• Heavy Rain/Flood SC/NC/VA

    From Dumas Walker@21:1/175 to All on Fri Aug 9 12:49:00 2024
    AWUS01 KWNH 091539
    FFGMPD
    VAZ000-NCZ000-SCZ000-092135-

    Mesoscale Precipitation Discussion 0849
    NWS Weather Prediction Center College Park MD
    1138 AM EDT Fri Aug 09 2024

    Areas affected...eastern SC/NC border into eastern NC and far
    southeastern VA

    Concerning...Heavy rainfall...Flash flooding likely

    Valid 091535Z - 092135Z

    SUMMARY...Training of heavy rain from SSW to NNE is expected to
    generate renewed flash flood concerns through mid-afternoon for
    eastern NC, potentially extending northward into southeastern VA.
    While the coverage of higher intensity rain may be limited,
    rainfall rates between 1-3 in/hr are likely.

    DISCUSSION...Radar imagery over the past 1-2 hours has shown
    semi-organized lines of showers and thunderstorms located over
    eastern NC and just offshore, associated with confluent flow in
    the 925-850 mb layer. Winds in this layer have weakened compared
    to last night but remained southerly in the 20-30 kt range over
    the Outer Banks and Pamlico Sound, weakening and veering with
    western extent. Precipitable water values ranged between 2.2-2.4
    inches and MLCAPE was limited to the Coastal Plain, as high as
    1500 J/kg along the coast, but lower to the west.

    Although Post-T.C. Debby is forecast to quickly track northward
    today from western PA, the flow regime across eastern NC will
    remain similar well into the afternoon per recent RAP forecasts.
    This will favor the occasional generation of a narrow axis or two
    of heavy rain with training, given a similar orientation of the
    low level confluence to the deeper layer steering flow. Cloud
    cover will likely maintain limited CAPE values for inland portions
    of eastern NC, which should focus shower/thunderstorm activity
    over the eastern 1/4 of NC, perhaps extending northward into
    southeastern VA.

    Given recent rainfall over the past 2-3 days over the region, as
    high as 10+ inches over the southern coast of NC, soils are fairly
    saturated and have limited infiltration capacity. Training bands
    with 1-3 in/hr rainfall rates are expected through the afternoon
    which would likely result in renewed areas of flash flooding.
    Precise location of these bands is uncertain, but a good portion
    of eastern NC into southeastern VA will remain in a favorable
    setup for these narrow bands of training well into the afternoon.

    Otto

    ATTN...WFO...AKQ...ILM...MHX...RAH...

    ATTN...RFC...MARFC...SERFC...NWC...

    LAT...LON 37717595 37547532 36597547 35027540 33817703
    33647847 34147916 35347834
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