Severe Thunderstorm Warning 69, NWS Des Moines, IA

Area Forecast Discussion
National Weather Service Des Moines IA
Issued by National Weather Service Twin Cities/Chanhassen MN
328 PM CDT Wed Apr 23 2025

.KEY MESSAGES...

- A marginal risk for severe wind and hail as storms redevelop  this
  evening across central and southern Iowa.

- More widespread rain on Thursday with over an inch expected
  and some more isolated locations seeing over an inch.

&&

.DISCUSSION...
Issued at 326 PM CDT Wed Apr 23 2025

Morning showers & thunderstorms have dissipated and left behind
partly cloudy skies for much of Iowa. Modest instability remains in
place and our quasi-stationary boundary will gradually lift north
over the next 24 hours. Additional thunderstorm & shower development
will begin this evening into Thursday. SPC's SWO day 1 maintains a
Marginal Risk (1 out of 5) for a few strong to severe storms that
may be capable of producing isolated gusty winds & large hail,
similar to what we saw yesterday evening. Forecast soundings would
indicate our MUCAPE drops off after 03Z tonight & any severe weather
threat likely tapers off too.

Thursday & Friday continue the theme over the past few days with a
rather gloomy outlook that features additional rain & storm chances.
The culprit shortwave trough will eject out of the Plains on
Thursday. This will prompt the sfc low over the western OK to move
northeast towards the Great Lakes region Thursday afternoon. An
subtle increase in moisture will occur ahead of this leading to PWAT
values 1.0-1.2" Thursday PM. The sfc low will struggle as a sfc high
pressure drops into the northern Plains and acts to suppress our sfc
low. Enough forcing will be present to bring a more organized round
of showers & Thunderstorms Thursday afternoon into early Friday.
Precipitation amounts over the next 48 hours of an inch or more seem
likely for much of Iowa. Severe weather potential Thursday and
Thursday night will be very low as this becomes a stratiform-driven
rain event vs a convective rain event. Precipitation will exit as
the sfc low shifts into the southern Great Lakes on Friday and will
leave behind drier weather & seasonable temperatures for Friday &
Saturday.

Sunday & Monday will see the sfc high pressure move east into the
eastern CONUS. This will allow for southerly return flow set up over
Iowa and begin to usher in moisture & warmer temperatures. This will
lead to more shower and storm chances returning Sunday into Monday.
Our pattern remains fairly active into next week, with SPC
maintaining a day 6 15% risk (slight risk) for severe weather Monday
into Tuesday as a wound up low pressure lifts into the area. More on
this system will be provided in the coming days.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1247 PM CDT Wed Apr 23 2025

VFR conditions this afternoon as skies are mostly clear across
the region, and winds are light with a weak boundary draped
across the region. This boundary will be the focus for scattered
showers and thunderstorms later this evening and overnight.
Chances for thunderstorms exist into Thursday as well. Overall
expect VFR conditions to continue into Thursday, except for
MVFR/IFR conditions where there are storms.

&&

.HYDROLOGY...
Issued at 326 PM CDT Wed Apr 23 2025

Widespread rainfall expected across central Iowa (80-90%)
Thursday continues to signal an increasing potential for
additional rainfall totals around an inch, with an isolated
higher amount near 1.5’’ across central and northern Iowa. River
responses per HEFS guidance suggests that a rise above Action
Stage is likely (70-90%) at Shell Rock and Cedar Rivers Thursday
into Friday. Though the likelihood for additional sites to see
river flow exceedance is on the lower end (<=30) at the Iowa
River, Des Moines River, and Raccoon River, rises at and above
the Action Stage threshold if higher rainfall amounts were to
occur. Close monitoring will continue to watch for this
potential.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
None.

&&

DISCUSSION...BPH
AVIATION...JRB
HYDROLOGY...Bury

Hazardous Weather Outlook
National Weather Service Des Moines IA
Issued by National Weather Service Twin Cities/Chanhassen MN
334 PM CDT Wed Apr 23 2025

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-
081>086-092>097-242045-
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Sac-Calhoun-
Webster-Hamilton-Hardin-Grundy-Black Hawk-Crawford-Carroll-Greene-
Boone-Story-Marshall-Tama-Audubon-Guthrie-Dallas-Polk-Jasper-
Poweshiek-Cass-Adair-Madison-Warren-Marion-Mahaska-Adams-Union-
Clarke-Lucas-Monroe-Wapello-Taylor-Ringgold-Decatur-Wayne-
Appanoose-Davis-
334 PM CDT Wed Apr 23 2025

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...This afternoon and tonight

Scattered thunderstorms this this evening. A few may be strong
with gusty winds, hail, and locally heavy rains.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Additional chances for thunderstorms Thursday, and again early
next week. Some storms could produce heavy rain, along with a
chance for severe weather.

.SPOTTER INFORMATION STATEMENT...

Spotters may be needed this evening, and then again later in the
work week.

BPH

Special Weather Statement
National Weather Service Des Moines IA
Issued by National Weather Service Duluth MN
553 PM CDT Wed Apr 23 2025

IAZ057-058-232330-
Guthrie IA-Audubon IA-
553 PM CDT Wed Apr 23 2025

...A strong thunderstorm will impact portions of southwestern Guthrie
and eastern Audubon Counties through 630 PM CDT
...

At 553 PM CDT, Doppler radar was tracking a strong thunderstorm 6
miles east of Audubon, moving southeast at 20 mph.

HAZARD...Winds in excess of 40 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

This storm will remain over mainly rural areas of southwestern
Guthrie and eastern Audubon Counties, including the following
locations... Audubon County Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 4180 9484 4171 9445 4150 9469 4150 9473
      4169 9499
TIME...MOT...LOC 2253Z 297DEG 16KT 4169 9481

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

NLy

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