• Flood Threat NE/IA/MO

    From Mike Powell@618:250/10 to All on Thu Jun 11 08:14:10 2026
    AWUS01 KWNH 110905
    FFGMPD
    MOZ000-IAZ000-NEZ000-111504-

    Mesoscale Precipitation Discussion 0383
    NWS Weather Prediction Center College Park MD
    504 AM EDT Thu Jun 11 2026

    Areas affected...portions of southern/southeastern Nebraska into
    southern Iowa and far northern Missouri

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

    Valid 110904Z - 111504Z

    Summary...Scattered thunderstorms will produce heavy rainfall,
    with pronounced local training expected to continue. Flash
    flooding is possible.

    Discussion....Recent radar mosaic imagery depicts an east-west
    oriented band of deep convection extending along I-80 from near
    Lexington to near Lincoln. The storms have formed on the nose of
    a strong southerly low-level jet, which has increased to around 55
    knots over the past couple hours over much of Kansas.
    Additionally, the storms are focused along a moist axis, with PW
    values extending from near 1.25-1.75 along I-80 (highest with
    eastward extent. Steep mid-level lapse rates aloft (around 8C/km)
    were supporting robust, intense updrafts, while pronounced
    training was also noted due to storm motions parallel to the axis
    of initiation. This has fostered development of 1+ inch/hr rain
    rates in several spots per MRMS.

    The ongoing scenario supporting flash flooding should continue for
    several hours while translating quickly eastward into southern
    Iowa through 12-14Z (7-9am central). Storm motions are relatively
    fast (around 40-45 knots), but pronounced training should enable
    development of 1.5 inch/hr rain rates to continue at times along
    the convective band as long as storms don't grow upscale into
    bowing/linear segments too aggressively. FFG thresholds are
    around 1.5 inch/hr areawide, but drop some to around 1 inch/hr in southwestern/southern Iowa (locally lower) where copious amounts
    of antecedent rainfall have been observed recently and soils are
    wet. At least isolated instances of flash flooding are expected
    as this convective band continues to evolve through 15Z/10a central.

    Cook

    ATTN...WFO...DMX...DVN...EAX...GID...LBF...OAX...

    ATTN...RFC...KRF...MSR...NWC...

    LAT...LON 42119658 42089443 41909298 41419216 40789201
    40439287 40119614 40169978 41269982 41629906

    $$
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