988
FXUS63 KBIS 151730
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1130 AM CST Sat Nov 15 2025

.KEY MESSAGES...

- Cooler and mostly dry this weekend, with a low to medium of
  chance of light rain in southwest North Dakota this afternoon
  and evening.

- Temperatures remain closer to average for the upcoming work
  week, with highs mostly in the mid 30s to mid 40s.

- Low to medium chances for light mixed precipitation Monday
  through Thursday. Little to no impacts expected at this time.

&&

.UPDATE...
Issued at 1130 AM CST Sat Nov 15 2025

The leading edge of precipitation associated with 700-850mb FG
forcing has begun to slide into southwestern North Dakota at
the time of this mid day update. Upstream observations in
eastern Montana have mainly been light rain so far, though
a station in north central Montana has begun to report light
snow as well. With this update, have tweaked PoP grids to
account for a slightly earlier start time of precipitation.
Otherwise, the forecast remains broadly on track at this time.

UPDATE
Issued at 945 AM CST Sat Nov 15 2025

Generally quiet weather is found over western and central North
Dakota at the time of this mid morning update. Low level clouds
over the southwest have generally lifted, though a mid level
cloud deck continues to spread eastward this morning. To the
west of the forecast area, another area of shallow clouds and
modest reflectivities have developed in eastern Montana,
associated with a mid level jet and a thin band of 700mb FG
forcing. Both these features are anticipated to spread eastward
into the forecast area through this afternoon and evening,
promoting scattered showers for western and portions of central
North Dakota during this period. With this update, have blended
in the latest CAMs into the PoPs forecast, and have tweaked
cloud cover to account for satellite trends. Other than this
minor adjustments, the forecast remains on track at this time.

UPDATE
Issued at 555 AM CST Sat Nov 15 2025

A small area of light rain showers persists in the Standing
Rock Reservation at the time of this writing, but should soon
shift fully into South Dakota or dissipate. Low to mid clouds
continue to be more prevalent than guidance had suggested, but
there are now at least some breaks in the clouds. No major
forecast changes are needed for this update, but did throw in a
patchy fog mention for the southwest late tonight into Sunday
morning. This does seem like a favorable setup for fog formation
from differential cooling along the western edge of a stratus
shield, with light surface winds and low level subsidence.

&&

.DISCUSSION...
Issued at 357 AM CST Sat Nov 15 2025

North Dakota is under a zonal flow pattern this morning,
sandwiched between an upper level ridge over the Southern
Plains and an upper level low crossing northern Manitoba. A
cold front has passed southward through the state, and a
surface high pressure is currently analyzed over southwest
Saskatchewan/northeast Montana, drifting southeastward. The mid
to upper level cyclonic flow has maintained a large swath of
low to mid clouds across much of the region that models are
struggling to pick up on, lending to low forecast confidence in
their evolution.

The general expectation is that flow aloft will turn
northwesterly today as the surface high slides through Dakotas,
which should clear out at least some of the clouds from the
north and east. Southwest North Dakota is more likely to remain
cloudy through the day though, and an embedded low amplitude
shortwave traveling along a baroclinic zone with modest low
level frontogenesis could produce a band of light rain across
southwest North Dakota this afternoon, possibly shifting into
south central North Dakota this evening before dissipating
overnight. This signal has been consistent in high- resolution
guidance for over 24 hours, but with varying placement and
intensity of simulated reflectivity. Nevertheless, the maximum
HREF QPF with this system is only around a tenth of an inch,
and the probability matched mean is only a few to several
hundredths of an inch. Some snow could mix in along the colder
(northeast) side of the band, but no accumulation is expected.
High temperatures today will be significantly cooler but still
near to slightly above average, ranging from around 40 north to
near 50 southwest.

The southeastward progression of the surface high pressure is
forecast to stall tonight into Sunday as a trough digs into the
Great Lakes region. Meanwhile, a potent wave over California
will begin to spin northeastward and force amplification of an
upper level ridge along the eastern slopes of the Rockies. The
transition to an anticyclonic flow pattern should keep Sunday
dry and allow a slight warmup, although a southeast surface wind
is not favorable for strong diurnal mixing of the boundary
layer. Forecast highs for Sunday range from around 40 northeast
to the lower 50s southwest. There is also a signal for fog
formation in models that simulate visibility across parts of
western and south central North Dakota early Sunday morning,
but there is not enough spatial and coverage consistency to add
this to the forecast at this time.

Much of the upcoming work week is forecast to feature a
predominant split southwest flow pattern over the Northern
Plains. This results in daily low to medium chances for
precipitation, but with high probabilities for only light QPF
(less than 0.10" daily) where precipitation occurs. Thermal
profiles do suggest mixed types, including a potential for
freezing rain/drizzle. It is difficult to have high confidence
in any particular aspect of the precipitation forecast in this
type of synoptic pattern, but there is an emerging signal for
southern North Dakota to be on the northern periphery of a
compact shortwave Monday night into Tuesday that could provide
enough low level warm air and moisture advection for a light
rain/drizzle event, with near-freezing surface temperatures.
There is also agreement in ensemble clusters for a more
progressive, but still split-flow shortwave crossing the central
CONUS late Wednesday into Thursday. Cluster analysis does
indicate the northern stream could cross the state, but the
probability of over a tenth of an inch of QPF with this system
is only around 20 to 30 percent. Overall, the general
expectation is for a cooler and cloudier work week with periods
of light precipitation. Little to no impacts from frozen
precipitation types are anticipated at this time, but will need
to monitor the Monday night/Tuesday morning timeframe for a
freezing drizzle potential. Deterministic NBM highs are in the
mid 30s to mid 40s, but there is a large spread in the daily
maximum distributions, and deterministic values are skewed to
the warmer side. This conflicts with the anticipation of
increased cloud cover, so would not be surprised to see the
high temperature forecast trend cooler as the time approaches.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1130 AM CST Sat Nov 15 2025

VFR ceiling and visibility is found at all terminals to begin
the 18Z TAF period. This afternoon and evening, scattered
precipitation slides across the west and south central as a mid
level jet slides from in from Montana, accompanied by MVFR
ceilings. Have added a PROB30 group for -RA for KDIK, where
confidence in precipitation is highest. While much of this
precipitation is expected to fall as rain, some light snow is
possible along the northern and eastern edge of the
precipitation axis. All precipitation is expected to diminish
and move out of the forecast area by the early overnight period.
Late tonight through Sunday morning, shallow patchy fog is
possible in the southwest. With this update, have a slight
visibility reduction to KDIK, though have maintained VFR
visibility. Otherwise, gusty northwest winds are found in the
James River Valley this afternoon, with speeds from 15 knots
gusting to 25 knots. Winds should lighten and become variable as
high pressure settles over the region overnight, organizing out
of the southeast through Sunday morning and the end of the TAF
period.

&&

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

&&

$$

UPDATE...Adam/Hollan
DISCUSSION...Hollan
AVIATION...Adam