859
FXUS63 KFSD 180446
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1046 PM CST Tue Feb 17 2026

.KEY MESSAGES...

- Isolated strong to severe thunderstorms can`t be ruled out
  this evening, especially east of I-29. 60 mph wind gusts will
  be the threat, though widespread strong to severe storms are
  not expected.

- Winds increase tonight into tomorrow morning, gusting up to 50
  mph at times especially north of I-90 and into portions of
  northwest Iowa. This will also lead to fire weather concerns
  especially along and south of I-90 where relative humidity
  values will be lowest.

- The potential for light accumulating snow returns Thursday
  into Thursday night. The best chance for at least an inch of
  snow (40-60%) is south of I-90 at this time. A narrow band of
  2-4+" inches may set up over parts of our area, though
  uncertainty in the placement of this heavier band remains
  high.

&&

.UPDATE...
Issued at 1040 PM CST Tue Feb 17 2026

Taking across the area, a band of light rain continues to lift
northwards this evening with the surface low leaving very light
accumulations (<0.10") in its wake. As its associated cold front
quickly follows this system, we`re continuing to see an uptick in
winds speeds with numerous observations across the Black Hills
and Red River showing wind gusts in the 45-55 mph range with
isolated pockets of up to 70 mph. With a strong push of cold air
advection (CAA) and shallow mixing expected overnight, the
current expectation is for a burst of stronger winds to progress
through the area overnight with gusts between 45-55 mph
expected and a few isolated pockets of higher possible. With
this in mind, decided to expand our current wind advisory
southwards towards the Missouri River Valley since short-range
guidance continues to hint at more widespread coverage. From
here, expect the gusty conditions to persist at least through
the first half of the day before gradually by late afternoon.

Shifting gears to our fire weather concerns, everything keeps
pointing towards a higher end fire weather set up given the
conditions. Mild temperatures along with gusty westerly winds and
lower RHs values (15%-30%) will lead to very high to extreme fire
danger by Tuesday afternoon with focus being along and south of I-
90. With this in mind, decided to upgrade our Fire Weather Watch to
a Red Flag Warning for the previously mentioned areas valid from 10
am to 6pm. With all this in mind, make sure to limit any activity
that could create a spark as fire would quickly spread out of
control with these conditions.

&&

.DISCUSSION...
Issued at 240 PM CST Tue Feb 17 2026

One last very warm February day out there, with temperatures having
climbed mainly into the 60s. It`s been a breezy day too, and
these winds will diminish this evening, at least for a few
hours. A cold front will be moving through the area this evening
as well and will help provide some lift for showers to develop.
These showers will actually some elevated instability to work
with, and thus a few thunderstorms cannot be ruled out. Can`t
entirely rule out an isolated severe storm as there will be
ample dry air beneath these elevated storms. This would mean
gusts potentially as high as 60 mph, but widespread strong to
severe storms are not expected. Synoptic winds will increase
through tonight as strong cold air advection pushes into the
area behind the cold front, with gusts up to 50 mph expected.
This will be the case especially for areas north of I-90 where
the Wind Advisory has been expanded to include the rest of
southwest Minnesota north of I-90. These stronger winds will
spread into northwest Iowa heading into tomorrow morning, but
the current thinking is the chances for these stronger wind
gusts in excess of 45 mph will only last an hour or two, so did
not expand the advisory at this time and will be captured by the
Fire Weather Watch. More on that in the fire weather discussion
later on.

Some wrap-around precipitation may impact mainly the Highway-14
corridor late tonight into tomorrow morning. This will likely start
as light to very rain, turn to light to very light snow, and then
back to rain before exiting. Not expecting any snow with this to
accumulate, but there could be very brief reductions in
visibility in any light snow due to the stronger winds that
will be in place during the morning commute tomorrow.
Temperatures turn cooler heading into the day tomorrow behind
the aforementioned cold front, with highs mainly in the 40s and
50s. Of course, this is still above normal, but it only gets
colder from here.

Heading into Wednesday night and Thursday, a surface low will move
across the central Plains, with most guidance then pulling the
system northeastward to the Great Lakes by Thursday night/Friday.
17.12z guidance has continued to show the southerly trend of the low
through the central Plains as shown in the 17.06z guidance, and this
has lead to the latest NBM pulling the 2+ inch snow amounts farther
south and east closer to a Sioux City, IA to Jackson, MN line.
Looking at the 17.12z ensembles, there appears to be less of a
noticeable southerly trend as some of the deterministic models, so
it`s entirely possible the next suite of deterministic guidance
starts to pull the snow farther north again. All that to say, still
a lot of uncertainty in exact amounts, but even with light snow,
reductions in visibility will be possible due to breezy conditions.
As of now and based on the current forecasted track of the system,
most spots south of I-90 look to see a moderate (40-60%) chance of
snow of at least one inch of snow. There may be a narrow stripe of 2-
4+" of snow depending on where the heaviest band of snow moves
through. This would be favoring areas closer to the Highway-20
corridor at this time, but again uncertainty remains high on where
this band sets up, so be sure to keep up to date with the latest
forecast. Chances of greater than 4 inches of snow remains low
(<20%), but can`t be completely ruled out.

For timing, look for some light snow to start to move into the
Missouri River Valley by Thursday morning, with snow chances
gradually lifting northeastward through the afternoon and evening.
Snow should exit from northwest Iowa and adjacent southwest
Minnesota Thursday night. Not much time to look into the long-range
forecast, but temperatures do look to be colder heading into the
weekend. Highs return mainly to the 20s and 30s with lows down in to
single digits, though temperatures could trend colder or warmer
depending on how much snow falls.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1040 PM CST Tue Feb 17 2026

Mostly VFR conditions will continue this TAF period. Besides a
few patchy hours of LLWS mainly in KSUX, areas of light showers
will continue to lift northwards overnight giving way to more
clear conditions. Otherwise, gusty westerly winds will continue
for most of the TAF period.

&&

.FIRE WEATHER...
Issued at 240 PM CST Tue Feb 17 2026

Winds will be stronger heading into the day on Wednesday, gusting in
excess of 40 mph at times especially during the morning hours and
especially north of Highway-18. Relative humidity values will be
dropping to critical levels in the afternoon, especially along and
south of I-90. So even though winds will be slowly diminishing
through the afternoon hours, there is enough overlap especially
along and south of I-90 to warrant issuing a Fire Weather Watch 11
am to 6 pm tomorrow. Wind direction should primarily be out of the
west through the day tomorrow. Fire weather conditions will diminish
on Thursday and through the weekend as snow chances and colder
temperatures make a return.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Red Flag Warning from 10 AM to 6 PM CST Wednesday for SDZ050-
     057>071.
     Wind Advisory until noon CST Wednesday for SDZ038>040-053>056-
     059>062-065>071.
     Wind Advisory until noon CST Wednesday for SDZ050-052-057-058-
     063-064.
MN...Wind Advisory from 2 AM to noon CST Wednesday for MNZ071-072-
     080-081-089-090-097-098.
     Red Flag Warning from 10 AM to 6 PM CST Wednesday for MNZ089-
     090-098.
IA...Wind Advisory from 2 AM to noon CST Wednesday for IAZ001>003-
     012>014-020>022-031-032.
     Red Flag Warning from 10 AM to 6 PM CST Wednesday for
     IAZ001>003-012>014-020>022-031-032.
NE...Red Flag Warning from 10 AM to 6 PM CST Wednesday for NEZ013-
     014.
     Wind Advisory until noon CST Wednesday for NEZ013-014.

&&

$$

UPDATE...05
DISCUSSION...Samet
AVIATION...05
FIRE WEATHER...Samet