717
FXUS63 KBIS 101015
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
415 AM CST Wed Dec 10 2025

.KEY MESSAGES...

- Another round accumulating snow is expected late this
  afternoon through Thursday night. Areas of freezing rain are
  also possible across the west and south central through
  late Thursday morning.

- Below average temperatures are expected today through the
  upcoming weekend, with dangerous wind chills possible Thursday
  evening through Sunday morning.

- More accumulating snow is possible across the west and south
  central Friday through early Saturday.

&&

.DISCUSSION...
Issued at 415 AM CST Wed Dec 10 2025

Northwesterly flow is found over the northern Plains this
morning. Light wintry precipitation lingers over north central
North Dakota into the northern James River Valley, trailing
along and behind a inverted surface trough associated with the
clipper system that passed through North Dakota yesterday. A
transient upper level ridge is expected to move through the
northwesterly flow pattern this morning through much of the day,
and will allow high pressure at the surface to move into the
northwest. While this will help further erode precipitation and
the somewhat gusty northwest winds that lingered overnight.
Before that time light, non accumulating snow will remain
possible over portions of north central North Dakota into the
northern James River Valley through this morning. Clearing
conditions are then anticipated through the late morning and
afternoon as high pressure slides across North Dakota. Low
temperatures this morning are from the lower single digits below
north, to the upper single digits to mid teens above south.
High temperatures this afternoon are forecast from the upper
single digits to mid teens central, to the lower 20s to lower
30s west.

Another round of impactful winter weather is expected early
this evening through Thursday as another upper level wave passes
through the northern Plains. Chances for precipitation will
increase as strong 850-700mb WAA pushes in across the west,
accompanied by decent FG forcing. At the fore of this system,
periods of moderate to heavy snowfall will be possible across
the west this evening through early tonight as the
aforementioned FG forcing aligns with decent Q vector
convergence. Then, in a similar setup to Tuesday, a ongoing WAA
will cause a deep warm nose aloft, allowing for a switchover
from snow to freezing rain across the west and south central
overnight through late Thursday morning. During this transition,
portions of southwestern and south central North Dakota may
experience precipitation in the form of ice pellets, as the
initially elevated nature of the warm nose aloft could allow for
refreezing of falling liquid before it reaches the surface.
CAMs remain somewhat discordant on the exact cessation time of
the freezing rain, mainly due to differences in when the warm
nose aloft erodes. A good majority of the CAMs favor an initial
weak slug of CAA moving in out of the northwest mid to late
Thursday morning, which will allow for a slightly quicker
change-over to all rain and snow across the forecast area. A
minority of CAMs instead favor WAA continuing through the late
morning, early afternoon period which would allow freezing rain
to continue across south central North Dakota for a little
longer. In either scenario, the cold front associated with the
low pressure system is then expected to move in out of the
northwest, and facilitate a complete conversion to snow through
the remainder of Thursday. As of the current forecast cycle, NBM
5.0 Calibrate probabilities has medium to high chances (50 to
80 percent) for at least 0.001" of ice accumulation across much
of western and portions of central North Dakota, with
probability dropping off quickly north of Highway 200. Chances
for 0.10" are generally low (10 to 20 percent) across much of
the same area, though a small area of medium (30 to 40 percent)
can be found in south central North Dakota, mainly along and
east of the Missouri River and south of I-94. This area would
have the greatest residence time for freezing rain overall, not
to mention the scenario where it lingers into the early
afternoon mentioned above. With banding potential Wednesday
afternoon and evening, and with the freezing rain overnight
through Thursday morning, A Winter Weather Advisory is in effect
across western North Dakota start 3 PM CST Wednesday, then
expanded to include portions of central North Dakota starting 6
PM CST Wednesday, through 6 PM CST Thursday. With this update,
we have opted to start the Advisory a little earlier across the
west due to potential for moderate snowfall to start late
Wednesday afternoon.

After the cessation of freezing rain, lightly accumulating snow
is then expected to continue across much of western and central
North Dakota from the remainder of Thursday afternoon through
late Thursday night, perpetuated by an incoming arctic cold
front Thursday evening. When all is said and done, much of
western and central North Dakota has medium to high (30 to 60
percent) probabilities to exceed 1.0 inches of snow through
Friday morning, with low to medium probabilities to exceed 2.0
inches overall.

The aforementioned arctic cold front will bring much colder
temperatures and gusty winds starting Thursday night through
Friday, and addition to the light snowfall through Friday
morning. Low temperatures Friday morning are forecast from the
mid teens below zero north, to around zero south. With these
temps, with northwesterly winds with speeds from 15 to 20 MPH
and gusts up to 30 MPH overnight, there are medium to high
chances (50 to 80 percent) for dangerously cold wind chills
below -30 across the northern portions of the forecast area
Friday morning, mainly north of Highway 200 plus the northern
James River Valley. That being said, a slightly faster
progression of the cold front overnight could allow for this
potential area to spread further to the south. High temperatures
Friday morning are also very cold, with much of northwest and
central North Dakota unlikely to rise above freezing. Saturday,
if anything, will be even cooler across the north, though less
windy than Friday. Low temperatures Saturday and Sunday morning
are broadly forecast as low as -20 in north central North
Dakota, up to around -5 in the southwest and south central.
Despite the lack of winds, there are again medium to high for
portions of northern North Dakota to experience dangerously cold
wind chills both mornings, with the highest potential north
central. High temperatures on Saturday are from -10 north
central, to around 10 above southwest, then warming into lower
teens east to lower 30s southwest on Sunday. Persistant
northwesterly flow will allow for more opportunities for
precpitation essentially each day over the weekend, though
Friday through Saturday is currently looking like our best bet
at the moment. Another low pressure system passing to the
southwest of the forecast area will allow for medium to high
chances (50 to 80 percent) for accumulating snowfall west and
south central. NBM calibrated probabilities for at least 2
inches of snow through Saturday morning are high south and west
of the river, with low to medium chances to exceed 4 inches in
the far southwest for the same period. Looking ahead to next
week, the warming trend starting Sunday is to continues, with
forecast highs broadly back into the 30s and 40s by Tuesday.
CIPS analogues lean toward near to above normal temperatures to
continue through the end of the workweek.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 415 AM CST Wed Dec 10 2025

Light falling and blowing snow can be found across central
North Dakota to start the 06Z TAF period. Visibilities where
this is occurring have dropped into MVFR to IFR criteria.
Precpitation will slowly exit to the east over the next few
hours, generally out of the forecast area by 09Z. With this
update, have added light SN and BLSN to KJMS. MVFR ceilings and
visibility lingers over much of the forecast area this time
though is similarly diminishing from west to east, with KXWA
already improving to VFR ceilings at the time of this update.
Ceilings generally improve to VFR conditions by mid Wednesday
morning. Another period of wintry precpitation is expected late
Wednesday afternoon through the end of the TAF period,
accompanied by MVFR ceilings and visibilities as light snow is
followed by freezing rain. Ice accumulation from 0.001 to 0.10
of an inch is expected across portions of western and south
central North Dakota through Thursday morning, with snow
accumulations from 1 to 3 inches possible during this same
period. MVFR ceilings are expected to expand across the forecast
area, reaching all terminals except KJMS by the end of the TAF
period.

Moderate to strong northwest winds persist across the forecast
area at this time, with speeds up to 35 MPH and gusts up to 45
MPH observed in the southwest and south central, including the
southern James River Valley. Winds will to diminish overnight,
becoming light and somewhat variable late Wednesday morning and
afternoon. By Wednesday evening, a general reorganization out of
the south southeast is anticipated, along with a general
strengthening to speeds up to 15 MPH and gusts up to 25 MPH
through the end the TAF period.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 3 PM CST /2 PM MST/ this
afternoon to 6 PM CST /5 PM MST/ Thursday for NDZ009-017-018-
031>033-040-041-043-044.
Winter Weather Advisory from 6 PM CST /5 PM MST/ this evening
to 6 PM CST /5 PM MST/ Thursday for NDZ010-019>021-034-035-042-
045-046.

&&

$$

DISCUSSION...Adam
AVIATION...Adam