779
FXUS63 KBIS 180526
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1126 PM CST Wed Dec 17 2025

.KEY MESSAGES...

- Damaging westerly winds will be found tonight through
  Thursday. Most of North Dakota will see wind gusts of 60 to 80
  mph, with far southwestern portions of North Dakota expected
  to see wind gusts of 80 to 90 mph with some locally higher
  gusts possible.

- Snow fall tonight through Thursday morning will generally
  range from 1 to 4 inches across western and central North
  Dakota. Blizzard conditions are expected across the north and
  east.

- Areas not in a Blizzard Warning, could still see near blizzard
  conditions in falling snow. Snow squalls are also possible in
  these same areas later this evening into the early overnight
  hours.

- Dangerous wind chills will be found in the north Thursday
  morning.

- Warming temperatures, breezy winds, patchy blowing snow, and
  low to medium chances (20 to 60%) for a wintry mix will be
  found on Friday.

&&

.UPDATE...
Issued at 1123 PM CST Wed Dec 17 2025

Updated AFD for updated aviation section below.

UPDATE
Issued at 953 PM CST Wed Dec 17 2025

Snow squall parameters earlier again shifted west and southwest,
but still are grazing my far southwest for another hour or two,
then are projected south and out of our area for the remainder
of tonight. There was one lightning strike northwest of Glendive
a couple hours ago, but none since. Wrap around snow associated
with strong wrap around CAA over eastern Montana and
occasionally over southwest North Dakota continues to surge
southeast. CAMs doing a decent job showing this, and reflected
POPs based on latest imagery, trends, and CAM output. Winds have
just started to really ramp up across the southwest over the
past hour, with numerous gusts over 58 mph and several to
around 70 mph. Winds will only keep increasing over the next
several hours as the strong CAA surges south and east across the
local area. Still potential for higher end gusts in excess of 80
mph southwest as has been and still is occurring across
Montana.

No changes to headlines.


UPDATE
Issued at 610 PM CST Wed Dec 17 2025

The main changes to the forecast were to slow down the eastward
progression of rain showers based on latest radar imagery and
CAMs, along with delaying the arrival of strong winds west to
east a bit.

Surface analysis drapes a sfc trough/frontal boundary from
southern Saskatchewan east-southeast into north central North
Dakota, then south across south central ND into central South
Dakota. West of this boundary, western North Dakota has ramped
up winds, with gusts at 1800 CST up to around 55 mph. Expect
these winds to spread east as the FROPA pushes east, and
especially increasing as strong CAA surges east-southeast into
the state in a few hours, increasing lapse rates and the mixing
layer, allowing the stronger winds aloft to mix to the surface.
Northwest ND may see a break for a few hours later this evening
as the aforementioned boundary sags southward from Canada, but
will pick back up again around/after midnight behind this
boundary. Main pressure rise surge is also still depicted to
spread southeast across the state around 06Z through around 12Z,
so strong winds will continue through the night.

Regarding snow squall potential, latest RAP and SPC mesoanalysis
has shifted the higher potential west, still grazing my far
southwest. Timing would be around to after 03Z this evening.
There is indeed an enhanced area of radar returns over north
central/northeast Montana (just now moving through the Glasgow
area), with this activity moving south-southeast with the CAA
surge. It`ll be a few hours until this gets close to the MT/ND
border, and will continue to monitor this activity. With the
current trajectory, it does indeed appear just my southwest will
be under the gun this evening regarding snow squall potential,
but time will tell.

&&

.DISCUSSION...
Issued at 314 PM CST Wed Dec 17 2025

A strong and elongated surface low currently on the border of
southern Alberta and Saskatchewan is hovering around 974 mb.
Ahead of this low is a weak warm front bringing some weak
returns on the radar, although dry air is limited the rain that
is reaching the surface. Regardless this chance of rain will
push eastward the rest of this afternoon into the early evening.
Behind these rain showers, strong westerly winds will start to
increase. Although the strongest winds sill remain in Montana,
this initial push of wind could still approach High Wind Warning
Criteria. Thus left the High Wind Warning as is for start times.

After sunset until around midnight, there could be a brief
period of dry conditions while we wait for the cold front to
push through. By mid to late evening an initial front moves
through. Along this will be chances for light snow, and snow
squalls. The snow squall parameter remains high and generally
south and west of the Missouri River. Those traveling in these
areas tonight will need to stay alert for snow squalls, which
can bring brief blizzard conditions with little notice. From
around 9 pm to 3 am CT will see the strongest winds as the very
strong pressure rises on the back side of this very strong low
pressure system move through. 850 mb winds are forecast to be in
excess of 50 knots for most areas, with 700 mb winds in excess
of 90 knots across the southwest. This is important to note
because these will be the potential winds that could mix down to
the surface tonight. Thus the potential range of wind gusts are
60 to 100+ mph. This will greatly depend on the low level lapse
rates, which are the best in the southwest. Forecast soundings
in these areas showing 80+ knots may mix down, which could bring
gusts to 90 mph. These kind of winds are usually reserved for
higher end severe thunderstorms. Although different types of
systems, the impacts from tonights strong winds could be
similar. On the backside of this low later this evening through
tonight will be widespread light snow, with perhaps some slight
enhancement in the north. Snowfall of 1 to 4 inches combined
with the strong winds will bring near blizzard to blizzard
conditions. Areas with the highest confidence in blizzard
conditions are now in a Blizzard Warning. Areas just short of
this high confidence mark now have a Winter Weather Advisory
for impactful blowing snow. On top of all that, cold arctic air
will move in behind this front. Dangerous wind chills are
expected in the north, with a Cold Weather Advisory now in
effect for Thursday across these areas. Lows tonight will drop
into the single digits above and below zero.

A much colder day is then in store for Thursday, with snow,
blowing snow, and strong winds ending from west to east. East of
Highway 83 could see strong winds and blowing snow impacts
linger through the day, while west of Highway 83 sees impacts
diminish as early as late Thursday morning. High temperatures
for most areas will be in the single digits and teens. Cold
temperatures return Thursday night, with lows from the teens
below zero northeast to the teens above zero southwest. Light
winds may become a breezy southerly wind through the night,
perhaps bringing some dangerous winds chills again, although
temperatures are expected to start warming ahead of the next
clipper system late Thursday night or early Thursday morning.
Forecast track for the next clipper system on Friday may take a
more northerly track, with precipitation along the warm front of
this system. NBM has mainly snow as a precip type in today`s
forecast, although a mix of rain and freezing rain will also be
possible given the potential warming conditions. Winds could be
breezy to windy through the day Friday, with patchy blowing snow
to any areas with blowable snow, mainly in the north. Highs will
be in the 20s west to 40s east. Winds then go westerly Friday
night with perhaps some lingering snow and blowing snow chances.
Cold temperatures will return with lows near zero north to the
teens south. Perhaps some dangerous wind chills may also return.

Zonal flow then looks to take over this weekend into early next
week. At times this could lead to weak ridging or weak
troughing. Moist pacific air may hold together long enough to
bring brief chances for showers as well. NBM spreads are high
during this period given the uncertainty on when the pattern is
more ridge like versus trough like. Some days could see highs
and lows above normal, while others are near to slightly below
normal. This pattern does not favor strong winds. NBM pop
chances are also currently low (20% or less) although this could
change if more of a trough pattern develops.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1123 PM CST Wed Dec 17 2025

Snow developing from west to east will combine with strong
winds and bring periods of LIFR and IFR across most sites with
snow and blowing snow. Blizzard conditions are expected from
KXWA to KMOT to KRUG to KJMS with this system, and are briefly
possible elsewhere. Conditions then improve from west to east
later Thursday morning through Thursday afternoon, with VFR
conditions returning to all terminals for the remainder of the
06Z period, except those with lingering blowing snow. Strong
westerly winds will be found with this system. Most sites will
see gusts over 50 knots, with southwestern sites perhaps seeing
gusts over 65 knots. Strong winds may also bring periods of low
level wind shear to most sites at times, possibly through the
night.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Blizzard Warning until noon CST /11 AM MST/ Thursday for
NDZ001>003-009>011-017-021.
Cold Weather Advisory from 6 AM to noon CST Thursday for
NDZ001>003-009>011.
Blizzard Warning until 6 PM CST Thursday for NDZ004-005-012-
013-022-023-025-037.
Cold Weather Advisory from 6 AM to 3 PM CST Thursday for
NDZ004-005-012-013.
High Wind Warning until noon CST /11 AM MST/ Thursday for
NDZ009-017-018-031>033-040-041-043-044.
Winter Weather Advisory until noon CST /11 AM MST/ Thursday
for NDZ018>020-031>034-040>045.
High Wind Warning until 3 PM CST /2 PM MST/ Thursday for
NDZ019>021-034>036-042-045>048-050-051.
Winter Weather Advisory until 6 PM CST Thursday for NDZ035-036-
046>048-050-051.

&&

$$

UPDATE...NH
DISCUSSION...Anglin
AVIATION...NH