463
FXUS63 KFSD 280524
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1224 AM CDT Tue Jul 28 2026

.KEY MESSAGES...

- Light showers continue to push southeastwards across the area
  this evening. Should see the showers diminish through the
  rest of the evening and early overnight hours as the push
  southeastwards. Severe storms are not expected.

- A few afternoon hours and thunderstorms are possible (30%)
  tomorrow in southwest Minnesota. Severe storms are not
  expected but the strongest storms will be capable of wind
  gusts up to 50 mph and hail up to dime size (0.75").

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

&&

.UPDATE...
Issued at 849 PM CDT Mon Jul 27 2026

Thunderstorms that have developed previously across south central
South Dakota heave considerably weakened as more stable air was
advected into the storms. Now light rain showers have pushed into
locations near and west of the James River. With the stable air in
place, think these showers will continue to weaken with
southeastward extent. This will leave mostly dry conditions for the
overnight hours with maybe a trailing light shower or two persisting
through the night. However, low temperatures will remain warm
overnight with lows bottoming out in the upper 60s and 70s. This
will keep heat indices in the low 70s overnight, continuing warm and
humid conditions.

With the influence of a surface high pressure system in place
tomorrow, high temperatures will be cooler from what we have seen
the past few days with highs warming to the 80s to low 90s. Latest
hi-res guidance shows the potential for diurnally driven storms to
develop across southwest Minnesota tomorrow afternoon. Despite the
influence from the surface high, winds at the surface may be light
and variable just enough to create a small convergence zone along
the Buffalo Ridge. Forcing looks to remain weak but the right
entrance region of an upper level jet will be residing over the
forecast area, providing some upper level support. Instability will
be sufficient but deep layer shear values will be weaker on the
order of 30 knots or so. However, vertical shear values do
strengthen higher up in the atmosphere, so if storms are able to
develop along this convergence zone, they could be stronger with
wind gusts to 50 mph and hail up to dime size. This activity will
weaken during the evening hours as the boundary layer
stabilizes.

&&

.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 /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1223 AM CDT Tue Jul 28 2026

VFR conditions begin the TAF period. Showers persist for locations
along and west of the James River. These showers will wane over the
coming hours as they push southeastwards. A few light showers could
persist through the night but am not expecting them to impact any
TAF sites. Dry conditions will return for tomorrow morning before
another chance for showers and thunderstorms makes a comeback for
tomorrow afternoon and evening. These showers and storms look to be
mainly across southwest Minnesota. They could drift towards KFSD but
confidence is not high enough to include in KFSD`s TAF at this time.
Any showers and storms that do develop will wane through tomorrow
evening to end the TAF period.

&&

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

&&

$$

UPDATE...Meyers
DISCUSSION...AJP
AVIATION...Meyers