• MESO: Mesoscale Discussion 0832

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Sun May 21 19:28:04 2023
    ACUS11 KWNS 211927
    SWOMCD
    SPC MCD 211927=20
    IDZ000-WAZ000-212130-

    Mesoscale Discussion 0832
    NWS Storm Prediction Center Norman OK
    0227 PM CDT Sun May 21 2023

    Areas affected...Northeast WA into the ID Panhandle

    Concerning...Severe potential...Watch possible=20

    Valid 211927Z - 212130Z

    Probability of Watch Issuance...40 percent

    SUMMARY...Scattered thunderstorm development is expected later this
    afternoon, with a threat for isolated severe hail and wind gusts.
    The need for watch issuance is uncertain at this time.

    DISCUSSION...Relatively strong diurnal heating is underway early
    this afternoon across parts of eastern WA into northern ID. With dew
    points in the low/mid 50s F amid warming temperatures, MLCAPE has
    already increased into the 500-1000 J/kg range, and some further destabilization is possible through the afternoon. Weak high-based
    convection is ongoing across east-central WA, which may be
    associated with a low-amplitude shortwave trough moving
    northeastward in advance of a stronger mid/upper-level shortwave
    approaching the Pacific Northwest coast. This area of ascent
    combined with decreasing MLCINH is expected to result in stronger
    thunderstorm development later this afternoon, with an east-west
    oriented surface boundary across northeast WA expected to be a
    primary focus for initiation.=20=20

    Increasing midlevel flow will support sufficient vertical shear for
    organized convection, especially near/north of the surface boundary,
    where backed low-level flow will result in larger effective shear
    magnitudes. A couple of supercells may evolve with time, posing a
    threat of large hail and localized severe gusts. Storm coverage
    south of the surface boundary is more uncertain, due to weaker
    low-level convergence and a tendency for low-level moisture to mix
    out with time.=20

    With northeasterly storm motions expected across the area, storms
    developing along the surface boundary and moving through the most
    favorable environment may quickly move across the international
    border into British Columbia. Due to the potentially limited
    spatiotemporal extent of the threat, the need for watch issuance is
    uncertain at this time.

    ..Dean/Grams.. 05/21/2023

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!_hz0Ke7flRihHlkqEGrWOLdo_fvgwlwaGE_lc8nbYbJVZDxhLAmOJ4vQxfnq-GCKEiRVQAb9m= 6vmeS4qfxsKOhV1vC4$ for graphic product...

    ATTN...WFO...OTX...

    LAT...LON 47721784 48081938 49051953 49301878 49241744 49131655
    48311641 47821701 47721784=20


    =3D =3D =3D
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