• MESO: Mesoscale Discussion 0394

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Monday, April 04, 2022 19:17:42
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    ACUS11 KWNS 041917
    SWOMCD
    SPC MCD 041916=20
    TXZ000-OKZ000-042145-

    Mesoscale Discussion 0394
    NWS Storm Prediction Center Norman OK
    0216 PM CDT Mon Apr 04 2022

    Areas affected...Portions of north-central/northwest TX and far
    southern OK

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

    Valid 041916Z - 042145Z

    Probability of Watch Issuance...80 percent

    SUMMARY...The threat for large to very large hail, damaging winds,
    and perhaps a tornado or two will increase this afternoon and
    evening. Watch issuance is likely.

    DISCUSSION...19Z surface observations show a nearly stationary front
    across parts of northwest TX into far south-central OK. The warm
    sector along and south/east of this boundary continues to
    destabilize this afternoon, with surface temperatures reaching into
    the 70s and low 80s, and dewpoints ranging from the mid 50s to low
    60s. Steep mid-level lapse rates around 7-8 C/km have overspread
    this region, and they are contributing to upwards of 1000 J/kg of
    MLCAPE as of 19Z. Additional diurnal heating and gradually cooling
    mid-level temperatures as an upper trough ejects over the southern
    Plains should allow MLCAPE up to 1500-2000 J/kg to develop across
    parts of northwest/north-central TX over the next few hours.

    Recent visible satellite imagery shows gradually deepening
    thunderstorms along and just behind the front in northwest TX, along
    with mid-level convection farther east over the open warm sector. As substantial convective inhibition continues to erode (see 18Z FWD
    sounding), and modest large-scale ascent overspreads the warm sector
    this afternoon, additional thunderstorms are expected to form along
    the front. Deep-layer shear of 35-50 kt will likely support
    supercells with this initial activity. Isolated large hail should be
    the main threat with this convection through the early evening,
    although some damaging winds could occur as well. Given the presence
    of steep mid-level lapse rates, some very large (2+ inches) hail
    appears possible.

    With time this evening, thunderstorms will likely grow upscale into
    a bowing cluster across north-central TX and far south-central OK as
    weak low-level southerly flow gradually increases. Damaging winds
    will become increasingly probable as this mode transition occurs.
    The tornado threat through the rest of the afternoon should remain
    fairly marginal given modest low-level shear (see recent VWPs from
    KDYX/KFWS). Still, a threat for a tornado or two may gradually
    increase this evening, mainly after 01Z, as low-level shear slowly
    strengthens. Regardless, the overall severe threat along/south of
    the front this afternoon will likely warrant watch issuance in the
    next couple of hours.

    ..Gleason/Mosier.. 04/04/2022

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!sI16jWOTg-K9xcZ8iOmRTC7-dVyEIgIMwFxuvouDsls_v9Rl44eaLL3aEYQFp4ZJ8lrQdzCV$=
    for graphic product...

    ATTN...WFO...FWD...OUN...SJT...

    LAT...LON 31589970 32159991 33029988 33739956 34209908 34409842
    34429774 34349692 33839687 33339718 32139816 31499876
    31359924 31589970=20



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  • From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Friday, March 31, 2023 17:51:57
    ACUS11 KWNS 311751
    SWOMCD
    SPC MCD 311751=20
    IAZ000-MOZ000-311915-

    Mesoscale Discussion 0394
    NWS Storm Prediction Center Norman OK
    1251 PM CDT Fri Mar 31 2023

    Areas affected...far northern MO...southern IA

    Concerning...Tornado Watch 93...

    Valid 311751Z - 311915Z

    The severe weather threat for Tornado Watch 93 continues.

    SUMMARY...Tornado potential will likely increase through 200-230pm
    CDT. Large to very large hail (2-3 inches diameter) is possible
    with the more intense supercells.

    DISCUSSION...Radar mosaic shows explosive supercell development
    across northern MO into southern IA. Surface temperatures have
    warmed into the low-mid 70s with surface dewpoints in the 60-62 deg
    F range. The latest RAP forecast soundings show very steep surface
    to 300-mb lapse rates (7.5 deg C/km) with impressive southwesterly
    speed shear with height. As the supercells mature and the surface
    low deepens through mid afternoon, some backing of near-surface
    winds is expected with low-level hodographs enlarging through 2-3pm.
    As this hodograph change occurs, tornado potential will markedly
    increase. Very large low-level buoyancy (0-3 km MLCAPE 200-300
    J/kg) and the intensifying low-level mesocyclones will combine to
    support the potential for strong tornadoes with supercells as they
    rapidly move northeast into south-central IA and approach the I-80
    corridor.

    ..Smith.. 03/31/2023

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!40sAsVIiQx9r4AyqRnzpLlt6js9abndHPTsWZxisWWZmP0FELSeqd9qjcpBQVGZEhM8CVQmZF= QL0rPEp6LMTroRHteY$ for graphic product...

    ATTN...WFO...DVN...DMX...EAX...

    LAT...LON 40659436 41639353 41719298 41559246 41289236 40339316
    40159376 40299427 40659436=20


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