• MESO: Mesoscale Discussion 2010

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Fri Aug 18 03:05:17 2023
    ACUS11 KWNS 180305
    SWOMCD
    SPC MCD 180304=20
    NYZ000-PAZ000-180600-

    Mesoscale Discussion 2010
    NWS Storm Prediction Center Norman OK
    1004 PM CDT Thu Aug 17 2023

    Areas affected...Parts of central/eastern PA and southern NY

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

    Valid 180304Z - 180600Z

    Probability of Watch Issuance...40 percent

    SUMMARY...The potential for damaging gusts and possibly a tornado or
    two should gradually increase during the next few hours, as a line
    of storms develops/spreads eastward.

    DISCUSSION...Latest water vapor imagery indicates a substantial
    midlevel trough moving eastward over the Great Lakes and Ohio River
    vicinity. Related large-scale ascent/midlevel height falls preceding
    this feature are gradually impinging on central PA/southern NY --
    where a north/south-oriented quasi-stationary baroclinic zone is
    evident. As the trough takes on a slight negative tilt and stronger
    height falls overspread the frontal zone during the next few hours,
    storms should gradually increase in coverage/intensity before
    spreading eastward along an evolving cold front.=20

    Around 40-50 kt of midlevel south-southwesterly flow (sampled by
    regional VWP) generally parallel to the frontal zone and the
    strengthening DCVA suggest an organized line of storms/QLCS should
    be the favored mode. While nocturnally cooling surface temperatures
    and lingering warm air aloft (per regional 00Z observed soundings)
    cast uncertainty on storms rooting at the surface (especially in the near-term), moist low-level southeasterlies beneath a developing
    30-35 kt low-level jet (and related warm-air advection) could
    eventually offset this given the strengthening midlevel height
    falls. Damaging gusts, aided by convective momentum transfer and an
    organizing cold pool, will be the main concern, though expanding
    low-level hodographs could also support embedded rotating updrafts
    and a non-zero risk for a brief tornado or two. While there is
    lingering uncertainty regarding surface-based storms (and related
    hazards), trends will be monitored for a possible watch issuance
    during the next few hours.

    ..Weinman/Guyer.. 08/18/2023

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!7Uo88t4zRjx45e4c66NoyvrnvRkXeU-pKls3Cbj9kyr5WGmZ9ELdFoQi-1siaWjDDxtDMbxGi= YSb_VR2ZZgjX0qvUrQ$ for graphic product...

    ATTN...WFO...ALY...PHI...BGM...CTP...

    LAT...LON 40837732 41237699 41727664 42047642 42277624 42547606
    42887588 42967557 42817500 42607459 42187450 41647475
    40247566 39927627 39827696 39997763 40197769 40477760
    40837732=20


    =3D =3D =3D
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