283
ACUS11 KWNS 041821
SWOMCD
SPC MCD 041820
WYZ000-UTZ000-IDZ000-NVZ000-042015-

Mesoscale Discussion 1561
NWS Storm Prediction Center Norman OK
0120 PM CDT Fri Jul 04 2025

Areas affected...Northern Utah into western Wyoming

Concerning...Severe potential...Watch unlikely

Valid 041820Z - 042015Z

Probability of Watch Issuance...20 percent

SUMMARY...Thunderstorms developing from northern Utah into western
Wyoming will pose a severe wind risk through the afternoon and
evening hours. Watch issuance is currently not anticipated due to
relatively limited coverage of severe storms.

DISCUSSION...Steady vertical development of agitated cumulus and
cooling cloud-top temperatures within a few deeper convective towers
is noted in latest GOES visible/IR imagery across northern UT,
southwest WY, and far southeast ID. Ahead of this activity,
temperatures are slowly warming as dewpoints fall into the low
50s/upper 40s amid increasing boundary-layer mixing. Despite steep
mid-level lapse rates (as sampled by the 12 UTC SLC sounding) over
the region, vertical mixing of low-level moisture will largely limit
buoyancy values through the afternoon with MLCAPE expected to only
reach around 500-750 J/kg. However, deep mixing through roughly 500
mb and dry boundary-layer conditions will facilitate downdraft
accelerations within any deeper convective cores. Additionally,
30-35 knot mid-level flow will support modest, but adequate, bulk
wind shear through the CAPE-bearing layer to promote some degree of
storm organization and longevity. Initially isolated convection may
see some degree of consolidation into one or two cold-pool-driven
clusters by late afternoon. The potential for severe gusts will
likely be maximized with such clusters - especially any clusters
that can develop across northern UT into southwest WY where diurnal
heating/boundary-layer mixing will be greatest. However, the modest
thermodynamic and kinematic environments should limit the overall
number/coverage of severe storms, and limits confidence in the need
for a watch.

..Moore/Mosier.. 07/04/2025

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

ATTN...WFO...RIW...GJT...SLC...PIH...LKN...

LAT...LON   41151422 41231414 41871286 42461205 43031146 43681098
            44041059 44161026 44120927 43750856 43190825 42610817
            41990841 41270897 40920957 40011352 40081388 40281414
            40761433 41151422

MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN