• MESO: Mesoscale Discussion 1295

    From COD Weather Processor@1:2320/107 to wx-storm@lists.illinois.edu on Wed Jun 24 20:20:38 2026
    ACUS11 KWNS 242020
    SWOMCD
    SPC MCD 242020=20
    NEZ000-COZ000-WYZ000-242215-

    Mesoscale Discussion 1295
    NWS Storm Prediction Center Norman OK
    0320 PM CDT Wed Jun 24 2026

    Areas affected...Southeast Wyoming into northern Colorado and far
    western Nebraska

    Concerning...Severe potential...Watch likely=20

    Valid 242020Z - 242215Z

    Probability of Watch Issuance...80 percent

    SUMMARY...Thunderstorm development appears likely by late afternoon
    for southeast Wyoming and into the Colorado Front Range. Watch
    issuance will likely be needed as convection begins to intensify.

    DISCUSSION...Deepening cumulus is noted along the northern CO Front
    Range per recent GOES day cloud phase imagery with at least a couple
    of early, but transient, attempts a initiation noted near Castle
    Rock, CO and Cheyenne, WY. This activity is largely being driven by
    orographic ascent on the northeastern fringe of the low/mid-level
    thermal ridge in place from northern NM to northern CO where
    mid-level lapse rates are fairly steep, but capping is somewhat
    weaker. Additional attempts at initiation appear likely over the
    next 1-2 hours based on satellite trends, but lingering inhibition
    at lower elevation may preclude robust, self-sustained convection in
    the near term. However, continued daytime heating of a very moist
    air mass (dewpoints in the upper 50s/low 60s) will continue to erode
    inhibition and increase the probability for successful initiation
    either along the Front Range, off the Laramie Mountains, and/or
    along a weak cold frontal boundary draped from western NE into
    east-central WY. Latest CAM guidance and a recent ACARs sounding
    from Denver, CO suggest temperatures in the upper 70s to low 80s may
    be required for this to occur.=20

    Once deep convection can become established, it will mature within
    an environment favorable for splitting supercells given very
    elongated hodographs characterized by 50-60 knots of effective bulk
    shear. Southeasterly low-level flow across WY and into northern
    CO/western NE may support some tornado threat with any discrete
    right-moving supercell, but the more probable hazard will be severe
    gusts and very large hail - possibly as large as 2-4 inches in
    diameter. Watch issuance is expected once sustained convection
    becomes apparent.

    ..Moore/Guyer.. 06/24/2026

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!7mZJ6ZZYObdFYsD3vKW11Jdl2Ib29bWOVTo6_ihpO6ag5Qglqjj5q9c2H3zvBJX54bCzZK1tN= o-DFeGMYeReHrHHGk0$ for graphic product...

    ATTN...WFO...PUB...BOU...CYS...RIW...

    LAT...LON 39210538 39980535 40820552 41460599 42580666 42960673
    43230660 43360628 43380584 43280526 43120472 42850409
    42420376 41910349 40690316 40050308 39630316 39300342
    39030387 38980429 38950501 38990527 39210538=20

    MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
    MOST PROBABLE PEAK WIND GUST...65-80 MPH
    MOST PROBABLE PEAK HAIL SIZE...2.75-4.25 IN


    =3D =3D =3D
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