Edna, Iowa Weather Forecast Discussion

189
FXUS63 KFSD 220802
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
302 AM CDT Mon Sep 22 2025
.KEY MESSAGES...
- Patchy areas of fog will be possible mainly north of I-90
  through mid-morning. With visibilities of a mile or less at
  times, be prepared for rapid changes in visibility over short
  distances.
- Additional chances for showers and thunderstorms are expected
  this afternoon and evening mainly south of I-90. A few storms
  may become severe with up to ping-pong ball (1.5") size hail
  and damaging wind gusts up to 60 mph being the primary threats.
- A pattern shift will lead to much quieter conditions and
  temperatures near to just above normal with highs mainly in
  the 70s to 80s.
&&
.DISCUSSION...
Issued at 258 AM CDT Mon Sep 22 2025
Another warm day ahead! Taking a look across the area, a few spotty
showers and thundershowers continue early this morning across the I-
90 corridor mostly in response to lingering lift associated with a
passing wave and a nocturnal 925mb LLJ. While this spotty activity
could fester through about daybreak, should see things gradually
diminish as the LLJ weakens. From here, could see a few areas of
patchy fog develop across areas north of I-90 this morning as
surface winds become light and variable. While visibilities of a
mile or less will be possible with locally dense patches especially
across southwestern MN, should things gradually clear up between
daybreak to mid-morning (9 am). Looking into the rest of the
day, quieter conditions will temporarily return from the late
morning to early afternoon as temperatures peak in the 70s to
low 80s for the day. However, our focus will shift towards our
precipitation chances (30%-50%) from the early afternoon onwards
as a shortwave intersects a stationary boundary south of I-90
triggering showers and thunderstorms.
Looking at the CAMs, there is still some lingering uncertainty as to
where the southeastward progressing boundary sets up once the wave
arrives which has led to two specific camps of solutions. The first
camp (HRRR & RAP13) has convection initializing closer to the I-90
corridor along the front and gradually progressing southwards
through the evening. The second camp (ARW, Fv3, and NAM Nest) has
scattered showers initially developing across the Missouri River
Valley with a developing surface low. However, as this low
intersects the boundary; stronger convection should take off in
northwestern IA and portions of the lower Missouri River Valley then
gradually progresses southeastwards during the evening. While both
camps are feasible solutions, still leaning towards the second camp
of solutions given how things have been trending southwards over the
last few days. Nonetheless, given the 1500-2500 J/km and 20-30 kts
of shear; a few stronger storms remain possible with the main
hazards being up to ping-pong ball sized hail (1.5") and damaging
winds up to 60 mph. With all this in mind, the main timeline for any
stronger activity will likely be between 3 pm to 9 pm. However, if
things can develop further south (closer to highway-20); the window
will narrow considerably to 3pm to 7 pm. From here, should see
things quiet down during the overnight hours as temperatures drop
into the low to upper 50s for lows.
Looking into the midweek onwards, a pattern shift begins to take
shape as the departing long-wave trough is replaced by building
upper-level ridging. With this likely keeping our precipitation
chances at bay for a while, expect temperatures to continue to sit
in the 70s to low 80s through the weekend. With this in mind, this
would be a good time to finish any lingering outdoor projects and/or
plan some outdoor activities so get out an enjoy the beautiful
conditions! Lastly, we`ll have to continue to monitor for fire
weather concerns over the next few weeks as limited moisture and
warm temperatures should begin to dry out our fuels overtime.
&&
.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1052 PM CDT Sun Sep 21 2025
Isolated showers are ongoing in portions of northwestern Iowa and
southwestern Minnesota. These are expected to slowly drift east out
of our area over the next few hours. These storms have a history of
producing severe hail and may continue to do so until they move out,
after 22.08Z. Under any storms ceilings may degrade to MVFR to
IFR with unpredictable winds. Storms are not currently expected
to impact any TAF sites.
After storms have ended clearing skies will allow for some patchy
dense fog to develop. Visibility may drop below 1 SM at times,
especially for areas of Central South Dakota, and along and north of
Highway 14.
Finally, Monday afternoon into the evening, showers and
thunderstorms may develop mostly south of I-90. KSUX is the most
likely site to experience these storms, and so have entered a Prob30
group for Monday evening. These storms will drift south through the
end 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