• MESO: Mesoscale Discussion 1121

    From COD Weather Processor@1:2320/107 to wx-storm@lists.illinois.edu on Sat Jun 13 17:40:50 2026
    ACUS11 KWNS 131740
    SWOMCD
    SPC MCD 131740=20
    KYZ000-ILZ000-TNZ000-MOZ000-ARZ000-131915-

    Mesoscale Discussion 1121
    NWS Storm Prediction Center Norman OK
    1240 PM CDT Sat Jun 13 2026

    Areas affected...portions of the mid-Mississippi and lower Ohio
    Valleys

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

    Valid 131740Z - 131915Z

    Probability of Watch Issuance...40 percent

    SUMMARY...An ongoing convective cluster in southern Missouri has
    exhibited some intensification over the past hour, with isolated
    damaging wind gusts and large hail possible.

    DISCUSSION...Latest GOES imagery and lightning data indicate that an
    ongoing convective cluster in southern Missouri downstream of an MCV
    over southeast Kansas has intensified some, with an uptick in
    lightning and modest cloud top cooling noted over the past hour.
    While denser cloud cover is present downstream of this cluster
    across much of southeastern Missouri, clear conditions farther south
    in northeast Arkansas and low-level warm, moist air advection are
    contributing to a destabilizing air mass with minimal remaining
    inhibition indicated by latest objective analysis and RAP forecast
    soundings.

    Latest high-res guidance continues to poorly capture this complex.
    Thus, the exact evolution remains uncertain. However, guidance does
    suggest that sufficient effective shear (25-30+ kts) will remain in
    place owing, in part, to the presence of the upstream MCV (and
    perhaps a second, weaker MCV over southern Missouri). Coupled with
    the moderately unstable environment, it is possible that this
    complex continues east-southeastward over the next couple of hours.
    In this scenario, a greater threat for damaging wind gusts (and
    perhaps an instance or two of large hail) may develop through the
    afternoon should this cluster intensify. Trends are being monitored,
    and a Severe Thunderstorm Watch may be needed pending further intensification/persistence of this cluster.

    ..Chalmers/Mosier.. 06/13/2026

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!7u7wC4a8qj3Fx1vvWyQH8dffK-73H83RIYLkrkxiACcoNRhWMQXtoLxb-QbONllAasxtaXc4A= a6ZPHnMjI5LjszvxQc$ for graphic product...

    ATTN...WFO...PAH...MEG...LSX...LZK...SGF...

    LAT...LON 37339130 37509096 37599042 37638986 37628952 37548922
    37378899 37058872 36788864 36438866 36108891 35848933
    35768969 35769008 35799057 35889100 36039147 36179174
    36469199 36649199 36879188 36979178 37179155 37339130=20

    MOST PROBABLE PEAK WIND GUST...55-70 MPH
    MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN


    =3D =3D =3D
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    * Origin: Capitol City Online (1:2320/107)