120
FXUS63 KBIS 272315
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
615 PM CDT Thu Mar 27 2025

.KEY MESSAGES...

- There is a medium to high chance (~50 to 80 percent) for light
  freezing rain across northwest and north central North Dakota
  late tonight through mid-afternoon Friday. Accumulations to a
  few hundreths of an inch expected.

- Temperatures will transition to below normal for the weekend,
  with highs in the upper 20s to upper 30s.

- There are medium chances for at least 2 inches of snow over
  southwest North Dakota Saturday into Sunday.

- Gradual warming trend through the upcoming week.

&&

.UPDATE...
Issued at 549 PM CDT Thu Mar 27 2025

Strong south to southeast winds continue over western and
central North Dakota early this evening. Do expect winds to
begin to drop off in the 6-7 PM CDT timeframe, to around 10-15
with gusts to around 20 mph through much of the evening. For the
most part, think we should remain dry this evening. There are a
few showers over northeast Montana, think most of anything
falling is virga, but there could be some sprinkles or a brief
shower. It`s possible we could see winds shift more west to
southwest if these showers make it into northwest ND. Will need
to monitor. Only some minor adjustments to sky cover and we did
raise winds over northwest ND through into early this evening.

&&

.DISCUSSION...
Issued at 154 PM CDT Thu Mar 27 2025

Current surface analysis places low over east-central Montana
with ridge over northern Manitoba into western Ontario. Upper
level analysis places ridge through the central and northern
plains, with low off the Pacific Northwest coast. Over our area,
winds have become quite gusty in the pressure gradient between
the two noted surface features, with the strongest wind gusts
around 40 mph over western parts of North Dakota. Otherwise,
rather quiet weather continues with some passing clouds mainly
over northern portions of the area with a short wave sliding
through the ridge over the southern Prairie Provinces.

For tonight, aforementioned surface low will shift
east-southeasterly towards western South Dakota overnight as a
variety of weak waves slide through the upper flow. Warmer air
aloft pushes north towards the Canadian border though surface
temps drop below freezing. Before the surface cooling, rain
chances spread over much of northwest and north central North
Dakota, but as surface temperatures cool, over far northern
areas first spreading south, chances switch towards freezing
rain and increase, with chances for freezing rain spreading
through much of the northern half of our area by morning. As we
go through later in the morning into the mid day hours, mid-
level temperatures cool with a switchover towards snow, while
southern areas remain rain. The concern is the what time this
switchover really occurs. With that all said, a Winter Weather
Advisory remains in places for our northern two tier of
counties. System will gradually depart late Friday afternoon
into Friday night before the next system enters the southwest
late.

Saturday will see the coolest temperatures during the forecast
period, as troughing aloft digs south through the Great Plains along
with surface high pressure building south into the Dakotas. Well to
our south, a surface low pressure system will develop, along with an
expansive precipitation field, the northern periphery of which may
make its way into our area beginning Saturday morning. Additionally,
a weak shortwave passing through the flow across the northern half
of the state may also bring about some weak precipitation across the
northern half of the state. Given the colder temperatures, this will
be falling as snow, but with only modest synoptic forcing and
limited moisture, this should all generally be light snow, with
accumulations ranging from 1 to 2 inches in the southwest, to just a
dusting in the north. In the far southwest, current NBM
probabilities for exceeding 2 inches of snow are right around the 40
to 50 percent range, with theses probabilities dropping off
substantially when it comes to 4 inches or more. There may be a
brief period during the late morning and afternoon hours where
temperatures may warm enough to bring about more of a rain/freezing
rain/snow mix in the southwest, though this will be pretty limited
in duration. High temperatures will stay mostly at or just below
freezing for a majority of the area, with portions of the far
southwest and far south central potentially rising to around 35
degrees.

This light precipitation is expected to continue into Sunday,
departing around mid-day. Cooler temperatures will continue on
Sunday, where highs will mostly be around freezing once more. From
Sunday onwards, messy flow aloft is expected to continue, resulting
in a bit more of an active pattern, albeit one that also sees a
gradual warming trend. Occasional 500 mb shortwaves will bring some
glancing shots of light precipitation, while a more substantial
trough is expected to dig south through South Dakota and Nebraska on
Tuesday and Wednesday, resulting in a more organized precipitation
event. Wraparound moisture from a surface low moving through South
Dakota will bring about a mix of light snow and rain during the day,
switching over to mostly light snow overnight. Once again,
accumulations at this time don`t appear to be too impressive, with
the highest amounts around an inch in the southern James River
Valley. With regards to temperature, a gradual warming trend is
expected across the entire area through this period. By Tuesday,
highs will generally range from the upper 30s in the northeast and
Turtle Mountains, to around 50 in the southwest. These temperatures
increase further, reaching into the 40s and upper 50s by Thursday.
While this warming trend is forecast to continue, NBM temperature
spreads from Thursday onward begins to get quite large, but looking
at some longer range models, zonal flow aloft and continued ridging
to our west will help keep these temperatures on the warmer end of
things. The same can be said with the somewhat active precipitation
pattern; while exact details on position and strength of shortwaves
moving the flow are still fuzzy, we may continue to see these weak
disturbances moving through the area through the extended period.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 549 PM CDT Thu Mar 27 2025

Gusty south-southeast winds are expected to diminish early this
evening. Late tonight into Friday morning, MVFR to IFR ceilings
will gradually spread from north to south and into eastern North
Dakota, with the exception being the southwest and south central
North Dakota. KDIK and KBIS may see MVFR ceilings hold off just
to the north, however, at this time will add a period of
afternoon MVFR ceilings. Rain chances spread over the area,
with freezing rain likely over much of northern North Dakota,
affecting the KMOT and possibly the KXWA terminals. As the
day goes on, there may be a transition towards snow around
midday at KXWA and KMOT, with any precipitation remaining liquid
at the southern TAF sites. Winds shift from southeast to more
northeast tonight and then remain north to northeast through
the day Saturday, generally 10 to 20 mph in the morning and 15
to 25 mph in the afternoon.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 1 AM to 4 PM CDT Friday for
NDZ001>005-009>013.

&&

$$

UPDATE...TWH
DISCUSSION...Besson/JJS
AVIATION...TWH