Mesoscale Discussion 1936
   NWS Storm Prediction Center Norman OK
   0518 PM CDT Sat Aug 17 2024

   Areas affected...portions of northern California into western Oregon

   Concerning...Severe Thunderstorm Watch 631...

   Valid 172218Z - 172345Z

   The severe weather threat for Severe Thunderstorm Watch 631
   continues.

   SUMMARY...The severe threat continues across Severe Thunderstorm
   Watch 631. Damaging gusts and hail remain the primary concerns.

   DISCUSSION...Multiple rounds of strong, sustained thunderstorms
   continue to track north-northwestward in tandem with the stronger
   mid-level flow. The first round of thunderstorms in OR are comprised
   of a mix of multicells and transient supercells, likely producing at
   least small hail (per MRMS mosaic radar data). 6.5-7 C/km
   tropospheric lapse rates atop low 60s F dewpoints are contributing
   to over 500 J/kg MLCAPE, which may support a continued risk for
   strong wind gusts and hail.

   Farther south into northern CA, a 500 mb speed max is overspreading
   the area (per 22Z mesoanalysis), supporting locally stronger wind
   shear and the northward advection of steep mid-level lapse rates.
   Small but sustained supercell structures have become established in
   this area, likely accompanied by a hail threat. Steep low-level
   lapse rates and terrain influences are contributing to overlapping
   100+ J/kg 0-3 km CAPE and low-level vertical vorticity, which are
   also fostering supercell potential. However, 20-30 F T/Td spreads
   are common across northern CA, indicative of a well-mixed boundary
   layer supporting strong wind gusts, though a landspout can't be
   completely ruled out.

   ..Squitieri.. 08/17/2024

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

   ATTN...WFO...PDT...MFR...STO...PQR...EKA...

   LAT...LON   41072188 40382228 40192273 40252317 40552338 44422305
               45062274 45302239 45442194 45492128 45422111 45132103
               42792141 41072188