Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Thu May 18 2023 23:37:25

AWUS01 KWNH 182337
FFGMPD
TXZ000-OKZ000-KSZ000-COZ000-NMZ000-190535-

Mesoscale Precipitation Discussion 0311
NWS Weather Prediction Center College Park MD
736 PM EDT Thu May 18 2023

Areas affected...Southeastern CO...Southwestern KS...OK/TX
Panhandle

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

Valid 182335Z - 190535Z

Summary...Localized 1-2"/hr rainfall rates to continue, isolated
to widely scattered instances of flash flooding are likely.

Discussion...A low-amplitude shortwave trough is providing lift
and forcing for the proliferation of convection along the Front
Range of CO and into the Central High Plains late this afternoon.
An associated frontal zone is providing enhanced low-level
convergence on the mesoscale, and instability is sufficient for
thunderstorm activity with surface-based CAPE of 500-1000 J/kg.
Precipitable water values range from 1.0-1.2 inches (between the
90th percentile and the max moving average, per DDC and AMA
sounding climatology) and effective bulk shear generally ranges
from 30-40 kts (with curved hodographs favoring some right-moving
supercells initially, but cell mergers are increasingly leading to
storm consolidation/organization with bowing and linear segments
taking over). Locally hourly rainfall has been as high as 1-2",
primarily where deviate cell motions have been slower (but
increasingly also where convection is able to train from
west-to-east along the frontal zone).

Going forward into this evening, expect localized (isolated to
widely scattered) instances of flash flooding to continue across a
fairly large section of the Central High Plains (generally
encompassing southeastern CO, southwestern KS, and portions of the
OK/TX Panhandles). FFGs are quite varied across the region, but
are as low as 1.5-2.0" (over 3-hr) for some areas. The HRRR has
generally underdone precipitation amounts so far this afternoon,
but even still depicts additional localized totals of 2-4" through
the evening. The HREF probabilitiy-mathced mean (PMM) is likely
providing a better depiction of our expectations, with widely
scattered totals of 2-4" and isolated totals as high as 3-5".

Churchill

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!_Y4H1fLvf1UxNK-g-fZ6ujODabCJ8rY6ymqa5VtqJSOisL5SKbh1CXqpTnvhWGf9JcJl=
f9HAzTiscFACdkwBwKELQQE$  for graphic product...

ATTN...WFO...ABQ...AMA...BOU...DDC...GLD...OUN...PUB...

ATTN...RFC...ABRFC...MBRFC...NWC...

LAT...LON   38970145 38850044 38719983 38269962 37589969=20
            36839997 35790015 35210066 35020177 34990291=20
            36040307 36960316 37340390 37940447 38630389=20
            38860332 38960241=20

=3D =3D =3D
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