Subj : Flood Threat So KY/NE TN
To   : All
From : Mike Powell
Date : Sun Jun 28 2026 09:49:10

AWUS01 KWNH 281402
FFGMPD
VAZ000-NCZ000-TNZ000-KYZ000-281900-

Mesoscale Precipitation Discussion 0545
NWS Weather Prediction Center College Park MD
1000 AM EDT Sun Jun 28 2026

Areas affected...Southern KY...Northeast TN

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

Valid 281400Z - 281900Z

SUMMARY...Heavy showers and thunderstorms are expected to continue
to locally backbuild and train over the same area for a few more
hours. Portions of mainly southern KY and into northeast TN are
likely to see more areas of flash flooding which may be locally
significant going through the early to mid-afternoon hours.

DISCUSSION...The mid-morning GOES-E IR satellite imagery shows a
long-lived northwest/southeast axis of cold-topped convection
continuing to drop down across areas of southern KY through
northeast TN. This axis of convection has been locally
backbuilding and training over the same areas for several hours,
and it continues to feature pockets of extremely heavy rainfall
rates which have occasionally reached 2 to 3 inches/hour.

The latest RAP data shows the convection traversing a well-defined
instability gradient which is aligned with a surface
trough/outflow boundary. MLCAPE values across western KY and
adjacent areas of western and central TN are on the order of 1500
to 2000 J/kg which is bumping up against the convectively
reinforced cold pool across southern KY through northeast TN.
Westerly low-level flow at 850mb continues to be on the order of
20 to 30 kts which is favoring an isentropic
ascent/frontogenetical forcing component to the convective threat,
and especially with the modest, but persistent moisture and
instability transport.

Given the setup, and with PWs of as much as 2.0 to 2.25 inches,
the rainfall rates will likely continue to be quite extreme with
the stronger convective cores and capable of reaching 2 to 3
inches/hour. The good news though is that the cloud top
temperatures do appear to be leveling off just a bit, and with
some slackening of the westerly low-level flow, the ongoing
convection should begin to gradually weaken fairly soon.

Regardless, some localized additional rainfall totals may reach 3
to 4+ inches through mid-afternoon. This will support more areas
of flash flooding, some of which may be significant, given the
ongoing considerable runoff problems, sensitive soil conditions,
and terrain-driven considerations.

Orrison

ATTN...WFO...GSP...JKL...LMK...MRX...OHX...

ATTN...RFC...ORN...TIR...NWC...

LAT...LON   37508521 37248416 36488320 35868294 35498352=20
            35558434 36028510 36728582 37268590=20

$$
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