ZCZC SPCSWOMCD ALL ACUS11 KWNS 061803 SPC MCD 061803 TXZ000-OKZ000-062000- MESOSCALE DISCUSSION 0515 NWS STORM PREDICTION CENTER NORMAN OK 0103 PM CDT WED MAY 06 2015 AREAS AFFECTED...PORTIONS OF WEST TEXAS...NORTHWEST TEXAS AND SOUTHWEST OKLAHOMA CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 061803Z - 062000Z PROBABILITY OF WATCH ISSUANCE...95 PERCENT SUMMARY...THUNDERSTORMS EXPECTED TO DEVELOP RAPIDLY BETWEEN 18 AND 19Z. SEVERE HAIL AND WIND GUSTS ARE THE PRIMARY THREATS INITIALLY...BUT TURNING LOW-LEVEL HODOGRAPHS SUGGEST A TORNADO THREAT FOR ANY SUSTAINED UPDRAFTS. DISCUSSION...STRONG HEATING HAS CONTRIBUTED TO RAPID DESTABILIZATION AHEAD OF A DIFFUSE DRYLINE WITH AN EASTERN EDGE STRETCHING FROM EAST OF LBB TO NEAR SHAMROCK. ALTHOUGH THE MCD AREA IS UNDER NEUTRAL TO SLIGHT MID-LEVEL HEIGHT RISES IN THE WAKE OF THE EXITING WAVE...LITTLE TO NO CONVECTIVE INHIBITION IS PRESENT OVER THE AREA. MIXED-LAYER CAPE VALUES HAVE RISEN ABOVE 2000 J/KG WITH LOW-LEVEL LAPSE RATES ABOVE 8 C/KM. WITH EFFECTIVE SHEAR OF 30-40 KT...SUPERCELL STRUCTURES WILL BE THE FAVORED MODE FOR PERSISTENT UPDRAFTS...BUT LONGEVITY OF THE SUPERCELLS COULD BE NEGATIVELY IMPACTED BY STORM INTERACTIONS AS NUMEROUS STORMS ARE EXPECTED TO DEVELOP UNDER LITTLE INHIBITION AND POSSIBLY ENHANCED BY LIFT FROM A WEAK POTENTIAL VORTICITY ANOMALY PROGRESSING THROUGH THE BROAD CYCLONIC FLOW IN UPPER-LEVELS. REGARDLESS OF STORM MODE...SEVERE HAIL IS LIKELY WITH THE STRONGER STORMS...WITH SEVERE WIND GUSTS POSSIBLE GIVEN THE STEEP LOW-LEVEL LAPSE RATES. ALTHOUGH LOW-LEVEL WIND SPEEDS REMAIN SOMEWHAT MODEST...LOW-LEVEL HODOGRAPHS SHOW CURVATURE...WITH EFFECTIVE HELICITY VALUES OF 100-150 M2/S2 FOR STORMS THAT DEVIATE TO THE RIGHT OF THE MEAN FLOW AND SHEAR. ..CONIGLIO/HART.. 05/06/2015 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FWD...OUN...SJT...LUB...AMA...MAF... LAT...LON 33749772 33359780 32599836 32419910 32660036 33390127 34170062 34380046 34920010 35239945 35019826 34629758 33749772 NNNN