Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Tue Jun 17 2025 18:34:42

AWUS01 KWNH 171833
FFGMPD
WVZ000-OHZ000-TNZ000-KYZ000-INZ000-ALZ000-MSZ000-180032-

Mesoscale Precipitation Discussion 0469
NWS Weather Prediction Center College Park MD
233 PM EDT Tue Jun 17 2025

Areas affected...OH Valley...TN Valley

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

Valid 171832Z - 180032Z

Summary...Repeating rounds of showers and thunderstorms with
2-2.5"/hr max rainfall rates are expected to produce isolated to
scattered instances of flash flooding.

Discussion...Regional radar mosaic highlights a corridor of
expanding showers and thunderstorms along and ahead of a broad
upper-trough and embedded vort-max located in the TN Valley.
Downstream of this feature, a NE-SW oriented confluence axis was
analyzed in the 925-850 hPa layer, which cells are generally
organizing along.

Very moist and unstable inflow characterized by 2-2.1" PWATs,
eventually 1000-1500 J/kg MLCAPE (in a "tall-skinny" profile), and
warm cloud depths of 13,000-14,000 feet should foster very
efficient warm rain processes with 2-2.5"/hr max rainfall rates --
although sub-hourly rates could be even higher on the storm scale
with cell mergers.=20

As storms expand in coverage this afternoon, the parallel
orientation of the forcing to the steering flow should favor
repeating and merging of cells, prompting isolated to scattered
flash flooding across the area. Both the 12z HREF and REFS
neighborhood probabilities highlight a moderately-high likelihood
(35-50%) of 1-3 HR FFG exceedance as this activity matures through
0z, with the centroid generally located over East-Central KY.
However, even outside of this area, saturated soils per NASA SPoRT
and reduced FFGs (.75-2"/hr) suggest isolated to scattered flash
flooding is likely with scattered rainfall of 2-3" expected across
the area.

Asherman

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!4S0bhzzfycvCRr0UZjzQdZXOG2f9LbiaohCD2fdO05_DdC0KaJUJm4FWOwbn9TYxsPhF=
MCg766BlaZyWaIKRqaKowNs$  for graphic product...

ATTN...WFO...HUN...ILN...IND...JKL...LMK...MEG...MRX...OHX...
PAH...PBZ...RLX...

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

LAT...LON   40058326 39968210 39178139 38138152 37388241=20
            36808360 35938497 35128554 34578627 34478786=20
            35168888 36178899 38068702 39378505=20

=3D =3D =3D
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