403 
FXUS63 KBIS 051524
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
924 AM CST Fri Dec 5 2025

.KEY MESSAGES...

- Areas of freezing drizzle and light snow across southwest and
  south central North Dakota this morning.

- Near daily chances for light snow through Tuesday.

- High confidence in 1 to 2 inches of snow along and to the
  south and west of the Missouri River tonight through Saturday,
  with locally higher amounts up to 4 inches in southwest parts
  of the state.

- A more impactful system could bring strong winds along with
  both rain and snow (medium to high chances) across the region
  Monday night through Tuesday night.

- Near average temperatures today, below average this weekend,
  above average Monday and Tuesday, then below average favored
  again the second half of next week.

&&

.UPDATE...
Issued at 913 AM CST Fri Dec 5 2025

Precipitation is exiting the southern portion of the state
attim. Temperatures mainly in the 20s with some teens north
central and lower 30s far southwest. Once precip exits the south
it should be mostly dry through the rest of the day until precip
arrives again from the north and west later on.

UPDATE
Issued at 650 AM CST Fri Dec 5 2025

Surface observations and webcams continue to indicate widespread
mixed precipitation across the southern half of our forecast
area early this morning. Only a few tenths of an inch of snow
have been reported across western and south central parts of the
state since late last evening, but it was a wet and slippery
snow and there is now increasing concern in a thin layer of ice
coating over it. Observed, analysis, and forecast soundings are
atypical for freezing drizzle, so there is low confidence on how
long this threat will continue and how impactful it may become.
A Special Weather Statement has been issued to cover this
hazard, and the gridded forecast has been updated accordingly.

&&

.DISCUSSION...
Issued at 509 AM CST Fri Dec 5 2025

Synopsis: A persistent northwest flow pattern over the Northern 
Plains will bring a parade of clippers across the region through 
next week. Ensembles are fairly consistent in the timing and 
placement of each system through Tuesday, with notable differences 
among ensemble clusters emerging thereafter. This pattern results in 
a forecast that contains repeated chances for snow (with mixed 
precipitation at times), wildly varying temperatures, and periods of 
breezy, if not windy conditions.

Today: Surface low pressure is analyzed over southeast North Dakota 
early this morning, with the parent mid level trough dropping into 
western North Dakota. Snow has not been nearly as widespread as 
anticipated during the overnight hours, and some automated 
observations continue to indicate mixed phase hydrometeors, 
including freezing drizzle. Areas of light precipitation are likely 
to continue along and ahead of the southward surging cold front 
attendant to the surface low this morning, which has already reached 
from around Williston to Fargo. There could also be a separate area 
of flurries crossing northern parts of the state later this morning 
from weak DCVA. Most of the precipitation should exit or diminish by 
the afternoon, but there are two exceptions. One is the potential 
for light lake effect snow to the south-southeast of Lake Sakakawea 
as low level temperatures cool below -10 C in a north-northwest flow 
over the lake. This would particularly favor locations downwind of 
the Van Hook Arm from northwest to central Mercer County for a 
period of lake effect snow with light accumulations possible. There 
could also be some light snow along a baroclinic zone in southwest 
North Dakota this afternoon, with no accumulation expected. 
Otherwise, expect near steady to falling temperatures around 20 
degrees north to 30 degrees southwest this afternoon as another 
surge of Arctic air approaches from southern Canada. Breezy 
conditions are also expected this afternoon.

Tonight-Saturday night: The next wave is forecast to bring 
accumulating snow to western and south central parts of the state 
late tonight through Saturday evening. There is uncertainty in the 
northward extent of the snow as it will be contending with a dry and 
cold northeasterly surface flow eminating from an Arctic high 
pressure over Saskatchewan that has a tangential ridge axis 
extending down through the northern Red River Valley. The highest 
snow accumulation probabilities are generally along and to the south 
and west of the Missouri River, with medium to high chances for at 
least 1 inch and low to medium chances for exceeding 2 inches per 
the experimental NBM version 5.0 (similar probabilities are 
exhibited by the HREF). There is a low potential for a smaller area 
of higher amounts (most likely high-end amounts around 4 inches) 
driven by transient low level frontogenesis coupled with strong Q-
vector convergence and a deep layer of steep lapse rates, but 
deterministic models are not in agreement whether these ingredients 
will simultaneously come to fruition in the same area. Aside from 
the snow, it will once again become colder tonight into Saturday, 
when daytime highs are only forecast to reach the single digits 
above zero north and east to near 20 in the southwest corner of the 
state. Most of the state is then forecast to see sub-zero lows 
Saturday night, but lighter winds should keep wind chills from 
falling colder than -20.

Sunday-Monday: A warm front is forecast to cross the region from 
west to east Sunday afternoon through Sunday night. The western half 
of the state could see around a 10 degree improvement in afternoon 
temperatures from Saturday to Sunday, while the eastern half 
struggles to rise out of the single digits. A band of light snow is 
also favored to accompany the warm front, with ensembles showing 
medium to high probabilities for measurable snow, but very low 
probabilities for exceeding 1 inch (less than 20 percent). Near-
steady or rising temperatures are forecast Sunday night, followed by 
highs on Monday rebounding to the mid 20s northeast to mid 30s 
southwest. The shortwave that is responsible for the Sunday warm 
front could bring some light snow to north central and eastern parts 
of the state on Monday. Western North Dakota could see windy 
conditions in the warm sector on Monday. The cold front attendant to 
this wave looks to be much weaker and is barely expected to impact 
temperatures. 

Monday night-Tuesday night: The warm front attendant to the next 
system is forecast arrive in western North Dakota as early as late 
Monday night. There is unusually high ensemble agreement given the 
time range and pattern that this clipper will be the strongest in 
this series, with a surface low forecast to cross the state from 
northwest to southeast during the day Tuesday. There are high 
probabilities for precipitation with this system, including a medium 
potential for at least 0.25" QPF from northwest to east central 
North Dakota. Precipitation types look to be an issue across western 
and south central North Dakota. There is high confidence that it 
will be warm enough both above and at the surface for precipitation 
to fall as rain over the aforementioned areas from late morning 
through the afternoon. What is less certain is whether the initial 
precpitation associated with the warm front will arrive early enough 
to fall through a warm layer aloft (high probabilities for 850 mb 
temperatures above freezing) onto surface temperatures that are 
still below freezing. Both deterministic and ensemble guidance hint 
at this potential, but there is not enough consistency to begin 
widely advertising an icing threat at this time. Accumulating snow 
also seems very likely with this system to the north and east of the 
Missouri River, but climatologically low snow ratios render the 
threshold probabilities of 0.25" QPF equivalent to those for around 
1 to 2 inches of snow. Finally, deterministic guidance and the 
conceptual model suggest this system could produce very strong 
winds, and there is a shift-of-tails showing up in the ECMWF EFI 
wind gusts fields, indicating a low probability of high-impact wind 
event. 

As mentioned in the opening paragraph, there is far less certainty 
and greater ensemble spread beginning mid next week, despite 
confidence remaining high in the synoptic northwest flow pattern 
continuing. The NBM maintains a 20 to 30 percent chance of snow 
through Thursday, and despite large 25th-75th percentile ranges, 
there is a distinct shift colder in the NBM maximum and minimum 
temperature distributions.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 555 AM CST Fri Dec 5 2025

Light snow and patchy freezing drizzle remain possible across 
southwest and south central North Dakota early this morning, but
chances diminish from north to south by early afternoon. Low 
ceilings are expected to prevail through this afternoon, with 
LIFR to MVFR heights early this morning transitioning to just 
MVFR this afternoon. Southwest North Dakota could maintain a low
ceiling through tonight, including falling back to IFR. MVFR 
ceilings are also forecast to expand back across the western 
half of the state by early Saturday morning. Another round of 
snow is expected to enter western North Dakota late tonight, but
may not reach the major terminals until near the end of this 
forecast period. Gusty northwesterly winds are expected later 
this morning through the afternoon, then becoming light and 
variable this evening into tonight, and easterly around 10 kts 
in western North Dakota later tonight.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...TWH
DISCUSSION...Hollan
AVIATION...Hollan