Madison, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

037
FXUS63 KFSD 110908
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
408 AM CDT Mon Aug 11 2025

.KEY MESSAGES...

- Areas of smoke, surface and aloft, will create hazy skies with
  occasional impacts to air quality through early Tuesday. Minor
  visibility reductions are also possible at times.

- Wednesday night into Thursday morning may bring a few
  thunderstorms to areas north of I-90, with the better chance
  closer to highway 14. Severe weather risks are low.

- Thursday into Saturday will see increased temperatures and dew
  points return, with Moderate/locally Major Heat Risk. Highs in
  the upper 80s to mid 90s and dew points in the 70s may result
  in 100+ degree heat indices for some locations.

- Although uncertainty remains in details, thunderstorm chances
  return late week into this weekend. Pattern favors nighttime
  to early morning thunderstorms, with locally heavy rain and
  perhaps some severe storms possible.

&&

.DISCUSSION...
Issued at 408 AM CDT Mon Aug 11 2025

TODAY-TUESDAY: Main concern early this week will be another
round of wildfire smoke which has filtered into the northern
Plains from Canada. Latest HRRR/RRFS projections hang onto areas
of smoke both aloft and at the surface through today, slowly
exiting east tonight through Tuesday morning as a weak cool
front pushes through the forecast area. Aside from shallow fog
which is also reducing visibility early this morning, expect
area visibility reports in the 3-5 mile range are generally from
the surface smoke with air quality readings largely in the
yellow to orange range (Moderate to Unhealthy for Sensitive
Groups) as of 3 am. However, upstream air quality observations
in central-northeast SD/western ND are in the red (Unhealthy)
category, and will have to watch for worsening air quality and
perhaps visibility as we move through the morning.

Other than the smoke, today and Tuesday look to be relatively
nice days with modest humidity levels for this time of year and
temperatures near to slightly below normal. A subtle wave may
produce some sprinkles north of I-90 late this afternoon/evening
but most areas should remain dry.

WEDNESDAY-THURSDAY: Rising heights aloft and increasing south
winds in the low levels will allow warmer air to slowly build
into the region midweek. Still seasonal high temperatures in the
80s Wednesday will warm into the mid 80s to mid 90s by Thursday,
accompanied by some increase in low level humidity as well. The
combination of warmer temperatures and higher dew points may
push heat indices above 100F in some areas Thursday afternoon,
so will have to monitor trends for possible heat headlines.

Placement of the mid-level thermal ridge should keep rain chances
largely north of the area, though a modest wave seen in several
model solutions could brush our northern counties with some
storms Wednesday night into early Thursday. At this time, the
greater risk for a few strong-severe storms looks to remain
north of our forecast area, but if the wave tracks a bit farther
south we will have to monitor potential into the Highway 14
corridor Wednesday night.

FRIDAY-SUNDAY: The heat peaks Friday, with a transition to
southwest flow aloft potentially bringing us back into a more
active pattern by Friday night into the weekend. Seasonably
warm temperatures and abundant low level humidity will fuel
ample instability, but similar to this past weekend, mid level
temperatures may be too warm to allow convective development in
our area during peak heating. Instead, could more likely see
development to our west move east into our forecast area during
the nighttime to early morning hours. Still several days away,
so details regarding storm location and severe potential are
uncertain. However, ensembles show precipitable water values
increasing above the 90th percentile of climatology with a
potential southerly low level jet through eastern Nebraska,
which could support at least a locally heavy rain threat.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1052 PM CDT Sun Aug 10 2025

Wildfire smoke continues to impact the area, though most of it is
now aloft and thus surface visibilities have generally been
improving. Still can`t rule out some drops to 4-5 SM due to smoke
through daybreak. Otherwise, patchy fog could also cause MVFR
visibility restrictions early Monday morning (roughly 11Z-14Z),
mainly for areas near and east of I-29. Still some uncertainty
in where fog will be most dense, but enough confidence to keep
MVFR fog at KSUX and VFR fog at KFSD at this time. Trends will
be monitored overnight.

A cold front begins to move into the area towards the end of the
period, which could fire off a few showers and an isolated
thunderstorm mainly north of I-90, but confidence in shower coverage
and timing is not high enough to include at KHON at this time. Winds
will be light and variable tonight, with winds increasing to 5-10
kts out of the south/southwest Monday afternoon.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

$$

DISCUSSION...JH
AVIATION...Samet