• MESO: Mesoscale Discussion 1906

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Thu Aug 15 15:57:50 2024
    ACUS11 KWNS 151557
    SWOMCD
    SPC MCD 151557=20
    MEZ000-MAZ000-NHZ000-RIZ000-VTZ000-CTZ000-NYZ000-151830-

    Mesoscale Discussion 1906
    NWS Storm Prediction Center Norman OK
    1057 AM CDT Thu Aug 15 2024

    Areas affected...New Hampshire...Vermont...into
    Massachusetts...eastern New York State...Connecticut and Rhode
    island

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

    Valid 151557Z - 151830Z

    Probability of Watch Issuance...5 percent

    SUMMARY...Increasing thunderstorm development appears probable
    through 3-5 PM EDT, with widely scattered stronger storms
    accompanied by a risk for localized, potentially damaging,
    downbursts and perhaps some small hail.

    DISCUSSION...Boundary-layer destabilization is underway across much
    of western New England into the Adirondacks and Catskills, with
    continuing insolation beneath the western flank of a modest
    mid-level cold pool associated with a slowly moving mid/upper trough
    near the Atlantic Seaboard. Forcing for ascent, associated with one
    or two perturbations pivoting through this regime, has been
    supporting some thunderstorm activity spreading southward within
    generally light (10-20 kt) northerly deep-layer mean flow across
    western Maine, with consolidating surface outflow slowly beginning
    to spread southwestward into western New England.

    With further boundary-layer destabilization, which may include CAPE
    increasing up to 1500+ J/kg, and weakening of mid-level inhibition,
    model output suggests that the outflow boundary, and orographic
    forcing along the higher terrain to the west, will provide a focus
    for increasing thunderstorm development through 19-21Z. Despite
    the weak nature of the wind fields and shear, modestly steep lower/mid-tropospheric lapse rates evident in forecast soundings may
    allow for sufficient negative buoyancy in downdrafts to support
    localized damaging surface gusts in stronger storms. Some small to
    marginally severe hail might also not be out of the question.

    ..Kerr/Thompson.. 08/15/2024

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!6-thxRO5xoOAxOp0de8M0a3SI2cOAjAyyrdeL72KeXSkN5dLD9fncBEQkj-aIKvYofABx4GHR= p6cltRT_notr7TvkeA$ for graphic product...

    ATTN...WFO...GYX...BOX...BTV...ALY...

    LAT...LON 45807107 44967115 44277135 43307060 42117106 41917201
    42197395 43337459 44067379 44887299 45287238 45807107=20


    =3D =3D =3D
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