Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Sun Sep 24 2023 02:28:17

AWUS01 KWNH 240228
FFGMPD
WIZ000-MNZ000-240725-

Mesoscale Precipitation Discussion 1099
NWS Weather Prediction Center College Park MD
1026 PM EDT Sat Sep 23 2023

Areas affected...Portions of Central and Southern MN

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

Valid 240225Z - 240725Z

SUMMARY...Heavy showers and thunderstorms may pose some urban
flash flooding concerns over the next several hours.

DISCUSSION...The latest radar imagery shows an axis of heavy
showers and thunderstorms generally expanding in coverage across
areas of central and southern MN out ahead of a strong mid to
upper-level trough ejecting slowly east out across the northern
Plains.

A combination of strong dynamical forcing/divergent flow aloft
along with the northward advance of modest instability with MLCAPE
values of 500 to 1000 J/kg ahead of an occluded low center will
continue to favor clusters of heavy showers and thunderstorms
going well into the overnight hours.

Rainfall rates more recently with the activity to the south and
west of the Minneapolis-Saint Paul (MSP) metropolitan area have
been increasing, with some cells producing rates of up to 1.5 to 2
inches/hour.

There is a fair amount of spread in the hires model guidance with
the placement of the more organized convection and overall
rainfall potential, but generally the consensus supports locally
as much as 3 to 4 inches of rain with isolated heavier amounts
over the next several hours.

The antecedent conditions remain quite dry, based off the latest
NASA SPoRT soil moisture anomalies and with streamflows generally
below average. However, some of these heavier rains over the next
several hours should impact some notably urbanized locations
including the Minneapolis-Saint Paul metropolitan area and
adjacent suburbia. Therefore, there is a concern for urban flash
flooding and at least an isolated threat more regionally for
runoff problems where these heavier convective clusters set up and
potentially train over the same area.

As instability wanes later in the night, the convection should
gradually weaken and this will eventually allow for any flash
flooding concerns to diminish.

Orrison

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!6-PTj9mi4cKCbhzENQINzn7ubT8UV6Kfl1Aor-RlEbpmGEii8apJg4xgfYAqdW1yBoq8=
HrX0KsmzW4wd-IXLHp1-eg0$  for graphic product...

ATTN...WFO...ARX...DLH...MPX...

ATTN...RFC...NCRFC...NWC...

LAT...LON   46119361 45879295 45159264 44639254 44109256=20
            43729303 43869389 44349418 45179436 45909413=20
=20=20=20=20=20=20=20=20=20=20=20=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 3.14-Linux
 * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

.