656
FXUS63 KBIS 122305
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
605 PM CDT Sun Oct 12 2025

.KEY MESSAGES...

- Very windy through this evening, with west to northwest winds
  around 30 to 35 mph and gusts as high as 55 mph.

- Periods of rain expected in northwest North Dakota this
  afternoon through mid evening. Snow could briefly mix in with
  the rain during the early evening.

- Widespread below freezing temperatures expected across
  northern and western North Dakota tonight. Widespread freezing
  temperatures are possible across the north again Monday night.

- Much cooler to start the work week, then warming back up to
  near or slightly above average mid to late week.

- Medium to high chances for rain Wednesday through Friday.

&&

.UPDATE...
Issued at 548 PM CDT Sun Oct 12 2025

Latest surface obs and radar loop shows strong winds across
western and central ND late this Sunday afternoon. Thin band of
reflectivities with maybe some light rain is currently tracking
through the James River Valley. Another area of precipitation
is situated over northeast Montana into northwest ND. This area
looks to linger over northwest ND a bit longer, so adjusted pops
here to linger into mid evening. The Williston ASOS did report
snow for a while this hour. Webcam near Fortuna also looked to
show some snow. Can`t rule out some light snow here through mid
evening at times, but with little or no accumulation expected.

No changes to the current Hazards. Did have a couple gusts to 67
mph during the 4 PM hour in southwest ND.

&&

.DISCUSSION...
Issued at 245 PM CDT Sun Oct 12 2025

We have a little bit of everything across western and central
North Dakota through the forecast period. Today, a potent upper
level trough is cutting across our northwest into the southern
Canadian Prairies through the late afternoon and evening. With a
deepening surface low associated with this feature analyzed at
the surface, a strong pressure gradient, a large amount of CAA,
and a well mixed boundary layer is present across the northern
Plains this afternoon, inducing strong west winds with speeds up
to 30 MPH and gusts up to 50 MPH across much of the forecast
area. While the strongest winds across our southern counties are
anticipated this afternoon, a majority of deterministic models
(60~70 percent) favor the development of a LLJ wrapping around
the upper level trough as it closes off through the early
evening. With this in mind, winds across the north may remain
linger, with speeds up to 30 MPH and gusts up to 50-55 MPH
through the late evening. Thus a Wind Advisory is in effect
across much of the forecast area, excluding the James River
Valley, through 8 PM CDT / 7 PM MDT, and then across just the
counties north of the Missouri River and Highway 200 through 12
AM CDT.

Regarding precipitation today, there are two areas of interest.
The first is a thin band of precipitation moving across south
central North Dakota into the James River Valley this afternoon
and evening, mainly associated with a vort max ejecting off of
the upper level low. Precipitation here is anticipated to be
relatively light and spotty, with only a low chance (10 to 20
percent) for any given location to see rain. Then, in the
northwest, the broad deformation zone wrapping around the low is
anticipated to induce widespread medium to high (60 to 90
percent) chances for precipitation through this afternoon and
evening. The majority of measurable rainfall across the forecast
area is anticipated to be here, with probabilities of at least
0.25" (one quarter inch) of measurable precipitation broadly
from 30 to 60 percent. Notably, with a much cooler airmass
settling over the region on the backside of the cold front, the
far northwest could see a little bit of snow become mixed in
with the rain this afternoon through the evening. That being
said the ensemble has backed off significantly on the snow
potential over the past few forecast cycles, only advertising a
low (10 to 20 percent) chance for measurable snow at most. With
such a slight amount falling mainly falling onto warm surfaces
during the afternoon period, it is unlikely that any
accumulation will occur during this period.

Otherwise, for today, much cooler temperatures are on the
docket in the post frontal environment found across much of the
state. With a cold front having passed through much of the
forecast area, temperatures in western and much of central
North Dakota already peaked in the 50s and 60s earlier this
morning. Slightly warmer temperatures, in the 60s and 70s, were
found in the South James River Valley this afternoon where
compressional heating and skies remained slightly clear this
morning, but temperatures here too have already begun to fall on
the backside of the cold front. With a weak surface trough
moving in behind the cold front, and high pressure bleeding in
across the west from Alberta by the way of eastern Montana, low
temperatures tonight are anticipated to drop to or below
freezing across much of the forecast area tonight. Portions of
the southern James River Valley may struggle to reach freezing
temperatures as west to northwesterly winds are anticipated to
remain somewhat elevated overnight, but it is not impossible.
With this in mind, low temperatures tonight are forecast broadly
in the mid to upper 20s west, and in the lower 30s central. A
Freeze Warning is in effect for most of western and central
North Dakota from 8 PM CDT / 7 PM MDT this evening through 10 AM
CDT / 9 AM MDT Monday morning, excluding the James River
Valley.

Cooler and drier conditions are then on the docket as a
transient upper level ridge peaks across the northern Plains on
Monday, with highs on peaking into the 40s to lower 50s across
the forecast area. With surface high pressure settling at the
surface, skies are anticipated to be mostly sunny to partly
cloudy. Another cold night is then anticipated, especially
across the north where light winds will allow temperatures to
again dip down to around or below freezing.

Looking ahead to Tuesday, the squashing of the transient ridge
will set southwesterly flow over the region. Shortwave impulses
ejecting off a deepening ridge over the western CONUS will then
slide across this flow, allowing for increasing cloud cover and
low to medium chances for rain (20 to 50 percent) late Monday
night through early Tuesday afternoon. Otherwise for Tuesday,
highs in the 40s to lower 50s persist across the forecast area.

Moving ahead into the middle of the week, a slight warming of
temperatures back into the 50s and 60s is anticipated as a
slightly more aggressive upper level ridge builds up across the
Great Plains ahead of the aforementioned western CONUS trough.
The ensemble becomes somewhat discordant during this period as
the timing of this upper level trough, progged to close off
into an upper level low as it cross the Rockies, comes into
question. A plurality of model members (approximately 45 percent
of model members) favor a faster, deeper low center. This
scenario would be the wetter of the two, with portions of
northwestern North Dakota approaching 1 inch of rainfall total
through the end of the workweek. This cluster seems to be the
one the ensemble as a whole is advertising, with widespread
medium to high chances (60 to 90 percent) of precipitation
starting late Wednesday through late Friday. A smaller cluster
also exists (approximately 35 percent of model members), which
champions a slower low that begins to open up by the end of the
workweek. This scenario would be the drier of the two, with the
highest rainfall totals in the northwest struggling to exceed
one half inch by the end of the workweek as rainfall would not
start until late Thursday morning. Notably GEPS model members
were not available for this clustering period, which accounts
for the missing 20 percent. In either scenario, our next
opportunity for widespread precipitation is anticipated to be
through the second half of the coming workweek. Luckily with the
warming temperatures, all precipitation is anticipated to fall
as rain, with little to no chance of snow currently expected
during this period.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 548 PM CDT Sun Oct 12 2025

MVFR ceilings across northern ND this evening including KXWA and
KMOT. A brief IFR ceiling is also possible here as well. Over
central and southern ND, low VFR to occasional MVFR ceilings
this evening. Currently all of the southern TAF sites are low
VFR, but a period of MVFR ceilings can not be ruled out at these
sites this evening, especially at KDIK. MVFR visibilities are
possible across northern ND this evening, with an IFR vsby
possible if precip changes to snow. Highest probabilities for
lower vsbys will be mainly along the International border, but
can not be completely ruled out at KMOT or especially KXWA.

Strong west to northwest winds will gradually diminish this
evening in the south, but will remain strong across the north
through the evening.

Winds will diminish and ceilings lift after midnight, especially
for central and southern ND. MVFR ceilings could linger through
the night and into Monday morning across northern ND. Currently
VFR conditions are expected through the day Monday at all TAF
sites.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until midnight CDT tonight for NDZ001>005-
009>013-021>023-025.
Freeze Warning until 10 AM CDT /9 AM MDT/ Monday for
NDZ001>005-009>013-017>023-031>036-040>047-050.
Wind Advisory until 8 PM CDT /7 PM MDT/ this evening for
NDZ017>020-031>037-040>047-050.

&&

$$

UPDATE...TWH
DISCUSSION...Adam
AVIATION...TWH