• MESO: Mesoscale Discussion 1844

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Tue Aug 6 17:07:38 2024
    ACUS11 KWNS 061707
    SWOMCD
    SPC MCD 061706=20
    NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-061830-

    Mesoscale Discussion 1844
    NWS Storm Prediction Center Norman OK
    1206 PM CDT Tue Aug 06 2024

    Areas affected...Portions of eastern Pennsylvania...New Jersey...far
    eastern Maryland...northern Delaware

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

    Valid 061706Z - 061830Z

    Probability of Watch Issuance...80 percent

    SUMMARY...The severe threat should increase through the afternoon,
    with multiple rounds of strong to severe thunderstorms expected.
    Damaging gusts are the main threat, though a couple instances of
    large hail or a tornado are also possible. A Severe Thunderstorm
    Watch issuance will eventually be needed.

    DISCUSSION...Multiple semi-discrete, robust updrafts (including
    supercells) have become established over western PA and are poised
    to track eastward through the afternoon. However, before these
    storms cross the Appalachians, at least scattered thunderstorms are
    expected to develop east of the Appalachians amid a destabilizing
    airmass. Visible satellite shows a rapidly expanding CU field, with
    MRMS mosaic radar data showing convective initiation potentially
    already underway. To the lee of the Appalachians, surface
    temperatures are already reaching 90 F amid 70+ F dewpoints,
    supporting 8 C/km boundary-layer lapse rates (per 16Z mesoanalysis).
    Though deep-layer shear should remain modest through at least early
    to mid afternoon (i.e. around 30 kts effective bulk shear), the
    steepening low-level lapse rates will support a damaging gust
    threat.

    Later this afternoon, as the stronger storms to the west approach
    the region, an instance or two of large hail and maybe even a
    tornado could occur as these storms traverse a baroclinic boundary,
    where low-level shear may be locally maximized. A Severe
    Thunderstorm Watch will be needed soon to address the impending
    severe threat.

    ..Squitieri/Hart.. 08/06/2024

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!9bKktMADom11jK1qs1ViuKfnMCxMSeV5azDtRMg-hqKopu_MclnAPPv6EMZwklCjjbj00TRRA= wqgbZ5P8JWBWrzsng8$ for graphic product...

    ATTN...WFO...OKX...PHI...BGM...CTP...LWX...

    LAT...LON 41547634 41337471 41107410 40487393 39777413 39157450
    39087501 39117540 39457603 40057578 40817586 41547634=20


    =3D =3D =3D
    To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

    --- SBBSecho 3.20-Linux
    * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)