ZCZC SPCSWOMCD ALL
ACUS11 KWNS 121853 
SPC MCD 121853 
WYZ000-IDZ000-UTZ000-MTZ000-NVZ000-ORZ000-122100-

MESOSCALE DISCUSSION 0628
NWS STORM PREDICTION CENTER NORMAN OK
0153 PM CDT TUE MAY 12 2015

AREAS AFFECTED...PORTIONS OF SRN ID...FAR NERN NV...FAR NRN UT...FAR
WRN WY

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 121853Z - 122100Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...THUNDERSTORMS HAVE DEVELOPED IN THE HIGH TERRAIN AND WILL
EXPAND IN COVERAGE IN THE NEXT FEW HOURS. LOCALLY DMGG WIND GUSTS
AND MARGINALLY SEVERE HAIL ARE POSSIBLE BUT A WATCH IS NOT
ANTICIPATED AT THIS TIME.

DISCUSSION...THUNDERSTORMS ARE DEVELOPING ON THE HEATED HIGH TERRAIN
IN THE MCD AREA INVOF AN INVERTED TROUGH EMANATING FROM A SURFACE
LOW PRESSURE AREA OVER CENTRAL NV. BOUNDARY-LAYER MOISTURE IS
SOMEWHAT HIGHER THAN FORECAST BY THE 12Z NAM AND RECENT RAP
RUNS...ESPECIALLY FROM THE SNAKE-RIVER VALLEY EWD INTO SERN
ID...WHERE SURFACE DEWPOINTS HAVE HELD IN THE MID- TO UPPER 40S OVER
MUCH OF THE AREA. MID-LEVEL LAPSE RATES OF 7.5 TO 8.0 C/KM AND VERY
STEEP LOW-LEVEL LAPSE RATES IN THE MODESTLY MOIST BOUNDARY LAYER
WILL SUPPORT SCATTERED THUNDERSTORMS CAPABLE OF LOCALLY-DMGG WIND
GUSTS AND MARGINALLY SEVERE HAIL. WIND SHEAR IN THE CLOUD-BEARING
LAYER OF 35-45 KT COULD SUPPORT LINEAR OR SMALL BOWING LINE SEGMENTS
WHERE COLD POOLS CONSOLIDATE...WHICH WOULD LOCALLY ENHANCE THE
SEVERE WIND THREAT. A WW IS NOT LIKELY AT THIS TIME BUT TRENDS WILL
CONTINUE TO BE MONITORED.

..CONIGLIO/COHEN/CORFIDI.. 05/12/2015

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

ATTN...WFO...RIW...TFX...SLC...PIH...MSO...BOI...LKN...PDT...

LAT...LON   41631220 41561290 41621402 41781568 42281633 43181706
            43821762 44711834 45011806 45381762 45701729 45861610
            45841427 45271260 44391159 43611078 43341058 42801040
            42261086 41811163 41631220 

NNNN