• MESO: Mesoscale Discussion 1204

    From COD Weather Processor@1:2320/107 to wx-storm@lists.illinois.edu on Fri Jun 19 20:21:27 2026
    ACUS11 KWNS 192021
    SWOMCD
    SPC MCD 192021=20
    NVZ000-CAZ000-192245-

    Mesoscale Discussion 1204
    NWS Storm Prediction Center Norman OK
    0321 PM CDT Fri Jun 19 2026

    Areas affected...Western Nevada and portions of far northeast
    California

    Concerning...Severe potential...Watch unlikely=20

    Valid 192021Z - 192245Z

    Probability of Watch Issuance...20 percent

    SUMMARY...The potential for strong to severe downburst winds will
    increase through early evening across far northeast California and
    into western Nevada. Watch issuance is not expected.

    DISCUSSION...Cumulus has slowly been deepening along the Sierra
    Nevada per GOES imagery as early-day clouds clear and diurnal
    heating/upslope flow gradually increases. Based on regional radar
    imagery, several of the deeper towers are beginning to produce
    downdrafts, and occasional lightning flashes have been noted in GLM
    data over the past 20-30 minutes. These trends confirm the presence
    of very meager, but sufficient, buoyancy to support convection. GOES water-vapor imagery also depicts a low-level trough pivoting
    northward into NV, which will likely aid in ascent away from the
    terrain as well as provide some degree of mid-level
    cooling/destabilization - both of which will be favorable for the
    maintenance of convection through the late afternoon hours. As
    convection spreads northeast over the lower terrain, downdrafts will
    encounter a very deeply-mixed boundary layer characterized by nearly
    dry adiabatic 0-3 km lapse rates. This will promote substantial
    evaporative cooling and downdraft accelerations favorable for strong
    to severe downburst winds at the surface. Recent CAM guidance
    highlights this potential well and suggests that gusts may be as
    high as 60-70 mph. Despite the potential for severe winds, limited
    buoyancy should modulate the lifespan and intensity of convective
    cells and negate the need for a watch.

    ..Moore/Hart.. 06/19/2026

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!_9mBTga5lg8mISlf2Izv3xbEzYrkT4ppDhfVfG2JuIisOWdyXMdiwXSxrYwmhMVp-fcnpm21i= xDDLfTwe7qHqluqAGw$ for graphic product...

    ATTN...WFO...LKN...REV...HNX...

    LAT...LON 38021931 38882005 39382027 39702038 40092038 40512015
    40791967 41011924 41011878 40911829 40711795 40011764
    39431773 38171862 38011879 37941908 38021931=20

    MOST PROBABLE PEAK WIND GUST...55-70 MPH


    =3D =3D =3D
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