Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Tue Aug 12 2025 01:13:06

AWUS01 KWNH 120113
FFGMPD
INZ000-ILZ000-120541-

Mesoscale Precipitation Discussion 0913
NWS Weather Prediction Center College Park MD
912 PM EDT Mon Aug 11 2025

Areas affected...northeast IL

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

Valid 120111Z - 120541Z

Summary...Showers and thunderstorms have begun to develop in
north-central IL, trying to attain a training signature as they
aim towards Chicagoland and grow in coverage.  Hourly rain amounts
to 2.5" with local totals to 4" are possible, which would be
problematic in urban areas.

Discussion...since 2330z, showers and thunderstorms have been
developing, slowly growing in scale, and trying to align south and
east of Peru IL within an area of low-level convergence.  Hourly
rain amounts in spots have exceeded 1.5" per radar estimates.=20
Precipitable water values are ~1.9 per GPS data.  ML CAPE is
2500-3500 J/kg to their south.  Effective bulk shear of 25-30 kts
is trying to align the activity.

The 12z & 18z HREF runs were insistent on this activity forming,
whereas the 06z and 12z REFS had a much weaker signal, so used the
HREF as a guide (outside of the IA contribution which is
underperforming on the HREF).  The convective packet is moving
east-northeast at 15-20 kts, with individual cells moving quicker
than the packet as a whole.  Hourly rain amounts to 2.5" with
local totals to 4" are possible over the next 3-4 hours.  This
could lead to problems in Chicagoland tonight.

Roth

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!8D0Dkr8qJgiiOsyFHMaTOAUmevGRDrB_k1_YukUqwjPYMd4mKpJvJOsTsDOnIOQO_dxT=
KHM2l4AHhS_brtmO0U5dzfo$  for graphic product...

ATTN...WFO...DVN...ILX...LOT...

ATTN...RFC...MSR...NWC...

LAT...LON   42208780 41668747 40738957 40698991 40858984=20
            41598892=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 3.28-Linux
 * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

.