTIONS OF NORTHWEST TEXAS AND SOUTHWEST OKLAHOMA CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 132037Z - 132300Z PROBABILITY OF WATCH ISSUANCE...20 PERCENT SUMMARY...THE AREA IS BEING MONITORED FOR AN INCREASING RISK OF STRONG TO ISOLATED SEVERE THUNDERSTORMS...WHICH COULD CONTINUE INTO THE EVENING. WHILE CONVECTIVE TRENDS WILL BE MONITORED...WW ISSUANCE IS UNLIKELY. DISCUSSION...WATER VAPOR LOOPS INDICATE A MID-LEVEL DRY SLOT CURLING AROUND THE SRN/ERN SIDES OF A SHORTWAVE TROUGH ADVANCING NEWD ACROSS W TX/ERN NM. RELATED EROSION OF MULTI-LAYERED CLOUDS ASSOCIATED WITH EARLIER WIDESPREAD PRECIPITATION HAS GIVEN WAY TO AT LEAST PARTIAL CLEARING SW OF A COMPOSITE DIFFERENTIAL-HEATING/OUTFLOW BOUNDARY ANALYZED FROM N OF PLAINVIEW TO NEAR ABILENE TO E OF JUNCTION. THIS BOUNDARY WILL GRADUALLY EDGE NWD AS AN ISALLOBARIC RESPONSE TO 1.0-1.5 MB PER 2 HOURS PRESSURE FALLS ANALYZED TO ITS N...RELATED TO LARGE-SCALE ASCENT PRECEDING THE MID-LEVEL TROUGH. THE BAROCLINIC BOUNDARY INTERSECTS A LEE TROUGH N OF PLAINVIEW THAT EXTENDS SWD/SWWD INTO SWRN TX. STEEPENING LOW-LEVEL LAPSE RATES ON THE WARM SIDE OF THE BOUNDARY...AND ESPECIALLY W OF THE LEE TROUGH...WILL CONTINUE TO FACILITATE AN INCREASE IN CONVECTION. BANDED CU DEVELOPMENT HAS ALREADY BEEN NOTED NEAR AND W OF THE LEE TROUGH IN RELATIVELY DRIER AIR FROM WHICH DEEPER CONVECTION MAY BLOSSOM DURING THE NEXT FEW HOURS...ESPECIALLY AS DCVA OVERLIES THE REGION. CONVECTION MAY INTENSIFY AS IT SPREADS INTO THE SECTOR OF MARGINALLY BUOYANT AIR SUPPORTED BY INSOLATION AMIDST LOWER 60S SFC DEWPOINTS BETWEEN THE LEE TROUGH AND BAROCLINIC BOUNDARY. THE DYX VWP SAMPLES AROUND 35-40 OF DEEP SHEAR WITH A VEERING WIND PROFILE...WHICH MAY SUPPORT A FEW SUPERCELL STRUCTURES CAPABLE OF MARGINALLY SVR HAIL/WIND. A TORNADO CANNOT BE RULED OUT GIVEN THE LOW-LEVEL DIRECTIONAL SHEAR AIDED BY RELATIVELY BACKED SFC FLOW. SUCH ACTIVITY WILL SPREAD NEWD/EWD TOWARD THE LOW ROLLING PLAINS OF TX AND PERHAPS SW OK INTO THE EVENING. HOWEVER...ONLY MODEST MID-LEVEL LAPSE RATES...AND BACKING OF THE FLOW WITH HEIGHT ABOVE 6 KM AGL POTENTIALLY MITIGATING CONVECTIVE ORGANIZATION...CAST DOUBT ON THE OVERALL SVR RISK -- IN ADDITION TO THE NARROW SPATIAL EXTENT OF GREATER BUOYANCY. ..COHEN/CORFIDI.. 05/13/2015 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...OUN...SJT...LUB...AMA... LAT...LON 32830045 33130077 33700097 34290121 34920143 35200085 34909976 33419938 32889989 32830045 NNNN