467
FXUS63 KFSD 271855
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
155 PM CDT Mon Jul 27 2026

.KEY MESSAGES...

- Showers and thunderstorms are possible this evening into the
  overnight. Severe weather is possible over central South
  Dakota with the primary risk 65 mph wind gusts. Storms are
  expected to weaken as they move east.

- Heat indices climb to 95 to 105 today, mainly south of I-90.
  Locally higher heat indices are possible along and south of
  the Highway 20 corridor. A Heat Advisory remains in effect
  until 8 pm for areas south of I-90 into portions of southern
  Minnesota.

- Showers and thunderstorms are possible again both Wednesday
  and Thursday afternoon and evening. An isolated storm could
  be severe.

&&

.DISCUSSION...
Issued at 153 PM CDT Mon Jul 27 2026

Hot and humid conditions improve behind a cold front that passed
through the region this morning. Winds behind the front are out of
the north and a bit breezy with gusts to around 20 mph. Dewpoints
are falling rapidly to the low 60s. However, highs are still
expected to climb into the 90s and low 100s, and so Heat Index
values will be 100 to 104 degrees F. A Heat Advisory remains in
effect for areas along and south of I-90 until 8 pm CDT.

In addition to heat there is a Marginal risk (level 1 of 5) for
strong to severe thunderstorms. A shallow wave will pass through the
region, triggering storms over western South Dakota late this
afternoon into the early evening. These will travel east and begin
to impact areas of central South Dakota some time after 9 pm CDT. As
storms approach they will be encountering an increasingly stable
environment. While severe weather cannot be ruled out, the area most
likely to see any stronger storms will be west of the James River.
The main risk with storms will be damaging wind gusts of 65 mph.
Storm intensity will weaken as they continue east becoming scattered
rain showers and weak thunderstorms. Rain accumulation will be
light, a trace to a hundredth for most of the CWA. West of the James
River may see up to a tenth of an inch. Showers may linger into the
morning commute Tuesday, but impacts should be minimal.

Tuesday surface high pressure settles over central South Dakota
turning winds to the southeast. Highs will be cooler, in the 80s
east of Highway 81, and in the low 90s to the west. Dew points will
climb into the mid 60s to low 70s and will result in muggy
conditions once again. However, Heat Index values will remain below
critical. Still, it`s important to maintain proper hydration and to
take breaks out of the heat. Wednesday will be another quiet day
with highs in the 90s.

Wednesday night a short wave will work through the upper ridge
bringing chances for showers and thunderstorms. There is a very
large difference in mid-range guidance on convective parameters,
therefore the severity of the storms is uncertain. Thursday
isolated to scattered light showers will continue periodically
through the day. Thursday afternoon a stronger upper wave moves
into the region. This will result in another round of showers
and thunderstorms. Mid-range guidance continues to have a wide
range of solutions, and severity of storms is once again in
question. Over the coming days the trends will be monitored and
updates issued as details become clear.

An upper level ridge will push into the region behind the wave for
the weekend. Partly cloudy skies and highs in the 80s to low 90s
with dry conditions are expected.

One final note: Smoke from wildfires in the western US and Canada is
expected to begin to flow into the region today. This will result in
milky looking skies and a decrease in air quality. You may even be
able to smell smoke at times depending on how deeply we mix each
day. With our current upper level pattern smoke is expected to
remain in the forecast through at least the middle of the week.
People who are sensitive to air pollutants should use precautions.
For the latest on Air Quality please visit AirNow.gov.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1221 PM CDT Mon Jul 27 2026

VFR conditions are expected to prevail this period. Smoke from
wildfires in the western US and Canada will flow in on
northwest winds aloft. Skies will be partially obscured and
visibility may fall to 6sm at times due to smoke.

Winds are northeast with gusts to 17 kts. Winds will become light
and variable after sunset. Tuesday winds will remain light and
gradually become southerly.

Chances for rain this evening over central South Dakota. Some storms
could be strong to severe with wind gusts of 65 mph the primary
threat. Storms are expected to weaken and become scattered and light
as they progress east overnight. Some showers may linger into
Tuesday morning. Confidence in storms impacting any TAF sites was
too low to include at this time.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory until 8 PM CDT this evening for SDZ050-063>071.
MN...Heat Advisory until 8 PM CDT this evening for MNZ081-090.
IA...Heat Advisory until 8 PM CDT this evening for IAZ001>003-
     012>014-020>022-031-032.
NE...Heat Advisory until 8 PM CDT this evening for NEZ013-014.

&&

$$

DISCUSSION...AJP
AVIATION...AJP