Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Thu Aug 08 2024 21:44:46

AWUS01 KWNH 082144
FFGMPD
OHZ000-090330-

Mesoscale Precipitation Discussion 0840
NWS Weather Prediction Center College Park MD
544 PM EDT Thu Aug 08 2024

Areas affected...Northeast to Central Ohio...

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

Valid 082145Z - 090330Z

SUMMARY...Very slow/Stationary cells with capability of 1.75"/hr
rates with 2-3" focused totals inducing a few incidents of flash
flooding into the early overnight.

DISCUSSION...An atypical environmental setup exists across Ohio
with the potential for scattered thunderstorms to initiate over
the next few hours.  A old surface boundary is analyzed from east
of Cleveland toward a weak surface wave near Zanesville before
dropping into northeast KY.  CIRA LPW denotes a narrow band of
enhanced moisture in the Sfc-850mb layer with values of .75-.8"
and with weak convergence through that depth as well with
northwesterly flow across much of the Tilled Plains intersecting
with weak downsloping flow/influence from Tropical Cyclone Debby.
Aloft, a downstream strong confluence zone into the polar jet and
return anticyclonic outflow from Debby across NY provides solid
divergence aloft to support broad scale ascent.  Filtered
insolation through cirrus has heated the low levels to the mid to
upper 80s supporting a band of 1000-1500 J/kg of MLCAPE generally
coincident with the moisture/convergence.=20

GOES-Visible and RADAR note a few of the congested Cu are starting
to build into deeper cores across the area of concern.  Given the
parameters in place, solid flux convergence should support rates
of 1.75"/hr.  Deep layer steering is in a col between the cyclone
to the southeast and the Deeper closed low over the upper Great
Lakes, generally about 0-5kts.  Inflow and outflow appear to be
less obstructed than a normal very slow moving updraft to allow
for increased duration/updraft cycles to allow for 1-2 hours of
longevity before producing weak outflow.  This outflow is probable
to induce newer development on the periphery and eventually
colliding outflows may support broader updraft/slab ascent for
broader downdrafts and rates up to 2".  A such, 2-3" focus totals
result in possibility of inducing localized flash flooding
conditions.  This is more likely across northeast Ohio where FFG
values are naturally a tad lower and there is increased potential
for intersecting hydrophobic urban conditions resulting in
increased run-off.=20=20=20

Gallina

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!6_wfu9BRy0cyZZYIvk7vovjVLK6Yk8gvOmUgJIEilWvvKiuawKYFMvjJigMUCuk1rBYq=
cgThD7v2ca5XYgprPs6qidI$  for graphic product...

ATTN...WFO...CLE...ILN...PBZ...RLX...

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

LAT...LON   41898100 41608086 40758132 39798197 39388257=20
            39438312 39848325 40508299 41448216 41538207=20
            41678164=20

=3D =3D =3D
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