AWUS01 KWNH 181100
FFGMPD
TNZ000-KYZ000-181600-

Mesoscale Precipitation Discussion 1182
NWS Weather Prediction Center College Park MD
600 AM EST Wed Dec 18 2024

Areas affected...Central Kentucky into Western Tennessee...

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

Valid 181100Z - 181600Z

SUMMARY...Progressive convective line with embedded intense
downdrafts capable of 1-1.5"/hr and quick 1.5-2.5" totals across
low FFG values suggest widely scattered incident or two of flash
flooding remain possible through late morning.

DISCUSSION...RADAR mosaic and GOES-E 10.3um EIR show a progressive
convective line with slight uptick of vigor over the last hour or
so as the deep layer moisture flux/convergence aligns with
remaining instability axis across central KY back to SW TN. Core
of highest theta-E air remains across W TN with 500-1000 J/kg of
CAPE that decreases slowly northeastward into central KY. GOES-E
WV suite shows polar upper-level trough has made main push east
and southward out of the Plains toward the MS Valley. Broad
divergence along the right entrance to the downstream jet streak
through the Great Lakes continues to maintain solid large scale
ascent while maintaining strength of the the LLJ across Arkansas
into the TN River Valley. Surface moisture in the mid-50s,
combined with the strong moisture flux convergence along the
leading edge of the convective line will continue to support
intense sub-hourly rain-rates in the range of 1.5-1.75"/hr though
duration is likely to limit totals to 1-2" with perhaps up to an
additional .5" within the broadening moderate precipitation shield.

The progressive nature should limit overall totals; however, the
line is moving into overall lower FFG values of 1-1.5"/hr and
1.5-2"/3hr which remain possible of being locally exceeded.
Overall coverage and magnitude of flash flooding is likely to be
limited on the low end of exceedance. However, the potential for
flash flooding will remain possible until about 15-18z when
instability is nearly fully exhausted and moving into a more
stable, lower temperature/moisture environment through the
Cumberland Plateau.

Gallina

ATTN...WFO...JKL...LMK...MEG...OHX...PAH...

ATTN...RFC...LMRFC...OHRFC...NWC...

LAT...LON 38218366 37728326 36728462 35918596 35478705
35168826 35198946 35638955 36428855 36958775
37918608 38188508

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