• Flood Potential KSOKMOAR

    From Mike Powell@618:250/1 to All on Fri Jul 18 09:58:14 2025
    AWUS01 KWNH 180924
    FFGMPD
    MOZ000-ARZ000-OKZ000-KSZ000-181500-

    Mesoscale Precipitation Discussion 0742
    NWS Weather Prediction Center College Park MD
    523 AM EDT Fri Jul 18 2025

    Areas affected...Southern & Southeastern KS...Northeast
    OK...Soutwest MO...Far Northeast AR

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

    Valid 180925Z - 181500Z

    SUMMARY... Solid WAA isentropic ascent into increasingly veering
    steering flow may allow for 2"/hr rates training resulting in a
    few spots of localized flash flooding.

    DISCUSSION...09z surface map shows a surface wave just southwest
    of Enid, OK with the stationary front crossing through the OK/MO
    border where a weak meso-low could be analyzed from older
    convective complex over NE AR/NE OK in the early overnight hours.
    The older outflow has retrograded west past OWP and OKM steepening
    the isentropes across NE OK. VWP and RAP analysis depict
    southerly surface flow veering through 850mb before becoming
    westerly at 700mb; displaying over 90 degrees of WAA veering
    though winds are only 20-30kts at the core of the LLJ and
    convective initiation level around 850mb. MUCAPE above the level
    is over 2000 J/kg and surface to 500mb PW is near or slightly
    above 2" suggesting updrafts will be capable of efficient rainfall
    production over 2"/hr with broader cores. Given the front extends southeastward due to the outflow, a few cells may track closely to
    areas already affected by flash flooding from Delaware county, OK
    into NW AR; though best ascent/instability aloft is generally
    along and north of the OK/KS line.

    As noted, the 700mb flow is generally parallel to the development
    region but is also weaker/slower than near the surface; this will
    allow for some increased duration but also some subtle
    upwind/flanking development for some additional duration of heavy
    rainfall due to back-building/repeating cells. Given this
    repeating potential, spots of 2-4" are possible especially over SE
    KS, which coincidentally has the lower FFG values at 1-1.5"/hr and
    1.5-3"/3hrs. Limitation is going to be directly tied to the
    strength of the LLJ and moisture convergence through isentropic
    ascent. While, slow weakening is expected; hi-res CAMs are
    typically are too fast to weaken WAA/convection from LLJ ascent,
    but timing is likely to be within the 13-15z time period and so
    risk of flash flooding can extend into SW MO as well.

    Gallina

    ATTN...WFO...ICT...SGF...TSA...

    ATTN...RFC...KRF...ORN...TUA...NWC...

    LAT...LON 37959690 37889576 37619452 37179399 36629369
    36199406 36029469 36239552 37019648 37279791
    37789793

    $$
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