• Flood Potential Multiarea

    From Mike Powell@618:250/1 to All on Sat Jun 28 10:41:00 2025
    AWUS01 KWNH 281317
    FFGMPD
    TNZ000-KYZ000-INZ000-ILZ000-MOZ000-ARZ000-281900-

    Mesoscale Precipitation Discussion 0538
    NWS Weather Prediction Center College Park MD
    917 AM EDT Sat Jun 28 2025

    Areas affected...Southeast MO...Northeast AR...Western
    TN...Western KY...Southern IL...Southern IND...

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

    Valid 281315Z - 281900Z

    SUMMARY...Highly efficient pulse convection with sub-hourly 2"
    totals and eventual broader downdrafts/cell mergers that pose an
    isolated total to 3" and localized possible flash flooding.

    DISCUSSION...Regional RADAR and GOES-E conventional imagery loops
    depict developing convective clusters across the central MS Valley
    into the Lower Ohio River Valley. WV loop and RAP analysis shows
    sharp upper-level ridge and rapid directional/divergent flow aloft
    to support weak but multi-directional outflow to support stronger ascent/updraft strength. At the lower levels, solid 15-20kt
    solidly confluent 850mb flow through the Lower Ohio Valley
    supports convergence of very deep moisture/narrow skinny profiles
    with modest but sufficient instability (1000 J/kg of CAPE). Total
    PWats over 2" and vertical flux convergence will allow for highly
    efficient warm cloud processes (12-13Kft depth); but with weak
    shearing/tilting of updrafts, downdrafts should collapse downward
    likely resulting in focused totals up to 2" in less than 30-60
    minutes. Further rounds of thunderstorms will be generated along
    outflow boundaries; so with each cycle the potential for broader
    updrafts increases with some potential for mergers or expansion
    over areas that were hit with prior rounds suggesting an isolated
    spot of 3" is possible.

    Hydrologically, the area has been above normal in rainfall and
    soil saturation in most locations in the MPD area. FFG values of
    2"/hr seem reasonable and may be exceeded, suggesting widely
    scattered incidents of localized flash flooding is possible.

    Gallina

    ATTN...WFO...ILX...IND...LMK...LSX...LZK...MEG...PAH...SGF...

    ATTN...RFC...KRF...MSR...ORN...TIR...NWC...

    LAT...LON 39358687 39208590 38388561 37658621 36748804
    35128929 35289193 37299188 38048995 38768825

    = = =

    AWUS01 KWNH 281418
    FFGMPD
    MOZ000-ARZ000-OKZ000-KSZ000-281915-

    Mesoscale Precipitation Discussion 0539
    NWS Weather Prediction Center College Park MD
    1018 AM EDT Sat Jun 28 2025

    Areas affected...Northeast OK...Southwest MO...Northwest AR...
    Exteme Southeast KS...

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

    Valid 281415Z - 281915Z

    SUMMARY...Small slowly decaying MCC giving way to new slow
    moving/efficient thunderstorms along unstable edges.

    DISCUSSION...GOES-E 10.3um IR and regional RADAR mosaic depict a
    smaller than average MCC with well defined MCV crossing out of SE
    KS with the outer banding feature continuing to maintain on
    stronger than forecast southwesterly warm air advection. AMV/RAP
    analysis suggests a 300mb 50+kt jet speed max crossing out of
    central KS northeastward, exposing favorable right entrance ascent
    and favorable outflow to maintain and due to internal convection,
    slightly enhance the MCV. This has also aided a solid south to
    southwest 30kt inflow which has been orthogonal to the trailing
    banding feature resulting in continued development. Initial
    clusters near Tulsa have kicked some outflow southwestward and
    visible imagery shows bubbling Tcu along the upwind instability
    axis where MUCAPE values remain about 1500-2000 J/kg but are only
    uncapped in the vicinity of the isentropic ascent.

    Downstream, weak low level stratus appears to be burning off and
    increased insolation is helping to bolster surface to boundary
    layer heating across the high low level moisture environment
    between the small MCC and the thunderstorm activity spurred by
    downstream confluence in the MS/OH River Valleys. CIRA LPW layers
    show area of concern remains the core of nearly all layers of
    moisture with overall totals exceeding 2" and with deep layer warm
    cloud processes (13-14Kft), will support efficient rainfall
    production (especially where WAA/isentropic ascent is greatest)
    with 2-2.5"/hr possible.

    Slow deep layer flow given the MCC ciruclation is slowly to the
    east and crossing into recently saturated (higher relative soil
    moisture ratios into the mid to upper 60%) across the Ozark
    Plateau. Combined with naturally lower FFG values due to the
    complex terrain and low water crossings, the potential for
    exceedance of FFG is higher and with spots of 3-4" totals suggest
    it possible for scattered incidents of flash flooding to occur.

    Gallina

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

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

    LAT...LON 37999355 37789289 37439209 36719204 35639212
    35109266 35119365 35299443 35429552 35789639
    36679662 37109592 37329565 37529532 37759484

    $$
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