Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Mon May 29 2023 19:19:21

AWUS01 KWNH 291919
FFGMPD
DEZ000-MDZ000-VAZ000-DCZ000-WVZ000-300000-

Mesoscale Precipitation Discussion 0378
NWS Weather Prediction Center College Park MD
318 PM EDT Mon May 29 2023

Areas affected...Central & Southern Delmarva Peninsula... Southern
MD...D.C...and Northern VA...

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

Valid 291920Z - 300000Z

SUMMARY...Narrow band of training warm cloud showers/thunderstorms
may track through populated areas with streaks of 2-3" totals
posing instances of localized flooding.

DISCUSSION...Regional RADAR and GOES-E Visible imagery shows a
line of shallow convection stretching from S Delaware across to
central MD toward DC.  RAP meso-scale analysis denotes a pocket of
enhanced deep layer moisture of 1.5" Total PWat including a band
of mi-60s to even low 70s Tds tracking along a narrow but well
defined boundary.  This boundary appears to extend through 700mb
with solid confluent 15-20kt flow.  Satellite trends support a
tightening of the cloud deck from the north-northeast indicative
of a weak back-door boundary to enhance moisture flux/confluence.
Even with cloud cover, weak southerly flow is advecting areas of
enhanced instability with a small reservoir of 2000-2500 J/kg of
SBCAPE across the southern Delmarva into southern MD and the
northern Necks of VA.   Additional banding features appear to be
developing in the core of this instability axis and with a similar
steering flow regime may allow for training further south into
northern VA as well.=20

Banding through Southern Anne Arundel county has displayed
1.5"+/hr rates supported by backyard weather observations.  Length
of the band and slow southward drift with the influence of the
back-door flow, may allow for 1-3 hours, with streaks of 2-3"
possible.  This is near FFG values in the rural areas, but given
proximity to urban settings, particularly DC, scattered flooding
may become a concern over the next 3-5 hours.

Gallina

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!5AsmPI-0ZpG5MYcKUqR9UqHG3RzPgVSYRJ5NQoJgSwGC3jPie6qM_3NlsXSWG6ohzxiZ=
JXqhVxuXQgCPqP0sn3ncgfs$  for graphic product...

ATTN...WFO...AKQ...LWX...PHI...

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

LAT...LON   39207833 39157712 38977640 38807589 38667513=20
            38447497 38037536 37697568 37547641 37687739=20
            37967853 38587880=20

=3D =3D =3D
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