ZCZC SPCSWOMCD ALL ACUS11 KWNS 210005 SPC MCD 210005 NEZ000-KSZ000-COZ000-210130- MESOSCALE DISCUSSION 1099 NWS STORM PREDICTION CENTER NORMAN OK 0705 PM CDT FRI JUN 20 2014 AREAS AFFECTED...WRN AND CNTRL NEB...NWRN KS...FAR NERN CO CONCERNING...SEVERE THUNDERSTORM WATCH 336... VALID 210005Z - 210130Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 336 CONTINUES. SUMMARY...SEVERE THUNDERSTORM THREAT CONTINUES IN AND NEAR THE WRN PART OF WW 336. THE STRONGEST ACTIVITY IS EXPECTED ACROSS THE I-80 CORRIDOR FROM GRI TO LBF...WHERE A THREAT FOR VERY LARGE HAIL WILL CONTINUE FOR THE NEXT 1-2 HRS. DISCUSSION...INTENSE THUNDERSTORMS ARE ONGOING ACROSS THE I-80 CORRIDOR FROM CENTRAL INTO WRN NEB...WITH GOLFBALL-SIZE HAIL RECENTLY REPORTED NEAR LBF AND 3-INCH HAIL REPORTED W OF GRI. THESE STORMS ARE SITUATED BETWEEN A WEAK WARM FRONT RUNNING FROM N-CNTRL NEB INTO THE NEB PANHANDLE AND A SFC TROUGH SITUATED JUST SOUTH OF THE I-80 CORRIDOR. THE LATTER FEATURE SEPARATES A HOT...WELL-MIXED AIRMASS TO THE SOUTH OF THE BOUNDARY FROM A VERY MOIST AND UNSTABLE AIRMASS TO THE NORTH OF THE BOUNDARY AND SOUTH OF THE WARM FRONT. RECENT MESOANALYSIS INDICATES MLCAPE OF 3000-3500 J/KG ALONG THE I-80 CORRIDOR...WITH BACKED LOW-LEVEL WINDS IN THIS REGION CONTRIBUTING TO EFFECTIVE HELICITY OF 200-300 M2/S2...DESPITE GENERALLY WEAK WINDS ALOFT. VERY LARGE HAIL WILL CONTINUE TO BE POSSIBLE FOR THE NEXT 1-2 HRS BEFORE NOCTURNAL STABILIZATION COMMENCES. NORTH OF THE MOST INTENSE ACTIVITY...TCU HAS BEEN NOTED ALONG THE WARM FRONT...BUT WITH THE BEST LOW-LEVEL MOISTURE SITUATED TO THE SOUTH...CONVECTIVE INITIATION HAS THUS FAR BEEN SUPPRESSED AND THE WINDOW OF OPPORTUNITY IS CLOSING FOR DEEP CONVECTION TO DEVELOP. MEANWHILE...SOUTH OF THE SOUTHERN BOUNDARY WHERE THE BOUNDARY LAYER RELATIVELY HOT AND DRY...CONVECTION HAS NOT BEEN AS WELL-ORGANIZED ACROSS NWRN KS...BUT A LOCALIZED THREAT OF DAMAGING WIND AND MARGINALLY SEVERE HAIL WILL PERSIST FOR THE NEXT 1-2 HRS BEFORE BOUNDARY-LAYER STABILIZATION BEGINS IN EARNEST. ..DEAN.. 06/21/2014 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...OAX...GID...LBF...GLD...BOU...CYS... LAT...LON 38980136 39150232 39840322 40670346 41730299 42670149 42880013 42629894 42399859 41629828 40849817 39929852 39589944 39210041 39020105 38980136 NNNN