914
FXUS63 KBIS 311720
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1220 PM CDT Sun Aug 31 2025

.KEY MESSAGES...

- Showers and thunderstorms expected today, mainly in western
  North Dakota. Chance for showers and thunderstorms returns on
  Labor Day, mainly in northern, central, and eastern portions.
  The probability for severe weather is low.

- Showers and thunderstorms may accompany passage of a cold
  front on Tuesday. The probability for severe weather is low.

- Cooler weather with highs in the 60s and 70s then anticipated
  mid to late week. Overnight lows in the 30s and 40s also
  forecast.

&&

.UPDATE...
Issued at 1220 PM CDT Sun Aug 31 2025

Visibilities across North Dakota have improved to 6 miles or
above at the time of this mid day update. Showers across the
west remain fairly isolated, though a most consistent band of
scattered showers is starting to move in from northwestern South
Dakota at this time. Have made some minor adjustments to the
sky grids at this time, but otherwise the forecast remains on
track.

UPDATE
Issued at 1000 AM CDT Sun Aug 31 2025

Visibility has begun to improve across central North Dakota at
the time of this morning update. That being said, fog is has
been much showers to lift over portions of the James River
Valley and east. Thus, while the Dense Fog Advisory will be
allowed to expired over much of the area, it has been extended
for Stutsman and Foster counties through noon. Otherwise,
showers continue over portions of southwestern North Dakota at
this time. Overall, other than the aforementioned fog extension
in the James River Valley, the forecast remains broadly on
track.

UPDATE Issued at 638 AM CDT Sun Aug 31 2025

Dense fog has formed across much of the advisory area this
morning. This is expected to linger into the mid to late morning
hours. Overall the dense fog is within the advisory area, with
some patchy fog possible elsewhere. Overall limited changes to
fog was needed at this update. The next round of showers may
start to push into the southwest later this morning. PoPs
overall remain on track thus have not made many adjustments.
Thus the forecast remains on track with limited updates needed
at this time.

&&

.DISCUSSION...
Issued at 407 AM CDT Sun Aug 31 2025

High pressure to the east will provide light winds and high RH
recoveries this morning to the eastern half of the state. As a
result areas of dense fog are anticipated through the mid to
late morning hours. Some sites are already reporting dense fog,
with other sites reporting at least some visibility
restrictions. As a result have issued a Dense Fog Advisory for
central and eastern portions with the highest confidence for
dense fog this morning. Elsewhere could at least see some patchy
fog. Meanwhile, lingering moisture in the west could continue
chances for showers through the morning. Fog is expected to
diminish mid to late this morning. Cut off low exits the region
today, although lingering moisture could still bring showers and
a few thunderstorms in the west today, is perhaps an isolated
thunderstorm central late this afternoon into this evening. The
lack of shear and lift should limit any severe weather threat.
High temperatures today may remain slightly cooler and generally
in the 70s south to lower 80s north. Tonight, lingering moisture
aloft remains in the area although limited lift should limit
precipitation chances. If some clearing skies can be found, then
fog could return tonight into Labor Day morning. Lows tonight
will generally be in the 50s to lower 60s. Weak short wave is
then forecast to move through on Labor Day, pushing some if this
lingering moisture eastward. Instability looks to be slightly
elevated during passage of this wave, and a weak jet streak
could bring some low to perhaps modest shear. Scattered
thunderstorm activity is possible as a result, especially in the
central and east. Perhaps an isolated stronger storm is possible
given the potential for modest instability. SPC currently has a
general thunderstorm risk for Labor Day. Slight warmer
temperatures may also be found Labor Day, with highs in the mid
70s to mid 80s. Afternoon humidity values may lower in the 20s
and 30s in the west. Light south winds today may change to a
light westerly wind on Labor Day after passage of this mentioned
wave. These light winds should limit any fire weather threat.
Precipitation activity moves east Monday night, with lows in the
50s. High RH recoveries could again be found Monday night,
although a steady wind may also be found. Perhaps some patchy
may still return.

Cold front still forecast to move through on Tuesday. Ahead of
it may still be near normal highs, with cooler highs behind it.
Breezy northerly winds may also be found behind this front.
Chances for showers and thunderstorms will also be found with
this front. Shear looks to increase on Tuesday, although
instability is somewhat lacking. Thus an isolated stronger
storm is possible, although the chance for severe weather
remains low. Chances for showers and thunderstorms could then
linger Tuesday night, with lows in the 40s to lower 50s. Post
frontal day could then be found on Wednesday with breezy and
cool conditions. Highs remain forecast in the 60s, with mainly
dry conditions also forecast. Cooler northwest flow may then
remain through the rest of the work week. NBM continues high
temperatures in the 60s and 70s, although spreads still remain
somewhat large. Morning lows Thursday and Friday morning are
forecast in the 40s, with perhaps some mid to upper 30s possible
Thursday morning. This may need to be monitored for any frost
concerns. North to northwest winds may also linger through the
end of the upcoming week. These could be breezy at times,
although a signal for strong winds is currently not present.
Mainly dry conditions are also currently forecast with this
northwest flow pattern. Perhaps a weak wave moves through at
times, although confidence is not high enough for PoPs at this
time.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 1220 PM CDT Sun Aug 31 2025

VFR ceilings and visibility is found at most terminals to begin
the 18Z TAF period. A lifting stratus deck lingers over the
James River Valley, and may keep MVFR to IFR ceilings at KJMS
through the early afternoon. Scattered showers are starting to
moving into southwestern North Dakota at the time of this
update, with chances spreading north and east through the
afternoon. A few isolated thunderstorms are possible with these
showers as well. Have added a PROB30 group of -SHRA at KDIK this
afternoon, with confidence being too low to include such mentions
at any other TAF site at this time. Tonight, another round of
fog is possible across much of southwestern and central North
Dakota, with confidence in visibility reductions highest across
south central North Dakota, and especially in the James River
Valley. Have added MVFR visibility at KJMS tomorrow morning with
this update. Any fog that does develop is anticipated to lift
by the mid morning on Monday. Winds overall remain light today,
turning out of the south southeast to the southwest this evening
and overnight.

&&

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

&&

$$

UPDATE...Adam/Anglin
DISCUSSION...Anglin
AVIATION...Adam