SPC MD 2056

SPC MD 2056


Mesoscale Discussion 2056
NWS Storm Prediction Center Norman OK
0332 PM CDT Sat Aug 26 2023

Areas affected…portions of eastern Oregon and south central Idaho

Concerning…Severe potential…Watch unlikely

Valid 262032Z – 262230Z

Probability of Watch Issuance…20 percent

SUMMARY…Isolated high-based strong to severe storms are possible
this afternoon and evening. Damaging gusts and small hail are
possible with the strongest storms. A WW is unlikely.

DISCUSSION…Across the northern Intermountain west, broad southerly
flow ahead of a mid-level trough was transporting monsoon moisture
northward into portions of eastern OR and southern ID. At the nose
of this surge, visible imagery showed new thunderstorm development
ongoing across parts of far northern NV/UT into southern ID. Clear
skies have allowed for strong diurnal heating and destabilization
with MUCAPE of 1000-15000 J/kg observed via SPC mesoanalysis. As
remaining inhibition is removed ahead of the northward lifting
trough, thunderstorms should continue to develop and mature through
the afternoon. Vertical shear of 30-35 kt should support some storm
organization/longevity into organized multicells and perhaps
transient supercell structures. Likely high based with LCLs near or
exceeding 2500 m, the primary risk will be damaging outflow gusts
from the more persistent storms. However, some small accumulating
hail may also be possible given relatively steep mid-level lapse
rates and the presence of a few longer-lived, and stronger updrafts.

The primary uncertainty with regard to the severe threat this
afternoon/evening is the coverage of severe storms. While a few
stronger updrafts are likely to evolve, broader synoptic forcing for
ascent is still relatively modest. This suggests a generally more
isolated threat related to individual storm evolution through much
of the day. Given this uncertainty, a new WW appears unlikely, but
convective trends will be monitored.

..Lyons/Thompson.. 08/26/2023

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


LAT…LON 44541421 43601328 43111328 42791353 42581434 42551518
42791597 43481753 43911823 44211862 44801846 45041784
45041672 44941587 44541421

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