Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Tue Sep 23 2025 01:06:50

AWUS01 KWNH 230106
FFGMPD
NEZ000-SDZ000-230630-

Mesoscale Precipitation Discussion 1119
NWS Weather Prediction Center College Park MD
905 PM EDT Mon Sep 22 2025

Areas affected...Southwest SD...Northwest NE

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

Valid 230105Z - 230630Z

SUMMARY...Slow-moving heavy showers and thunderstorms may result
in a threat for isolated areas of flash flooding over the next
several hours.

DISCUSSION...The latest GOES-E IR satellite imagery shows cooling
convective tops across southwest SD in response to a combination
of amplifying mid-level shortwave energy and a nose of moderate
instability focused near a front. MLCAPE values of 1000 to 2000
J/kg are noted across the region along with an axis of moderately
strong moisture convergence.

Model guidance suggests a further amplification of mid-level
energy/height falls with a rather tight 700 mb circulation
forecast to evolve overnight along the SD/NE border with a slow
southward drift in time. This will help support a relatively
strong mid-level deformation zone around the western flank of the
low center, with a favorable axis of moisture convergence and some
frontogenetical forcing working in tandem with the available
instability to support additional concentrated focus for heavy
showers and thunderstorms.

Rainfall rates with the convection over the next few hours will be
capable of reaching 1 to 2 inches/hour, and with the slow
cell-motions, some localized storm totals may reach 3 to 4 inches
which is consistent with the latest hires model guidance. An
isolated threat for flash flooding will exist where the heavier
rainfall totals materialize over the next several hours.

Orrison

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!591XiKxBXRChhYw7AD4xj8WZr883DGw6HhZ1CVNV_VSG5T2v_5HTGwA_s-p0GB7br9AN=
P0w_s-4BeL3b1zTMoEAHZlE$  for graphic product...

ATTN...WFO...CYS...LBF...UNR...

ATTN...RFC...KRF...NWC...

LAT...LON   44570340 44480281 43950219 43330120 42820105=20
            42670149 42620181 42480227 42100279 42310354=20
            43080399 43570395 44140386=20

=3D =3D =3D
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