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Every 3 hours, broken out across temperature, snow, rain, humidity, and wind. Each cell is colour-coded relative to the column min/max.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
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Forecast discussion
What forecasters are seeing
Plain-English forecast narrative from the local NWS office. Issued by NWS FSD.
595
FXUS63 KFSD 230820
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
320 AM CDT Fri Oct 23 2026
.KEY MESSAGES...
- Elevated Fire Danger Friday: Warm temperatures in the 70s and
80s combined with wind gusts up to 45 mph will create near-
critical fire danger Friday. Avoid outdoor burning or
activities that create sparks such as fall harvest activity
may want to consider postponing.
- Breezy with Scattered Showers Friday Morning: Scattered rain
showers (20-45% chance) and very isolated thunderstorms
develop after 3 AM, with activity lifting northeast through
the morning hours. Not everyone will see rain.
- Cooling Down This Weekend: A cold front will move into the
area on Saturday, bringing light, spotty rain and dropping
afternoon highs into the 60s for the western half of the
region.
- Soaking Rain and Chilly Air Next Week: Expect a major weather
shift Sunday night through Tuesday. Widespread, persistent
rain will arrive with many areas receiving between a half-
inch and nearly one and a half inches, alongside a sharp cool-
down into the 40s and 50s.
&&
.UPDATE...
Issued at 319 AM CDT Fri Oct 23 2026
A layer of moisture from about 8-12 kft will move through early this
morning as a weak wave moves through. With some minor amounts of
instability above this layer of moisture, scattered showers will
develop early this morning and likely exit the area to the
northeast from mid to late morning. Amounts will be light, but
some smaller pockets of a tenth of an inch will be possible.
Elevated to near-critical fire weather conditions remain likely
today as temperatures climb and winds increase, likely gusting to 35
to 45 mph throughout the day. The one negative factor regarding
rapid fire spread will be a minimum afternoon relative humidity
around 40 percent, a little high for rapid spread. Model soundings
are also hinting at some mid and high cloud cover lingering into the
afternoon which will be a minor limiting factor to fire spread and
could keep highs a touch lower than expected.
After today attention turns to an extended period of cooler
temperatures with periods of rainfall. An upper level jet will move
northeast through the Western High Plains Saturday into Sunday,
bringing a series of weak waves to the area. Saturday will likely
see scattered showers with isolated thunderstorms. Elevated CAPE
values climb to about 300-400 J/kg in the morning through early
afternoon. Periodic saturation aloft and weak instability
continue into Sunday, so isolated to scattered showers remain
possible.
The better chance for rainfall will come Sunday night into Monday as
the upper level jet only slowly shifts eastward and the area remains
entrenched in the right entrance region of the upper level jet. This
will allow low to mid level frontal forcing to increase and deeper
saturation to increase as well. This will be the focus for the best
chance for widespread rainfall. The latest GEFS and EC Ensemble are
indicating a 70-100 percent chance for a half an inch of rain,
especially in southeast SD. The chances for more than an inch of
rain is sitting at about 50-80 percent in the same area.
&&
.DISCUSSION...
Issued at 124 PM CDT Thu Oct 22 2026
THIS AFTERNOON: Another beautiful afternoon across the Tri-
State area as temperatures continue to rise into the 70s. As the
SPG continues to increase surface winds are beginning to gust
over 20 to 25 mph at times, highest along and west of the James
River valley. Mid- lvl clouds associated with a broad increase
in 600:500 mb RH will continue to spread northeast, through have
been thinning. Fire danger remains high in most areas west of
I-29 so caution should be used in farm fields into the evening.
TONIGHT: Winds will remain breezy through the overnight hours,
keeping overnight lows much warmer than normal. After midnight,
we`ll begin to see the breakout of mid-lvl clouds as warm
advection within the 700:600 mb range increases. Short term CAMs
are coming into more consensus in the development of scattered
high based showers after 3am, which may increase further by
12-15Z as lift maximizes on the increased LLJ moving into SW
Minnesota. While a very low chance, MUCAPE in the effective
layer rises up to 200-300 J/KG indicating at least isolated
lightning potential. Will increase POTThunder to account for the
risks.
FRIDAY: Any morning shower and isolated storm activity will
lift into west central and central Minnesota by mid-day.
Troughing entering the Central Rockies will further intensify
the SPG through the day, with sustained winds of 15 to 20 mph
developing by mid-day. Despite the SE surface flow, we`re likely
to see gusts increase towards the 35 to 45 mph range by mid-day
with these gusts continuing into the very early evening hours.
Temperatures may be a bit more uncertain Friday afternoon,
somewhat dependent on lingering mid- lvl cloud cover. The
warmest reading are still expected along and west of the James
River where upper 70s to lower 80s may be possible. Greater
temperature spreads remain over SW Minnesota where highs could
range anywhere from the lower 70s with clouds to the upper 70s.
Warm temperatures and strong winds will lead to elevated to near
critical fire danger. Please see separate discussion on fire
weather risks.
SATURDAY: A frontal boundary that remained over western South
Dakota Friday will begin to advance eastward overnight reaching
into the western half of the CWA by daybreak Saturday. Mid-lvl
vorticity streaming NE along this frontal zone may lead to
scattered high bases showers to sprinkles through the day on
Saturday. Soundings show ceiling bases only as low as 8K ft AGL
by Saturday afternoon, with a fair amount of dry air still
infiltrating the sub-cloud layer in the afternoon. This should
help keep any QPF on the low side and rain more sporadic. The
front and clouds could have a profound impact on afternoon
temperatures, with some guidance suggesting highs near 60 well
behind the front, with highs closer to 75 in areas near Sioux
City to Storm Lake and Spencer more displaced from the boundary.
This light rain opportunity will continue through Saturday
night into Sunday morning as the surface and low-lvl boundary
remains stalled overhead.
SUNDAY-WEDNESDAY: A bit more uncertainty develops on Sunday,
focused around the positioning of the surface front. Models like
the NAM, that tend to be overly strong on cold air surges
southeast, push the front all the way towards central Iowa. The
ECMWF on the other hand increases mid-lvl ridging through the
Central Plains and slows the arrival of upper troughing over the
Central and Southern Rockies. This in return forces the
boundary further northwest. The GFS splits the two solutions,
keeping the boundary nearby and focusing more clouds and
occasional spits of rain through the heart of the CWA. Never
mind the solution, there may be brief lull in rainfall on Sunday
with most guidance suggesting any rain chances diminish during
the the first two thirds of the daytime hours.
Those rain chances increase once again Sunday night and
continue through Monday as the upper trough over the Rockies
begins to eject into the Plains. Increasing mid-lvl warm
advection will assist in developing a narrow low-lvl frontal
zone near the Tri-State area that should drive more persistent
rain chances. More direct lift from the upper wave itself
arrives late Monday into Monday night, though there remains
considerable uncertainty on the track of the upper wave.
Needless to say, probabilistic data continues to indicate high
rain chances through the region, but indicate quite a spread on
potential rainfall totals. Standard 25/75th QPF ranges from the
NBM suggest anywhere from 0.50"-1.75" for most of the CWA, with
probabilities for >1.0" greater than 60% still focused along and
west of the James River and into the Missouri River valley.
In addition to the rain, another more direct impact from this
upcoming system will be a sharp drop in temperatures early next
week. While blended guidance and ensemble guidance suggests
highs in the lower to middle 50s given the existing model
spread, individual members suggest potential for much colder
temperatures (40s) under the core of heavier precipitation
Monday and Tuesday.
&&
.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1058 PM CDT Thu Oct 22 2026
Scattered showers will develop around sunrise, with low
potential for thunder. Some of the heavier showers could bring brief
MVFR visibilities and mix down some wind gusts approaching 40 kts,
but this will be an exception to the norm. Showers will develop near
the Missouri River Valley and lift northeastward through the morning
hours Friday. Southeasterly surface winds and a south-southwesterly
low level jet could cause brief directional low level wind shear
concerns through daybreak, but confidence was not high enough in the
coverage and longevity of this to include in the TAFs at this time.
Wind will be the main story through the period, with southeasterly
winds expected to gust to around 35 kts at times mainly near and
west of I-29 by the late morning into the afternoon. Locally higher
gusts to 40 kts can`t be ruled out mainly in south-central South
Dakota and along the higher elevations of the Coteau des Prairies.
This could blow some dust from any nearby agricultural activity, so
there`s a potential for brief and localized visibility drops
with this as well.
&&
.FIRE WEATHER...
Issued at 124 PM CDT Thu Oct 22 2026
Concerning fire weather develops on Friday. After morning
sprinkles to light rain move northeast, strong southeast surface
winds develop through the day with sustained winds to 20 mph
and gust of 35+ mph. Greater wind focus will develop west of
I-29, but especially along and west of the James River valley
with occasional gusts to 45 mph are likely. While temperatures
reach near 80 degrees, dew points may try to pool ahead of a
weak front in central South Dakota. This may hold relative
humidity values well above critical red flag warning thresholds.
However, a special weather statement and other messaging will
be considered for this unique scenario.
That said, the combination of strong winds, drying fuels, and
abnormally warm temperatures will lead to widespread high to
very high GFDI values (along and west of I-29). The greater
danger will be in harvest activities, with the GFDIAg values
reaching well into the very high category over most of the CWA.
Any agricultural activities should use caution and local
partners should be aware of the increased potential for fire
starts in farm fields.
Light rain begins to move into the area by Saturday, with
chances increasing for a widespread wetting rain into early next
week.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
UPDATE...08
DISCUSSION...Dux
AVIATION...Samet
FIRE WEATHER...Dux