MESOSCALE DISCUSSION 1986
   NWS STORM PREDICTION CENTER NORMAN OK
   0238 PM CDT MON AUG 15 2011
   
   AREAS AFFECTED...SWRN MT...WRN WY...SERN ID...NRN UT
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 151938Z - 152145Z
   
   AN ISOLATED THREAT FOR DMGG WIND GUSTS WILL OCCUR THIS AFTERNOON.
   THE SPORADIC NATURE OF ANY OCCURRENCES OF DMGG WINDS IS EXPECTED TO
   PRECLUDE THE NEED FOR A WW.
   
   VISIBLE SATELLITE AND AREA RADAR IMAGERY DEPICT DEVELOPING
   CONVECTION OVER THE MOUNTAINS...WITH THE MOST VIGOROUS DEVELOPMENT
   FROM SW MT TOWARD THE TETON MOUNTAINS. CONVECTION WILL CONTINUE TO
   INCREASE IN COVERAGE/INTENSITY THROUGH THE AFTERNOON AS MID-LEVEL
   ASCENT ATTENDANT TO A PROGRESSIVE PV MAX SKIRTING THE INTERNATIONAL
   BORDER REGION PHASES WITH ASCENT OFFERED BY A LOWER-LATITUDE IMPULSE
   OVER THE GREAT BASIN. THE LATTER FEATURE IS FOLLOWED BY A MARKED DRY
   SLOT EVIDENT IN WATER VAPOR IMAGERY THAT IS CURRENTLY NOSING INTO
   SWRN ID...WITH AN ATTENDANT MID-LEVEL JET MAX -- SWLY FLOW OF 45-55
   KT IN THE 5-6-KM-AGL LAYER PER POCATELLO ID VWP DATA. THIS IS
   PROVIDING 25-40 KT OF EFFECTIVE BULK SHEAR ACROSS MUCH OF THE
   DISCUSSION AREA...WHICH COULD SUPPORT BRIEF ATTEMPTS AT CONVECTIVE
   ORGANIZATION AS THE AFOREMENTIONED ASCENT INTERACTS WITH OROGRAPHIC
   FORCING...LOW-LEVEL CONVERGENCE ASSOCIATED WITH A FRONT EXTENDING
   FROM SRN MT INTO SERN ID AND NRN UT...AND MLCAPE VALUES OF 500-1500
   J/KG. THE GREATEST INSTABILITY IS ANTICIPATED OVER PORTIONS OF NRN
   UT WHERE A PLUME OF SLIGHTLY RICHER BOUNDARY-LAYER MOISTURE -- I.E.
   SFC DEWPOINTS IN THE LOWER TO MIDDLE 50S -- EXISTS. THE PRIMARY
   CONCERN WITH THIS ACTIVITY WILL BE GUSTY WINDS...AND AN ISOLATED
   THREAT FOR DMGG WIND GUSTS WILL BE POSSIBLE GIVEN SFC T-TD SPREADS
   ALREADY REACHING 30F IN SOME OF THE LOWER ELEVATIONS. HOWEVER...WITH
   LIMITED PW VALUES ACROSS THE REGION /0.78 INCHES AND 0.98 INCHES PER
   12Z OBSERVED GREAT FALLS MT AND SALT LAKE CITY UT SOUNDINGS...
   RESPECTIVELY/...THE COVERAGE OF ANY SVR ACTIVITY IS EXPECTED TO BE
   MINIMAL.
   
   ..COHEN.. 08/15/2011
   
   
   ATTN...WFO...BYZ...RIW...GJT...TFX...SLC...PIH...MSO...
   
   LAT...LON   45830860 42970864 40900995 40181197 40381332 41031369
               42081269 42911208 43851188 44091253 43561378 43711438
               44401490 45551408 46641256 46841033 45830860