ZCZC SPCSWOMCD ALL
ACUS11 KWNS 200038 
SPC MCD 200038 
SDZ000-MTZ000-WYZ000-200145-

MESOSCALE DISCUSSION 1077
NWS STORM PREDICTION CENTER NORMAN OK
0738 PM CDT FRI JUN 19 2015

AREAS AFFECTED...SERN MT / NERN WY / WRN SD

CONCERNING...TORNADO WATCH 314...

VALID 200038Z - 200145Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 314 CONTINUES.

SUMMARY...INITIALLY DISCRETE SEVERE STORMS WILL LIKELY GROW UPSCALE
LATER THIS EVENING AS THE LLJ STRENGTHENS OVER THE NRN PLAINS.

DISCUSSION...SUBJECTIVE SURFACE MESOANALYSIS PLACES A LOW OVER NERN
WY WITH A COMPOSITE FRONT/COLD POOL SERVING AS AN EFFECTIVE FRONT
WHICH EXTENDS FROM NWRN ND INTO EXTREME SERN MT AND EXTENDING WWD
NEAR THE WY/MT BORDER.  MID TO UPPER 60S DEWPOINTS ARE LOCATED OVER
WRN SD AHEAD OF ONGOING QUASI-DISCRETE SUPERCELL ACTIVITY OVER THE
MT/WY/SD BORDER REGION.  A RECENT GIANT HAIL REPORT IN EXCESS OF 4
INCHES WAS REPORTED AT 2345Z WITH THE CARTER COUNTY MT SUPERCELL. 
SUPERCELL TORNADO POTENTIAL APPEARS PRIMARILY CONFINED TO THE WARM
SECTOR NEAR THE MT/WY/SD AND LOCALES DOWNSTREAM OVER THE NEXT 1 TO
PERHAPS 3 HOURS.  MAINLY A LARGE HAIL/SEVERE WIND GUST RISK WILL
ACCOMPANY THE STORMS TO THE N OF THE EFFECTIVE FRONT OVER ROSEBUD AN
POWDER RIVER COUNTIES.  

THE 00Z RAP SOUNDING SHOWED AN 8.6 DEG H7-H5 LAPSE RATE AND WIND
PROFILE STRONGLY SUPPORTIVE OF SUPERCELLS.  HOWEVER...AS A SLY LLJ
STRENGTHENS TO 50 KT TOWARDS MID EVENING OVER SD/NEB AND FURTHER
COALESCING OF CONVECTIVE OUTFLOW OCCURS...A TRANSITION TO AN
ORGANIZED LINEAR SYSTEM SHOULD TAKE PLACE IN THE 02-04Z PERIOD OVER
NWRN SD.  IN ADDITION TO SOME LARGE HAIL THREAT WITH THE ANCHORING
UPDRAFT IN THE EVOLVING LINE...A HIGHER-END SEVERE WIND GUST RISK
SEEMS POSSIBLE /65-90 MPH WINDS/ IF STORMS CAN DEVELOP INTO A BOW
ECHO.

..SMITH.. 06/20/2015

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

ATTN...WFO...ABR...UNR...BYZ...RIW...

LAT...LON   44530694 45420752 46060682 45630444 45850286 45640124
            43410137 44530694 

NNNN