397
FXUS63 KBIS 171034
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
434 AM CST Mon Nov 17 2025

.KEY MESSAGES...

- On and off low to medium chances for light rain today through
  Wednesday night, with a 20 percent chance of light freezing
  rain in north central North Dakota tonight.

- Near to above normal temperatures this week, with highs each
  day mostly in the upper 30s to lower 50s.

- Colder temperatures and above normal precipitation are favored
  for the last week of November.

&&

.DISCUSSION...
Issued at 434 AM CST Mon Nov 17 2025

An upper level ridge axis extends from southern Saskatchewan to
the Ark-La-Tex region early this morning. A closed mid/upper
low spinning from Utah into Wyoming is forecast to move eastward
through the day, traveling along the South Dakota/Nebraska
border this evening. The placement of western and central North
Dakota under the influence of the northeast quadrant of the low
through this afternoon could provide enough lift from isentropic
ascent, warm air advection, and deformation zone dynamics to
produce pockets of light rain. Early attempts at this have
already been noted on radar imagery over southwest North Dakota,
but it will likely take awhile for the lower part of the column
to saturate enough for anything to reach the surface. While we
are confident that there will be light rain across some parts of
western and south central North Dakota today, the point-
specific probability of measurable rain is only around 20 to 30
percent. The axis of the highest rain chances is roughly from
around New Town to Jamestown. A mostly cloudy day is
anticipated, with forecast highs in the upper 30s to mid 40s.
Today is also expected to be the breeziest day of the week, with
east- southeast winds around 15 to 20 mph and isolated
afternoon gusts near 30 mph.

Synoptic scale forcing is forecast to wane through tonight,
which should lead to a gradual diminishing of the light rain.
Any precipitation that holds on into the late night hours will
be susceptible to changing over to light freezing rain as
surface temperatures fall near freezing. The highest probability
for a light glaze of ice is in north central North Dakota where
a couple of CAMs are actually simulating a higher spatial
coverage and intensity of freezing rain, but it is still only a
20 percent chance at most when considering the entire NWP suite.
Ensemble thermal profiles appear too warm to support any snow
as a precipitation type tonight.

The Turtle Mountains area could see some light (freezing) rain
early Tuesday morning as a shortwave passing through central
Canada induces warm air advection. Tuesday is otherwise looking
to be a drier and slightly warmer day as a transitory upper
ridge pivots through the region, ushering in a period of
southwest flow aloft Tuesday night into Wednesday. High-
resolution guidance that extends into Tuesday night is bullish
on an area of light rain crossing the state, with higher chances
south compared to north. Global ensembles also project a 20 to
40 percent chance of measurable precipitation across our south
Tuesday night, but the NBM has these probabilities much lower,
which may be due to the influence of older model cycles. We
compromised at a 15 to 20 percent chance of light rain for now,
but think these chances will trend higher barring any major
model shifts. Forecast lows Tuesday night are around 30 to 35,
but we are confident in above freezing temperatures while it is
raining. Snow once again appears to not be a plausible type
Tuesday night on account of warm temperatures aloft. Some of the
Tuesday night rain could linger into Wednesday morning as flow
aloft turns zonal ahead of a series of northern stream
shortwaves in a split flow regime that is now forecast to have
the southern wave stall over the Desert Southwest. There is
still a 20 to 30 percent chance of light precipitation Wednesday
night as the highest amplitude wave in the northern stream
drags a weak cold front across the region, but this is looking
less impressive compared to previous forecast iterations. This
would also be likely to fall as rain across most of the state,
but with potential for a transition to a wintry mix along the
international border before ending.

The passage of the cold front Wednesday night should yield a
slight cooldown for Thursday, but with highs still near to above
average in the mid 30s to mid 40s. Ensemble clusters and
deterministic models then offer a variety of solutions on the
evolution of the synoptic pattern heading into the weekend, but
there seems to be a slight favoring of a northwest or zonal flow
that could contain intermittent periods of low-amplitude
ridging and troughing. Although there is a noticeable increase
in ensemble spread beginning Friday, temperatures are favored to
remain near to above normal through the weekend. The NBM
temperature distributions then take a distinct trend cooler
leading up to Thanksgiving, and this coincides with deep central
CONUS troughing depicted in long-range mean ensemble height
fields.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 434 AM CST Mon Nov 17 2025

VFR conditions are likely to prevail through the forecast
period. Light rain could develop across southern and possibly
northwestern North Dakota this morning and afternoon. Aviation
impacts are not expected at this time, though a period of MVFR
visibility cannot be completely ruled out under the rain.
Ceilings should remain at VFR levels. East-southeast winds will
increase to around 15 kts this afternoon, with a few higher
gusts possible.

&&

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

&&

$$

DISCUSSION...Hollan
AVIATION...Hollan