Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Thu Sep 28 2023 09:57:28

AWUS01 KWNH 280957
FFGMPD
TNZ000-KYZ000-ILZ000-281555-

Mesoscale Precipitation Discussion 1109
NWS Weather Prediction Center College Park MD
556 AM EDT Thu Sep 28 2023

Areas affected...Far Southern IL...Western/South-Central
KY...Northern TN

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

Valid 280955Z - 281555Z

SUMMARY...Some additional concerns for flash flooding will exist
through the morning hours from locally repeating/training rounds
of heavy showers and thunderstorms.

DISCUSSION...An upper-level trough and associated closed low
continues to impact areas of the Great Lakes and portions of the
OH Valley early this morning. Surface data shows a well-defined
frontal zone situated very close to the OH River, and shortwave
energy rounding the base of the upper trough has been facilitating
the advance of a wave of low pressure off to the east along the
front.

An axis of relatively stronger low-level convergence near and east
of the low center continues to work in tandem with as much as 500
to 1000 J/kg of MUCAPE for some broken bands of showers and
thunderstorms. Some of the stronger forcing aloft associated with
the vort energy and broader height falls continues to be a player
as well in seeing pockets of sustainable convection.

Dual-pol radar more recently has been tending to redevelop and
focus convection back across areas of far southern IL and into
western KY, and this is where there is the nose of greatest
instability and close proximity of an outflow boundary resulting
from the earlier convection overnight farther to the north.

The general expectation is that there will be a broken axis of
additional convection going through the morning hours that will
impact areas of western to south-central KY, and possibly sneaking
into areas of northern TN as shortwave energy continues to
traverse the OH Valley. Some of the 00Z/06Z HREF guidance suggests
potential for repeating/training convective cells across these
areas.

Rainfall rates will be capable of reaching 1.5+ inches/hour, and
locally an additional 2 to 4 inches of rain may be possible by mid
to late morning.

Some additional concerns for some flash flooding will exist this
morning as a result from these additional rounds of heavy showers
and thunderstorms.

Orrison

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!6b0X1MNgRkWqlQywGTqKNDC3-a3tF-ABvCveDeK3g9UEvTFRiUklnZAcyWJSEqu2bfnW=
fueEWGSO7a6Y9oGF7RF2up0$  for graphic product...

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

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

LAT...LON   37728792 37358690 37138559 36908471 36478432=20
            35968490 35798655 36158820 36838908 37348905=20
            37668863=20

=3D =3D =3D
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