Storm Prediction Center Mesoscale Discussion 1847

   Mesoscale Discussion 1847
   NWS Storm Prediction Center Norman OK
   0315 PM CDT Tue Aug 06 2024

   Areas affected...Western and Central Montana into Northern Wyoming

   Concerning...Severe potential...Watch possible 

   Valid 062015Z - 062245Z

   Probability of Watch Issuance...60 percent

   SUMMARY...A severe thunderstorm watch may be needed across portions
   of central and western Montana, as well as portions of northern
   Wyoming, later this afternoon or early evening... primarily for
   damaging winds and hail.

   DISCUSSION...Scattered convection has developed over portions of
   Idaho and Montana ahead of a mid-level shortwave trough, progressing
   eastward from OR/WA. Current SPC Mesoanalysis and forecast proximity
   soundings suggests that the ongoing convection in Montana is rooted
   above the boundary-layer, but may later become surface based as the
   boundary-layer continues to mix throughout the afternoon. Recent
   satellite trends suggests additional convective development over far
   eastern ID and western MT is likely, which will move eastward into
   central MT this afternoon and evening. Ongoing convection in far
   northwestern WY, where surface-based CINH has eroded, will also move
   eastward into north-central and northeastern WY. 

   Convection is expected to be high-based, with MLLCL heights ranging
   from 2-3 km in height due to modest dewpoints in the low-to-mid 50s
   F. However, MLCAPE values exceeding 1000 J/kg, coupled with
   deep-layer shear values between 35-45 kts (owing to mostly
   straight-line hodographs), will support organized convective
   clusters and high-based supercell thunderstorms. Due to the high
   based nature of convection, and relatively dry boundary layer
   profiles, damaging straight-line winds from thunderstorm outflow
   will be possible. Additionally, any organized supercells will be
   capable of large hail. A severe thunderstorm watch may be needed
   later this afternoon and into the evening.

   ..Halbert/Lyons/Hart.. 08/06/2024

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...UNR...BYZ...GGW...RIW...TFX...

   LAT...LON   45330964 46331172 46851245 47461289 48241276 48961261
               48981011 48950843 48330764 47280661 46380587 44630509
               44100523 43820565 43840640 44190723 44670814 45330964