472
AWUS01 KWNH 310202
FFGMPD
TNZ000-KYZ000-INZ000-ILZ000-MSZ000-MOZ000-ARZ000-310600-

Mesoscale Precipitation Discussion 0010
NWS Weather Prediction Center College Park MD
901 PM EST Thu Jan 30 2025

Areas affected...Portions of Kentucky and Tennessee

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

Valid 310200Z - 310600Z

SUMMARY...Areas of moderate to heavy rain will maintain a flash
flood threat across portions of the lower and middle OH Valleys
and much of KY through at least 06Z. Hourly rainfall of 0.5 to 1.0
inches will be possible along with 3 hourly rainfall up to 2
inches.

DISCUSSION...A broad area of moderate to heavy rainfall extended
along and east of the Mississippi River into the Ohio and
Tennessee Valley as of 0145Z. This area of rainfall has been
translating northeastward during the afternoon and early evening
and has been responsible for peak hourly rainfall up to about 0.75
inch in eastern AR/MO border into western KY.  MUCAPE has largely
remained below 500 J/kg but that was enough to support  3-hour
rainfall totals of 1.5 to 3 inches earlier.

The heaviest rainfall has been occurring at the nose of a 50-60 kt
low level jet measured between 925-850 mb, which has been
overrunning a surface warm front lifting north across northeast
Arkansas and far southern Tennessee at 00Z.  The axis of greatest
low level moisture transport is likely to continue to slowly shift
east into KY/TN through late evening with an elevated convergence
axis aloft focusing activity into the western lower OH Valley. The
orientation of this low level convergence axis will be parallel to
the mean steering flow, allowing for repeating rounds of moderate
to heavy rain.

While instability is likely to remain limited into the late
evening/early overnight hours, forcing will remain strong in the
form of low level warm air advection and convergence beneath a
strengthening area of upper level divergence located within the
right-entrance region of a 135-150 kt upper level jet max centered
over OH/PA/NY from 00Z soundings. Peak hourly rainfall of 0.5 to
1.0 inches and 3-hourly rainfall of 1-2 inches may result in
additional flash flood concerns across downstream locations along
the OH Valley...with the greatest concern for excessive rainfall
at locations where these rains fall on top of locations that have
already picked up 2 to 3+ inches of rain since this morning.
Embedded within this threat could be an isolated spot or two with
higher end runoff/flooding depending on local hydrologic
conditions.

Bann

...Please see www.wpc.ncep.noaa.gov for graphic product...

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

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

LAT...LON   38658585 38458319 37408284 36798460 35488777
            34838867 34818982 35518999 37188904 38108772