ZCZC SPCSWOMCD ALL ACUS11 KWNS 182356 SPC MCD 182356 MTZ000-190200- MESOSCALE DISCUSSION 0981 NWS STORM PREDICTION CENTER NORMAN OK 0656 PM CDT SAT JUN 18 2016 AREAS AFFECTED...MT CONCERNING...SEVERE THUNDERSTORM WATCH 271... VALID 182356Z - 190200Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 271 CONTINUES. SUMMARY...A THREAT FOR LARGE HAIL...WIND DAMAGE AND A TORNADO WILL INCREASE OVER THE NEXT FEW HOURS ACROSS NRN MT. DISCUSSION...LATEST SFC ANALYSIS SHOWS A 1007 MB LOW OVER SRN MT WITH AN AREA OF BACKED WINDS NORTH AND EAST OF THE LOW ACROSS MUCH OF NRN AND ERN MT. SCATTERED THUNDERSTORMS HAVE DEVELOPED OVER LAST COUPLE OF HOURS IN THE HIGHER TERRAIN OF WRN MT AND THIS ACTIVITY IS MOVING INTO AND ACROSS THE LOWER ELEVATIONS OF NRN MT. A SUPERCELL IS LOCATED ALONG THE LEADING EDGE AND IS APPROACHING HAVRE MT EARLY THIS EVENING. AHEAD OF THIS STORM...MODERATE INSTABILITY IS ANALYZED BY THE RAP IN MOST OF NERN MT WHERE 0-6 KM SHEAR IS ESTIMATED IN THE 60 TO 70 KT RANGE AND 700-500 MB LAPSE RATES ARE APPROACHING 8.0 C/KM. THIS ENVIRONMENT WILL CONTINUE TO SUPPORT SUPERCELL DEVELOPMENT WITH LARGE HAIL. HAILSTONES OF GREATER THAN 2 INCHES IN DIAMETER WILL BE POSSIBLE WITH THE MORE DOMINANT SUPERCELLS. LOW-LEVEL SHEAR IS ALSO FORECAST TO INCREASE OVER THE NEXT COUPLE OF HOURS WHICH WILL MAKE A TORNADO POSSIBLE AS WELL. A SEVERE THREAT MAY ALSO DEVELOP ACROSS SRN PARTS OF THE WATCH AS NEW CONVECTION INITIATES AND STRENGTHENS OVER THE NEXT FEW HOURS. ..BROYLES/THOMPSON.. 06/18/2016 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BYZ...GGW...TFX... LAT...LON 46900613 46870787 46730784 46760938 46670938 46710982 46781009 46691034 46751055 47021110 46981147 46931151 46911177 47111181 47161198 47261204 47561205 47561191 47611192 47611165 47731165 47731143 48201136 48221164 48321167 48471218 49021219 48990816 48990407 47370404 47370408 47350447 47520451 47530455 47580456 47600496 47700497 47680518 47800520 47790539 47180540 47180577 47090582 47080592 47170609 47060609 46870607 46900613 NNNN