346
FXUS63 KFSD 100912
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
412 AM CDT Sat Oct 10 2026

.KEY MESSAGES...

- Near-Record Heat and Strong Winds Today: High temperatures may
  approach record levels alongside strong southwest winds of
  35-45 mph today. Highest winds along the Buffalo Ridge.

- Elevated Fire Danger and Blowing Dust: Today`s hot, dry, and
  windy conditions will lead to elevated fire danger and blowing
  dust potential. Farmers and travelers should be aware of
  localized visibility and air quality reductions and increased
  fire risks.

- Sharp Temperature Drop: A cold front arriving late Sunday will
  push temperatures downwards into early next week, closer to
  seasonal normals.

- Mid-Week Rain and Turning Colder: Expect dry seasonable
  weather through Tuesday before a stronger storm arrives
  Wednesday. A 60-70% probability of rain is already in the
  forecast by late Wednesday/Wednesday night with a potential
  shift to much colder temperatures next weekend.

&&

.UPDATE...
Issued at 410 AM CDT Sat Oct 10 2026

A very mild & breezy early October night with 3 AM temperatures
holding in the mid 60s to lower 70s over most of the forecast
area. This is aided by southerly winds occasionally gusting
20-30 mph, strongest along/downstream of the Buffalo Ridge.
Other than nighttime temperatures holding a bit higher than
forecast in response to the gusty winds, short-term forecast
remains on track early this morning as we move into a very warm,
windy and dry day ahead. Still looking at potential for south to
southwest winds gusting 30-40 mph across much of the area today,
with occasional gusts 40-45+ mph for portions of the Coteau des
Prairies/Buffalo Ridge in east-central South Dakota/southwest
Minnesota.

While these strong winds and low afternoon humidity levels will
push the Grassland Fire Danger Index into the High category for
most locations today, coordinated with neighbors in issuing a
Special Weather Statement (SPS) to highlight the elevated fire
weather concerns in areas where gusts over 40 mph could be more
prevalent. MPCA also highlighted southwest MN in an Air Quality
Alert today due to the potential for blowing dust pushing the
air quality index into the Orange, or Unhealthy for Sensitive
Groups category.

Still some uncertainties in timing of the mid-week system which
should bring increased rain chances and much cooler temperatures
to the region for the latter half of the week ahead. Latest
models generally focus higher rain chances moving into the
Missouri River Valley as early as Wednesday afternoon, with
highest chances Wednesday night into Thursday. However, there
are still some significant timing and evolution differences in
how quickly the strong southwest US low swings northeast and
phases with a strong northern stream wave, leading to lower
confidence in rain chances and temperatures through the latter
part of this forecast period.

&&

.DISCUSSION...
Issued at 1211 PM CDT Fri Oct 9 2026

THIS AFTERNOON: A rather pleasant day across the region as a weak
stationary boundary is beginning to drift northward. Weak
convergence along this boundary will keep a narrow corridor of mid
and upper 50 dewpoints drifting northward. Elsewhere, as afternoon
mixing and heating take over, we should see dew points mix downwards
slightly.

TONIGHT: A beautiful evening can be expected through the region as
high level cirrus pushes southeast.  Winds will stay light and mixy
through the night as the aforementioned front lifts northeast. While
some valley areas may cool into the 50s, the prevailing overnight
low temperatures will stay in the lower 60s in many areas, only a
few degrees off typical seasonal high temperatures.

SATURDAY: Near to record high temperatures will arrive for Saturday,
accompanied by gusty southwesterly winds and plenty of dry air.
The strong surface pressure gradient already pushing 15 to 20
mph sustained winds by mid-morning will continue to tighten
through the afternoon, but the deepening mixing will promote
mix down of the 40+ knot LLJ that will persist into the mid-
late afternoon hours. In these situations historically, deeper
mixing models will verify better for dew points and winds, so
have mixed both the HRRR/RAP into the forecast through the
afternoon hours. This will promote occasional wind gusts of 35
to 45 mph (highest along the Buffalo Ridge), and dew points
dropping into the lower 50s. While the NBM has started to catch-
up to recent warm temperature bias, making the mean population a
bit more reasonable, have again bumped up temperatures slightly
towards the 90th percentile given synoptic potential. This will
place high temperatures near daily records. One thing to watch
for Saturday will be the potential for harvest related blowing
dust, which could produce some very localized visibility and AQI
reductions. The combination of heat, wind, and drying fuels
will lead to elevated fire danger. Please see separate
discussion for further details.

SUNDAY:  Winds will weaken Saturday night as a frontal boundary
begins to approach from the west. However continued mixing after a
very warm afternoon will keep overnight low temperatures in the 60s.
This front will bisect the CWA by the middle of the afternoon,
promoting another day of highs in the 80s along and southeast of the
boundary, but a quick drop towards the 60s towards central South
Dakota.  There will be a sharp increase in mid-lvl clouds along the
boundary which may impact heating slightly. The front slowly settles
southeast into Monday morning, pulling cooler air into the James
River Valley. That said, there`s high potential that we`ll set new
record warm minimum temperatures Saturday and potentially again
Sunday.

MONDAY-WEDNESDAY:  Broad ridging over the Central CONUS and the
remnants of Hurricane Isaias will prevent any meaningful moisture to
be able to advect into the Tri-State area behind the passage of the
surface trough Monday morning. The end result may be an increase in
mid-lvl clouds and occasional virga/sprinkles in the afternoon.
Canadian high pressure slides southeast through the middle of the
week, keeping a dry forecast going, and dropping high temperatures
closer to their seasonal normals for a few days.

THURSDAY-FRIDAY: A bit of uncertainty develops in the extended
portions of the forecast as medium range models develop a deep
upper trough over the western CONUS. By Wednesday, there seems
to be consensus in both ensemble and AI based guidance that the
energy at the base of the trough begins to eject in to the
Plains. The increasing northward moisture return combined with
lift from the opening wave supports high PoPs from the NBM at
this time. EC/GEFS probabilities for >0.10" of QPF over 24 hours
is already over 60% through the region. While it`s still a bit
out there, the passage of this trough and eventual deepening of
a larger longwave trough through central North America could
signal at least a temporary shift towards colder than normal
temperatures into next weekend.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1102 PM CDT Fri Oct 9 2026

The low level jet will continue to impact the TAF sites through
the mid morning Saturday. VFR conditions to prevail through the
period. Will have to watch for any impacts from blowing dust
especially over southwest Minnesota where the strongest wind gusts
are expected, as this could cause some localized visibility
reductions at times. Not enough confidence in this potential at the
TAF sites, so opted to leave out any mention in those.

Winds will generally be out of the south through the period,
gusting to 30-35 kts for most areas near and east of the James
River during the daytime Saturday. The strongest winds will be
over the Buffalo Ridge where a few gusts could push 40 kts.
Surface gusts will diminish Saturday evening, but it will remain
breezy with sustained winds around 13-18 kts. LLWS concerns
will also return to areas mainly near and east of I-29 by the
end of the period.

&&

.FIRE WEATHER...
Issued at 410 AM CDT Sat Oct 10 2026

Concerns remain focused on fire weather today with little change
to the going forecast for wind gusts and humidity levels. South
winds could increase quickly by mid-late morning, with peak gusts
30-40 mph for most locations between 10 am and 3-4 pm. Locally
higher gusts near 45 mph will be possible along/near the Buffalo
Ridge in southwest Minnesota at times. Wind speeds may be on a
downward trend as we reach the lowest humidity levels of 25-35%
mid-late afternoon. This is more likely toward south-central
South Dakota where gusts ease to less than 30 mph as humidity
falls to near 20 percent.

The primary aspect of the GFDI that is keeping levels in the
"High" category in most areas is the relative percent greenness
of fine fuels. Recent rainfall and warm temperatures have led to
a slight increase in percent greenness and continues to hold
back higher end fire danger. However, we`re also now in the
heart of harvest season with crops significantly dry in many
areas. This is where the greater concern is today, as field
activities may be a driving force behind any wildfire potential.
The GFDI for fully cured fuels suggests considerable concern
through the Tri-State area, so extreme caution should be used
when working outside today.

&&

.CLIMATE...
Issued at 410 AM CDT Sat Oct 10 2026

Record High Temperatures:

October 10: KFSD: 88/1928 KSUX: 92/1928 KHON: 92/1928 KMHE: 93/1928
October 11: KFSD: 90/2015 KSUX: 91/2015 KHON: 91/1910 KMHE: 95/1910

Record High Minimum Temperatures:

October 10: KFSD: 64/1928 KSUX: 66/1930 KHON: 60/1947
October 11: KFSD: 67/1997 KSUX: 66/1997 KHON: 68/1997

&&

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

&&

$$

UPDATE...JH
DISCUSSION...Dux
AVIATION...Samet
FIRE WEATHER...Dux/JH
CLIMATE...Dux/JH