• MESO: Heavy Rain/Flood OK

    From Mike Powell@618:250/1 to All on Wed May 1 08:05:00 2024
    AWUS01 KWNH 011205
    FFGMPD
    OKZ000-011630-

    Mesoscale Precipitation Discussion 0203
    NWS Weather Prediction Center College Park MD
    804 AM EDT Wed May 01 2024

    Areas affected...Central to Eastern Oklahoma...

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

    Valid 011205Z - 011630Z

    SUMMARY...Increasing warm-advection T'storms capable of 1.5-3"
    over sensitive soils may pose increased runoff and spotty flash
    flooding incident(s) this morning.

    DISCUSSION...GOES-E 10.3um IR shows a well defined MCV from the
    decaying MCS over far southeastern OK into western AR. The MCS
    has laid out a well defined outflow boundary from the MCV
    along/just north of the Red River before angling back northwest
    from Love county toward Custer county, OK. VWP suite depicts a
    stronger than forecast lingering LLJ with FDR suggesting 50+ kts
    of south-southwesterly flow with slowly veering flow in the wake
    of the MCS across southern and eastern OK. CIRA LPW also notes an
    enhanced pocket of moisture in the 850-700mb layer nearing the Red
    River into SW OK which also matches up with MUCAPE axis of 2000
    J/kg along the western edge of that outflow. As such, a gradient
    of unstable mid-level air with solid isentropic ascent has sparked
    an NW to SE axis of thunderstorms. Moisture is modest in the
    1.25-1.4" range and flux is also supporting of up to 1.5"/hr rates
    with occasional localized convergence values that may supports
    spots up to 2".

    With a veered steering profile, initial cells are lifting
    northeastward, but propagation vectors and 500-300mb flow from the
    west suggests some eastward/southeastward motions may start to
    unfold over the next few hours along/near the outflow boundary.
    Given continued upwind ascent (per RADAR suite), redevelopment
    along the outflow as the boundary slowly drifts west, may allow
    for repeating/back-building even prior to the convergence in
    deeper-steering flow. This may allow for 1 to 2 hours of duration
    and allow for spots of 1.5-3" totals. The bad news, the
    placement/track of the southern axis across south-central OK will
    cross sensitive, recently flooded areas...where AHPS depicts a
    broad area of 250%+ of 7day rainfall anomalies from Cotton to S
    Osage county and southeastward, with spots of 500%+ from Love to Seminole/Hughes county. So currently, not ideally aligned, but
    still concerning enough to suggest spots/localized incidents of
    flash flooding are possible through this morning.

    Further north near the KS/OK border...Another similar axis has
    developed along an exposed area of return southeasterly flow not
    generally obstructed by ongoing convection to the south and
    southwest. The surface front is also sagged across this area
    while the main LLJ core lifts the warm front further west. So a
    bit of enhanced convergence across areas hit hard last night,
    bleeding into Osage county...may see a similar if slightly muted
    situation as described above with a spot of flash flooding still
    possible as well before diurnal convective minima/stabilization
    occurs later this morning.

    Gallina

    ATTN...WFO...OUN...TSA...

    ATTN...RFC...ABRFC...NWC...

    LAT...LON 36979725 36879643 36219563 35449513 34869507
    34119534 33889613 33879644 34029699 34509783
    35219842 35579833 36119761 36349758 36719748


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