Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Wed Sep 20 2023 12:30:46

AWUS01 KWNH 201230
FFGMPD
MOZ000-ARZ000-TXZ000-OKZ000-201829-

Mesoscale Precipitation Discussion 1087
NWS Weather Prediction Center College Park MD
830 AM EDT Wed Sep 20 2023

Areas affected...eastern Oklahoma and far western Arkansas

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

Valid 201229Z - 201829Z

Summary...Isolated flash flood potential should continue through
the early afternoon hours.

Discussion...Scattered convection persists on the southwestern
periphery of a mesoscale convective vortex centered over central
Missouri.  The storms continue to be supported by ascent
associated with the vortex, appreciable low-level flow (especially
in eastern Oklahoma), and steep mid-level lapse rates (7+ C/km
generally from Tulsa to McAlester and points westward). While
recent radar mosaic imagery indicates a lack of focused/banded
convection for training and extreme rainfall rates, cells are
repeating across localized areas and resulting in spots of 1-2
inch/hr rain rates (and 3-3.5 inch/3-hour rain rates) that have
resulted in areas of MRMS Flash responses (especially in
northeastern Oklahoma).

Models/observations suggest that the pattern of backbuilding
convection across eastern Oklahoma (generally along and east of
the Tulsa-to-McAlester/US 75 corridor) should continue, with
ongoing support for updrafts resulting from steep mid-level lapse
rates and instability near and just west of that axis.  FFG
thresholds (in the 2.5-4 inch/hr range) and dry antecedent
conditions preclude a more widespread flash flood risk today,
although isolated instances of higher rain rates and excessive
rainfall should continue to be a threat through at least 1830Z.

Cook

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!-kKsRZ9uqQIMTY6OAVWFHNg5i4iCL3eCKVGbRKSqMnZjes4neH42YsYETCi8rJHTrOZ0=
zOYmTqN3pZG7PntYFlHB0BI$  for graphic product...

ATTN...WFO...LZK...OUN...SGF...SHV...TSA...

ATTN...RFC...ABRFC...LMRFC...NWC...

LAT...LON   36809553 36599436 35919392 34559382 33889432=20
            33999588 35179631 36009610=20

=3D =3D =3D
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