SPC MD 183

[NorthGeorgiaWX]

MD 0183 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR THE GREAT SALT LAKE DESERT INTO WASATCH VICINITY

Mesoscale Discussion 0183
NWS Storm Prediction Center Norman OK
1155 AM CST Sat Mar 02 2024

Areas affected...the Great Salt Lake Desert into Wasatch vicinity

Concerning...Severe potential...Watch unlikely 

Valid 021755Z - 022030Z

Probability of Watch Issuance...20 percent

SUMMARY...Thunderstorm activity may overspread the region, including
much of the Salt Lake City area, through 2-3 PM MST, accompanied by
potentially damaging surface gusts, small hail, sharply reduced
visibilities and a changeover of precipitation to at least a brief
period of heavy snow.

DISCUSSION...Forecast soundings indicate thermodynamic profiles with
largely sub-freezing temperatures and/or wet-bulb temperatures
across the Great Salt Lake Desert into Wasatch vicinity, except for
initially a shallow near-surface layer over lower elevations.  With
insolation, a modestly deep and well-mixed boundary-layer appears to
be evolving in advance of an approaching cold front, with sufficient
moisture to support the development of weak boundary-layer based
CAPE.  With continuing insolation, further cooling aloft will
support additional destabilization through mid afternoon.

Deepening pre-frontal convective development, some of which has
begun to produce lightning, is already underway upstream in response
to the destabilization, aided by forcing for ascent ahead of
mid-level troughing overspreading much of the Great Basin and
Northwest.  One northeastward progressing embedded short wave
perturbation appears to passing near or to the northwest of the
Great Salt Lake, with another trailing to its southwest.  It appears
that associated forcing for ascent may be accompanied by a
developing cluster of convection with embedded thunderstorms
overspreading the Great Salt Lake Desert into Wasatch vicinity
through 20-22Z.

Beneath the exit region of a vigorous upper jet streak, Rapid
Refresh and NAM output indicate strong mean flow on the order of
45-50+ kt developing in the lowest few kilometers above
ground-level, both ahead and to the rear of the convection.  Coupled
with latent cooling in convective downdrafts, aided by melting small
hail or graupel, downward mixing of momentum may promote strong to
severe gusts reaching the surface.  This may also coincide with a
precipitation changeover from rain and graupel to at least a brief
period of heavy snow, contributing to sharply reduced visibilities
as surface temperatures cool to near freezing.

..Kerr/Hart.. 03/02/2024

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

ATTN...WFO...SLC...LKN...

LAT...LON   40701408 41461309 41391244 40731205 39441349 39441442
            39871463 40701408 

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