Harrisburg, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

556
FXUS63 KFSD 251132
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
632 AM CDT Wed Mar 25 2026

.KEY MESSAGES...

- Near record heat possible today for some locations with highs
  in the 70s and 80s.

- Fire Weather remains the primary concern over the next
  several days with very dry fuels, warm and breezy conditions,
  and little to no precipitation.

- Elevated to critical fire weather conditions are most likely
  Thursday and Saturday onward, although each day poses some
  threat.

- No impactful weather systems expected through the weekend, but
  temperatures remain quite variable. Probabilities for more
  than 0.10" of rain remain around or less than 10%, with these
  probabilities focused north of US Highway 14 and south of US
  Highway 20.

&&

.UPDATE...
Issued at 302 AM CDT Wed Mar 25 2026

Only minor changes to the forecast over the next 24 hours.
Temperatures early this morning remain on track, falling into the
30s and 40s. Clouds continue to stream over the area with southerly
winds. For later today, main change was to increase winds and gusts
slightly across south central SD, pushing gusts closer to 20-25 mph
(20 knots). This doesn`t look to have too much impact on fire
danger, keeping things in the High category out there, but wanted to
better reflect some of the higher trends and potential. That said,
caution should still be used to prevent fire start with very low
humidity (less than 30% most places) which may lead to fires
spreading quickly. Warming into the 70s and 80s keeps us in near to
record breaking territory for Huron (80 set in 1908), Sioux Falls
(82 set in 1910) and Sioux City (80 set in 1925).

Changes come tonight with a cold front moving through the area.
Temperatures on Thursday will be cooler; however, main concern is
the timing of the strongest winds. We`ll see the first push of
stronger winds up to 40 mph as the initial front and CAA aloft move
through the area in the morning to early afternoon. Higher res
guidance is bringing some localized gusts to 45 mph or higher.
Additionally, HRRR and RAP guidance bring another push of strong
winds to the area late Thursday into early Friday with a secondary
front aloft. Timing of these winds is certainly something to keep an
eye on, as although RH values will be higher and temperatures
cooler, stronger winds will likely push fire conditions much closer
to critical.

&&

.DISCUSSION...
Issued at 118 PM CDT Tue Mar 24 2026

Mild and dry air surges north in the low levels tonight and will set
up a very mild day Wednesday. This will lead to mild overnight lows
tonight, generally mid 30s to lower 40s with highs on Wednesday in
the 70s with a few 80s south of I-90.

A system swings by to the north Wednesday night and should only
bring some cloud cover to the area Wednesday night into Thursday.
Some very weak elevated instability near highway 14 may allow for a
few showers late Wednesday night, but amounts would be very light.
Also some very weak elevated instability near northeast NE into
parts of northwest IA that could lead to a few showers. Currently
instability is too weak, but if enough can sneak in around KSUX we
could see some gusty winds with any showers that could develop with
a fairly unidirectional wind and deep/dry sub cloud layer.
Otherwise, the main effects from this wave will be a cold front that
will dive south Thursday afternoon. Ahead of this front a very mild
air mass will be in place with Thursday morning lows in the 40s to
lower 50s. The initial front will sag south on Thursday morning and
the secondary stronger front in the afternoon. Wind gusts likely 30
to 40 mph.

Friday should be mostly sunny with stable northwest flow in place.
Temperatures cool quite a bit behind the exiting system, so looking
at highs in the 40s and 50s.

Mainly westerly flow stays in place this weekend into early next
week, setting the stage for warm temperatures and very little chance
for precipitation. The models are hinting at a slightly stronger
wave Tuesday night into Wednesday next week, but far enough out not
too concerned or confident, but something to keep an eye on.
Otherwise looking at highs in the 60s on Saturday and 70s Sunday
into Tuesday.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 628 AM CDT Wed Mar 25 2026

VFR conditions through the forecast period, with mid and high
clouds. Winds will be light and somewhat variable through the
day today, with some gusts around 20 knots in south central SD.
Expect an increase in winds through the overnight hours
tonight into Thursday as a cold front swings through the area.
Gusts by daybreak Thursday around 25-30+ knots from KMJQ to
KFSD to KYKN. Direction shifts to northerly behind the front.
May see some directional LLWS toward the last few hours of the
period as the front moves through, but have omitted for now
given marginal speed shear and fropa timing differences.

&&

.FIRE WEATHER...
Issued at 302 AM CDT Wed Mar 25 2026

Well above average temperatures and and low dew points lead to RH
values less than 30% for most of the area later today. However,
winds and gusts remain less than 25 mph for locations outside of
south central SD. Lighter winds temper widespread elevated to near
critical fire danger today falling into the Moderate to High
category. However, if we mix more than anticipated and winds are
stronger, more widespread concerns are possible.

Winds increase and turn northerly tonight with gusts by daybreak
around 40+ mph as a cold front moves through the region. Guidance is
still split on how quickly this front moves through and how
prolonged strong winds last, which will have a significant impact on
fire danger and behavior. There may also be a secondary push of
stronger winds late Thursday into early Friday behind a trailing
front, but guidance is even more split on this potential. Despite
cooler temperatures and higher humidity, near critical to possibly
critical fire danger is expected - especially if the front moves
through a bit slower.

Conditions remain cooler but breezy Friday. RH values once again
fall below 30% for nearly all of the area, so elevated to near
critical conditions expected once again.

Warming temperatures this weekend will drop RH values below
critical thresholds both days. Both days look to be breezy, with
the strongest southerly winds on Saturday (gusts to 35 mph
possible). Sunday does look warmer and drier with slightly weaker
winds than Saturday. More of the same into early next week. So
overall, critical conditions look to be most likely from Saturday
into early next week.

Little to no precipitation is expected through the weekend, with low
confidence in precipitation chances into the middle of next
week.

&&

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

&&

$$

UPDATE...SG
DISCUSSION...08
AVIATION...SG
FIRE WEATHER...SG