North Sioux City, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

433
FXUS63 KFSD 240440
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1040 PM CST Tue Dec 23 2025

.KEY MESSAGES...

- Areas of fog will persist through the early morning hours of
  Wednesday mainly along and east of highway-59. With
  visibilities of 1/2 mile or less expected at times, be
  prepared for rapid changes in visibility.

- Midweek temperatures have trended cooler, but still 10-20
  degrees above normal for much of this holiday week. Turning
  windy and colder this weekend, with wind chills likely
  dropping below zero by Sunday morning.

- Outside of some low-end drizzle potential, dry weather will
  prevail through Christmas Day. May have to watch for light
  wintry precipitation during the post-holiday travel period,
  however confidence in timing/location details remains low.

- Elevated fire danger will be possible on breezier days in
  snow-free areas, mainly across south central South Dakota
  through the Missouri River Valley.

&&

.UPDATE...
Issued at 1026 PM CST Tue Dec 23 2025

Areas of fog and/or low stratus continue to spread across areas
along and east of U.S. highway-59 this evening. With observations
continuing to show visibility reductions of a 1/2 to 1 mile,
decided to issue a dense fog advisory for portions of southwestern
MN and northwestern IA through 3 am (09z). While there is still
potential for further expansion southwards, some uncertainty
remain on just how far south the lower visibilities will extend
mainly due to slight increases in south-southeast surface winds.
If surface winds trend weaker, areas of locally dense fog could
spread as far south as Cherokee and Storm Lake in Iowa. If vice
versa is true, the areas of dense fog would dissipate in
southwestern MN while areas in northwestern IA continue to sit
in the soup. Either way, rapid reductions in visibility are
expected in the previously outlined areas so make sure to drive
with care.

&&

.DISCUSSION...
Issued at 238 PM CST Tue Dec 23 2025

It`s been another mild December day as temperatures have climbed
into the mid-30s to mid-40s this afternoon. The only exception is
along the Highway-14 corridor where clouds have kept temperatures in
the mid-20s to low-30s. Quiet weather is expected for the remainder
of this afternoon and evening, so those with last minute gift
shopping plans should be good to go weather-wise! For tonight,
look for some patchy fog in areas that saw the most snowmelt
today, which would be in places where the greatest snow depth
remains. For our area, this is in northwest Iowa along and east
of a Sheldon to Storm Lake line.

Southerly flow returns to the area as a surface high slides
east of us tonight, and warm air advection at 850 mb also looks
to make a return. This combined with increasing cloud cover will
all lead a mild night for December standards, with lows ranging
from the mid-20s in southwest Minnesota to the mid-30s in
south-central South Dakota. This increasingly southerly flow
will also bring more moisture into the area tomorrow morning,
especially over northwest Iowa where dew points are set to rise
into the 40s by noon. This will lead to widespread stratus
development in northwest Iowa through tomorrow morning, which
could be deep enough to lead to some drizzle. Confidence was not
high enough to include drizzle in the forecast as the depth of
the stratus only marginally supports it at this time, but
trends will be monitored. If drizzle does develop, we will also
have to watch temperatures closely. But as of right now we do
look to remain above freezing if and when any drizzle occurs,
though it could get close if drizzle develops earlier in the
morning hours. Otherwise, clouds from overnight tonight will
gradually push eastward and clear out in plenty of time to allow
for highs to be near 60 in parts of south-central South Dakota.
Elsewhere, temperatures will still be mild for this time of
year, reaching the 40s for most of us along and east of the
James River.

High temperatures continue to trend cooler for Christmas Day as
guidance continues to indicate a large part of the area being stuck
under stratus. Highs still look to be much above average regardless,
with afternoon temperatures on Christmas ranging from the mid-50s in
south-central South Dakota to the upper-30s over southwest
Minnesota. There will still be decently strong WAA at 850 mb
ongoing on Christmas Day, so if stratus is able to break away
even for a little bit, temperatures will end up warmer than
currently expected. There is still some uncertainty as to
whether or not the stratus deck will be deep enough to produce
drizzle, which will mean another need to closely watch
temperatures especially if there is drizzle in the early morning
hours. For now, left drizzle out of the forecast for Christmas
Day.

An upper-wave will pass through the area Thursday night, with a
surface low developing in response. Currently expecting that most of
the precipitation with this system will be east of the area,
with ensemble probabilities of measurable precipitation
generally less than 20% mainly east of US Highway-75. The EC AI
model is most aggressive with this, showing a 20-40% of
measurable precipitation along and east of I-29, but this
remains an outlier at this time. Friday looks to be a mild and
quiet day as we`ll see some slight ridging aloft, with highs
ranging from the low-60s in south-central South Dakota to the
low-40s in southwest Minnesota.

A strong trough will dig out of the Canadian Rockies into the
northern Plains Friday night into Saturday, helping to move a strong
cold front through the area. Once again, guidance isn`t too excited
for us precipitation-wise, with ensemble probabilities of measurable
precipitation around 20% for late Saturday into Sunday, focused
north of I-90. Confidence is lower as to whether or not we`ll see
any impacts from this system since it`s still a few days out,
so be sure to keep up to date with the latest forecast
especially if you have any post-holiday travel plans.
Temperatures may still be mild on Saturday depending on the
timing of the frontal passage and the cold air advection that
follows, with highs currently forecast to be in the 40s to
low-50s. This may be lowered or even raised slightly as
guidance comes into better agreement with the timing of the
front and secondary surge of CAA that follows. After the cold
front pushes through, the aforementioned strong CAA will follow
and cause a big drop in temperatures heading into Saturday night
when we look to see lows down to the single-digits to teens.
Winds will also likely be elevated with this push of cold air,
with some guidance indicating 45-60 mph winds at 850 mb. The
latest NBM shows gusts up to 35-40 mph at the surface Saturday
night into Sunday, with up to a 20-30% chance of gusts over 45
mph. This will likely lead to below zero wind chills for much of
the area Saturday night through Monday morning, so get ready to
bring those heavier coats back out!

Ridging aloft will begin to try building back into the region during
the first part of the next work week as an upper-low meanders
over southeastern Canada and New England. This will allow for us
to become milder once again by Tuesday as we look to see highs
climb back into the 30s and perhaps the 40s for parts of the
area. Guidance indicates a shortwave riding the western
periphery of the aforementioned New England upper-low, which
could bring some precipitation to our area by Tuesday night
into Wednesday, though confidence remains low in any details
owing to this being a week out.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1030 PM CST Tue Dec 23 2025

Mostly VFR with occasional IFR to LIFR vsby and cigs are
expected this TAF period. Taking a look at satellite imagery,
high level cirrus continues to sit over the area with a more
concentrated area of low-level stratus/developing fog sitting
over portions of southwestern MN and northwestern IA. While the
developing areas of fog could lead to periods of IFR to LIFR
vsbys and cigs, should see coverage gradually shrink by mid-
morning. From here, areas of stratus and/or fog will redevelop
during the afternoon hours on Wednesday mainly across northwestern
IA initially then becoming more widespread overnight. Lastly,
southerly winds through the day on Wednesday will become more
light and variable by Wednesday night.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...Dense Fog Advisory until 3 AM CST Wednesday for MNZ080-081-089-
     090.
IA...Dense Fog Advisory until 3 AM CST Wednesday for IAZ003.
NE...None.

&&

$$

UPDATE...05
DISCUSSION...Samet
AVIATION...05