• MESO: Mesoscale Discussion 0183

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Sat Mar 2 17:56:02 2024
    ACUS11 KWNS 021755
    SWOMCD
    SPC MCD 021755=20
    UTZ000-NVZ000-022030-

    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=20

    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 https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!_8QmlXzidl3kPPSFDRGltohYHu80P6L54W__4YDh6d_GjFM6gmDNcry5bFi9_O9rWCLvYDFD4= Q-xsiF-mhu_NS-pAlU$ for graphic product...

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

    LAT...LON 40701408 41461309 41391244 40731205 39441349 39441442
    39871463 40701408=20


    =3D =3D =3D
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