• MESO: Mesoscale Discussion 0484

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Mon May 3 04:45:56 2021
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    ACUS11 KWNS 030445
    SWOMCD
    SPC MCD 030445=20
    ALZ000-MSZ000-030645-

    Mesoscale Discussion 0484
    NWS Storm Prediction Center Norman OK
    1145 PM CDT Sun May 02 2021

    Areas affected...Portions of northern MS into northwestern AL

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

    Valid 030445Z - 030645Z

    Probability of Watch Issuance...40 percent

    SUMMARY...An isolated tornado threat may persist overnight. Watch
    issuance is possible, but will depend on signs on increasing storm
    intensity.

    DISCUSSION...A long-lived, low-topped supercell that produced a
    tornado earlier in Tupelo MS has weakened somewhat as it has moved northeastward into northwestern AL and encountered a less unstable
    airmass, but it is still showing signs of occasional low-level
    rotation. Additional low-topped convection has formed in the past
    hour across parts of northern MS in a continued strong low-level
    warm advection regime. A low-amplitude shortwave trough is moving
    over the Mid-South now per recent water vapor satellite imagery.
    Ascent associated with this upper trough and the low-level warm
    advection will probably continue to support convection across
    northern MS and parts of northwestern AL through the early overnight
    hours. Deep-layer shear remains adequate for storm organization.
    Recent VWPs from KGWX show some veering of the 0-1 km flow in the
    past hour or so, and this trend should continue as the core of the
    low-level jet shifts eastward into AL/TN overnight. Still, low-level
    shear is expected to remain more than adequate for updraft rotation,
    with effective SRH around 200-300 m2/s2 likely to remain in place
    over this region for at least several more hours. Isolated tornadoes
    may occur if any of this ongoing low-topped convection can
    strengthen further. However, this potential appears uncertain given
    the weak instability in place and the stabilizing effects of earlier
    storms. Tornado Watch issuance is possible in the next couple of
    hours, but will largely be dependent on radar and observational
    trends.

    ..Gleason/Thompson.. 05/03/2021

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!pPUhzhPdqNcc-nD4hOgc01z5Cx2m4cF2gekdTS49jxt75O6My3C6fN1NMasAyiN3TpN1H7qY$=
    for graphic product...

    ATTN...WFO...BMX...HUN...MEG...JAN...

    LAT...LON 33599090 34389054 34958895 34948781 34718762 33958774
    33708846 33329073 33599090=20



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