• MESO: Mesoscale Discussion 2015

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Tue Dec 13 19:33:41 2022
    ACUS11 KWNS 131933
    SWOMCD
    SPC MCD 131933=20
    ARZ000-LAZ000-TXZ000-132130-

    Mesoscale Discussion 2015
    NWS Storm Prediction Center Norman OK
    0133 PM CST Tue Dec 13 2022

    Areas affected...East/Southeast TX...Northwest LA...Southern AR

    Concerning...Tornado Watch 582...

    Valid 131933Z - 132130Z

    The severe weather threat for Tornado Watch 582 continues.

    SUMMARY...Threat for supercells capable of all severe hazards
    continues across Tornado Watch 582. A downstream Tornado Watch will
    likely be needed across southern AR, northwest LA, and
    east/southeast TX.

    DISCUSSION...Recent surface analysis places a triple point low about
    20 miles east of PRX, with a cold front extending southwestward from
    this low through central TX. A warm front also extends southeastward
    from this low through northwest and central LA (delineated well by
    the 65 deg F isodrosotherm). Thunderstorm activity along the cold
    front has weakened over the last hour or so, while showers have
    increased throughout the warm sector. Most of these warm sector
    showers have not strengthened significantly. However, very recent
    trends have signaled some strengthening with the storms in Anderson,
    Houston, and Robertson Counties, evidenced by increasing
    reflectivity and lightning activity. Given their placement in the
    warm sector, some additional strengthen/maturing into supercells is
    possible.

    The warm front is expected to continue slowly lifting northward
    while the cold front advances eastward. This will take the warm
    sector farther east into more of east/southeast TX, northwest LA,
    and southern AR through this evening. As such an additional Tornado
    Watch will be needed for portions of the region within the next hour
    or so. Given the favorable parameter space, PDS wording is being
    considered.

    ..Mosier/Hart.. 12/13/2022

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!_sLxSou07UlZKqT4HnTzLS0rBB_19q1A75qbKsYXygaXGfKa4RGDhVqKdg-QRnEqEtSWPyyRz= LR0QGzQFpEI_4tzvNQ$ for graphic product...

    ATTN...WFO...LZK...LCH...SHV...HGX...FWD...

    LAT...LON 30739640 31859603 33499430 33859288 33259214 30999352
    30249529 30739640=20


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  • From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Fri Aug 18 22:38:55 2023
    ACUS11 KWNS 182238
    SWOMCD
    SPC MCD 182238=20
    AZZ000-190115-

    Mesoscale Discussion 2015
    NWS Storm Prediction Center Norman OK
    0538 PM CDT Fri Aug 18 2023

    Areas affected...Parts of south-central Arizona

    Concerning...Severe potential...Watch unlikely=20

    Valid 182238Z - 190115Z

    Probability of Watch Issuance...5 percent

    SUMMARY...Sporadic strong to severe gusts could accompany any
    stronger thunderstorms that develop into the evening. A watch is not
    expected.

    DISCUSSION...Widely scattered high-based thunderstorms are evolving
    westward over parts of southeastern AZ this afternoon, with some
    recent evidence of locally congealing cold pools. Additional
    thunderstorms are spreading northward across the International
    border in southwestern AZ. Subtle backing of 15-20 kt midlevel flow
    (per regional VWP data) will allow this activity to continue spreading/developing west-northwestward through the afternoon across
    parts of south-central AZ. The pre-convective environment is
    characterized by a hot/deeply mixed boundary layer (and related
    steep low-level lapse rates) beneath a plume of rich midlevel
    moisture (PW near 1.6 inches per GOES-16 and the latest PHX ACARS
    soundings). While modest deep-layer shear (around 20-kt 0-6 km shear
    per VWP data) will generally limit updraft longevity and
    organization, the deep inverted-V thermodynamic profile will support
    strong to locally severe gusts with the stronger storms that develop
    into the evening -- especially with any localized clusters that
    evolve. Overall, the severe threat appears too sporadic for a watch.

    ..Weinman/Bunting.. 08/18/2023

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!-EOooIMtPHB2tnaMrZo4swHFA1pV8SC9uju5McXiA0KFZTrCZ3vS_ZTGso_tRfjaD1rDuGKGt= nvolXxMZbo3QaV7bAI$ for graphic product...

    ATTN...WFO...TWC...FGZ...PSR...

    LAT...LON 31621015 31291031 31271115 31631226 31951334 32271336
    32751315 33451272 33871239 34061199 33971114 33581041
    32411003 31621015=20


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