• Heavy Rain/Flooding MO/KS

    From Mike Powell@618:250/1 to All on Sat Jul 13 10:04:00 2024
    AWUS01 KWNH 131122
    FFGMPD
    MOZ000-KSZ000-131630-

    Mesoscale Precipitation Discussion 0614
    NWS Weather Prediction Center College Park MD
    722 AM EDT Sat Jul 13 2024

    Areas affected...Southern and Central Missouri, far eastern Kansas

    Concerning...Heavy rainfall...Flash flooding possible

    Valid 131121Z - 131630Z

    Summary...Rapid growth of thunderstorms associated with a
    shortwave will produce heavy rainfall rates of 1-2"/hr through
    late morning. Some slow movement of these cells could result in
    1-3" of rain with locally higher amounts. Flash flooding is
    possible.

    Discussion...The regional radar mosaic early this morning shows
    rapidly expanding thunderstorms from eastern Kansas into
    west-central Missouri. These thunderstorms are developing near the
    edge of a stationary front that is slowly lifting northward, and
    downstream of a shortwave noted on GOES-E WV imagery pivoting
    across eastern KS. Forcing across MO is being aided as well by a
    modest LLJ of 20-30 kts out of the SW, and a weak but diffluent
    RRQ of a modest jet streak dropping south into the Central Plains.
    The LLJ is also helping to draw higher PW air northward into the
    region, with the recent SPC RAP analysis indicating a bubble of
    1.5-1.75 inch PWs in the vicinity of the convection, which is
    overlapping favorable MUCAPE of around 2000 J/kg.

    The evolution this morning is challenging due to a lack of support
    from high-res CAMs, but at least the 06Z HRRR and the 06Z NAMNest
    have some indication of development, although both are either too
    weak or displaced. However, the 00Z RRFS members, including the
    operational p1 and experimental p2, p3, and p4 are initializing
    much better to current radar, and suggest continued upscale growth
    of this activity through late morning. The ingredients support
    this evolution until the LLJ veers and weakens after around 16Z,
    so the RRFS is used heavily for this MPD. The anomalous PWs and
    warm cloud depths will continue to support efficient warm-rain
    processes, and rainfall rates have a 30-50% chance of exceeding
    1"/hr, with short-duration 2+"/hr rates also possible. Corfidi
    vectors angled strongly to the right of the mean flow suggest
    backbuilding of convection will occur ahead of the shortwave, and
    this will lower net storm motions to just around 10 kts resulting
    in 1-3" of rainfall with locally higher amounts in some areas.

    Although confidence in evolution is modest, the favorable
    ingredients, RRFS support, and FFG that is compromised in some
    areas to just 1.5"/3hrs from recent rainfall suggests at least
    isolated instances of flash flooding are possible during the next
    several hours.


    Weiss


    ATTN...WFO...EAX...ICT...LSX...SGF...TOP...TSA...

    ATTN...RFC...ABRFC...LMRFC...MBRFC...NCRFC...NWC...

    LAT...LON 39179311 39169243 38929127 38459062 37759050
    37279091 36799233 36739291 36839404 37079489
    37359553 37589559 37919545 38389510 39039415
    39119381
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