Peterson, Iowa Weather Forecast Discussion

600
FXUS63 KFSD 230353
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
1053 PM CDT Mon Sep 22 2025
.KEY MESSAGES...
- Scattered thunderstorms possible late this afternoon into the
  early overnight hours. Ping pong ball-sized hail and wind
  gusts to 60 mph are the main threats from the strongest
  storms.
- A persistent seasonally warm pattern will be in place Tuesday
  through early next week with very small chances for
  precipitation.
- Patchy fog possible on Tuesday morning.
&&
.DISCUSSION...
Issued at 206 PM CDT Mon Sep 22 2025
The tail end of an exiting wave will bring a small chance for
some diurnally driven thunderstorms into parts of northwest IA
late this afternoon into the evening. With close to 2000 J/kg
CAPE in this environment and fairly weak shear, a few severe
storms will be possible. The main threats from the strongest
storms would be ping pong ball-sized hail and wind gusts to 60
mph. During the evening and night-time hours a wave will move
through NE and another shot for storms along the NE/SD border
towards Sioux City. These storms may also produce a few stronger
updrafts with weak shear and about 1500 J/kg CAPE.
Once the thunderstorm threat passes tonight a ridge of high
pressure will settle into northern and central SD. This will
bring some cooler morning readings with at least a small chance
of a few locations sneaking into the upper 40s near highway 14.
With a marginally moist ground in places and light winds, some
patchy fog will again be possible, with the better chances near
and north of I-90.
Cooler high pressure builds south and brings about a seasonally
warm day on Tuesday with relatively light winds. A small
corridor around highway 81 and I-29 may see some spotty
diurnally driven showers Tuesday afternoon. Skinny CAPE with
values less than about 300 J/kg. Fairly low confidence in this
occurrence.
A dry and warm pattern develops Wednesday into the weekend with
very little if any chance for precipitation. One stronger wave
does move by to the north on Friday and brings a nice warm nose
into the area, so a very small chance for a shower or
thunderstorm on Friday. With this warm nose Friday, should also
prove to be the warmest with some mid and possibly upper 80s for
highs. Another warm nose may sneak into the area Sunday night
into Monday and bring another very small chance, but once again
too low to mention. Outside of Friday, Wednesday through early
next week should see highs in the 70s to lower 80s.
&&
.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1052 PM CDT Mon Sep 22 2025
VFR conditions across the region currently. There is a low chance
that showers may redevelop into the southern portions of our region
over the next few hours. Have included a Prob30 group for showers
between 23.06-23.09Z.
Winds become light and variable overnight allowing for patchy
dense fog development. As a result, a brief period of MVFR
ceilings and visibilities is possible toward dawn and may linger
into the mid- morning. Winds remain light with mostly clear
skies for the remainder of the period.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...05
AVIATION...AJP

NWS FSD Office Area Forecast Discussion