Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Sun Aug 13 2023 00:19:41

AWUS01 KWNH 130019
FFGMPD
PAZ000-MDZ000-WVZ000-OHZ000-130600-

Mesoscale Precipitation Discussion 0915
NWS Weather Prediction Center College Park MD
818 PM EDT Sat Aug 12 2023

Areas affected...Portions of southwestern PA...southeastern
OH...northern WV...far western MD

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

Valid 130015Z - 130600Z

Summary...Localized rainfall rates of 1-2"/hr will continue, with
additional short-term totals of 2-3" expected. Additional
scattered instances of flash flooding are considered likely.

Discussion...A line of semi-discrete strong to severe
thunderstorms continue to progress towards the east-southeast,
well ahead of a trailing cold front across central OH and Lake
Erie. These storms have had a history of producing 1-2"/hr
rainfall rates (along with scattered instances of flash flooding),
and the expectation is that these localized rates will continue
for at least the next few hours. Downstream of the ongoing storms,
the mesoscale environment is characterized by 1500-2500 J/kg of SB
CAPE, PWATs of 1.3-1.7" (near the 90th percentile, per PBZ
sounding climatology), and effective bulk shear of 35-45 kts.

18z HREF guidance has done a rather poor job with the evolution of
convection this afternoon, but more recent HRRR runs (since 18z)
have done a better job assimilating and propagating the ongoing
convection. These runs suggest that short-term totals of 2-3" will
continue, and associated (3-hr) FFG indicates values as low as
1-2" across the downstream portions of the Appalachians. For these
reasons, additional scattered instances of flash flooding are
considered likely (with the majority of activity ending by 06z).

Churchill

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!54OTEBaOrHG7OkZhKl5VejpsfluseiPTw2p0YAQcD25apGORxnf2Um9pM7h60-2aWdeS=
M05HMRmegIFy8leiiudTF-I$  for graphic product...

ATTN...WFO...CTP...LWX...PBZ...RLX...

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

LAT...LON   41017929 40937835 40387798 39227896 38827994=20
            38948103 39198175 39528189 39878181 40248148=20
            40418075 40747998=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to
https://lists.illinois.edu and use the "Unsubscribe" link.  Otherwise email
Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.14-Linux
 * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

.