• MESO: Mesoscale Discussion 2259

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Wed Dec 11 08:15:45 2024
    ACUS11 KWNS 110815
    SWOMCD
    SPC MCD 110815=20
    MEZ000-111215-

    Mesoscale Discussion 2259
    NWS Storm Prediction Center Norman OK
    0215 AM CST Wed Dec 11 2024

    Areas affected...Southern Maine

    Concerning...Freezing rain=20

    Valid 110815Z - 111215Z

    SUMMARY...Light to moderate freezing rain appears likely through 12
    UTC across parts of southern Maine.

    DISCUSSION...Recent surface observations from southern ME have
    reported a wintry mix of light freezing rain and snow over the past
    hour as light precipitation migrates over the region. The 00 UTC GYX
    sounding sampled sub-freezing surface temperatures in the upper 20s
    with a 2 C warm nose at around 850 mb. This warm nose is expected to
    intensify through 12 UTC, amid strengthening low to mid-level warm
    air advection, within the warm conveyor belt of an intensifying
    cyclone. This should promote a change over from a wintry mix to
    predominantly liquid hydrometeors over the next couple of hours.=20

    Latest surface analyses/observations show the surface warm front
    remains well displaced to the south, so the shallow sub-freezing
    layer should remain in place through sunrise. Light precipitation
    should continue as isentropic ascent increases, but precipitation
    rates will increase closer to 10-12 UTC as a broader plume of
    stratiform rain (associated with deeper large-scale ascent and
    closer to the surface warm front) migrates from New England
    northeast into southern ME. It remains unclear how surface
    temperatures will respond as this precipitation approaches, given
    the coincident arrival of the surface warm front. However, latest
    high-res guidance suggests the sub-freezing layer will persist long
    enough to realize moderate freezing rain rates between 10-12 UTC,
    especially within deeper valleys.

    ..Moore.. 12/11/2024

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!4xkZXkLflEFi0oJGg0eGOuFhyDpwP_Jgt9iWHtVHZ9uRw6zpv1NXe4_LUKEaFQ8snfKMpX6I9= lNWnYhviJOyh2-tdBk$ for graphic product...

    ATTN...WFO...CAR...GYX...

    LAT...LON 43927097 44437066 44847012 45106936 45156876 45096831
    44936819 44696829 44626860 44386910 43996980 43727015
    43517051 43487072 43547087 43647093 43927097=20


    =3D =3D =3D
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