359
FXUS63 KBIS 231745
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1245 PM CDT Sat Aug 23 2025

.KEY MESSAGES...

- Well below average temperatures today through Monday, with
  highs mostly in the mid 60s to mid 70s and lows in the 40s.

- Chances for precipitation are very low through the middle of
  next week.

&&

.UPDATE...
Issued at 1245 PM CDT Sat Aug 23 2025

Diurnal cumulus / stratocumulus has developed across much of
western and central North Dakota at the time of the mid day
update. Have modified sky grids to account for this development,
but otherwise no other changes to the forecast were performed.
Overall, the forecast remains on track.

UPDATE
Issued at 950 AM CDT Sat Aug 23 2025

Clear, calm, and dry conditions persist across western and
central North Dakota at the time of this mid morning update. The
lingering low to mid level stratus over the James River Valley
earlier this morning has all but dissipated/shifted eastward by
now, with the only real cloud cover to be found being a thin
band of mid level clouds associated with a weak upper level
impulse found in the northwest. Have blended in the latest
satellite and model trends in the sky grids with this update.
Otherwise, no other adjustments to the forecast were performed
at this time, as the it remains broadly on track.

UPDATE
Issued at 638 AM CDT Sat Aug 23 2025

Overall quiet weather this morning, with the main area of low
clouds seen on nighttime satellite imagery moving through the
James River Valley, with a few patches of cloud cover in the
Turtle Mountains area and in the northwest. Freshened up sky
cover, otherwise no changes needed with this update.

&&

.DISCUSSION...
Issued at 358 AM CDT Sat Aug 23 2025

Early this morning, a deep low aloft was analyzed over Ontario
while an upper high was placed over the Four Corners Region,
leading to cyclonic flow over the Dakotas in between these
features. At the surface, very broad high pressure was centered
over Saskatchewan, and was beginning to slide into western
North Dakota. A modest pressure gradient over the eastern half
of the state has kept northwest winds somewhat breezy through
the overnight hours, while winds are much lighter to the west.
Increased low-level humidity has kept a modest area of scattered
low stratus across the north central, and with forecast
RAP/HRRR soundings showing this trend continuing through the
morning, did bump up cloud cover some for north central and far
eastern counties. Rest of the forecast area should have a good
amount of sunshine.

Seasonably cool air will continue to filter into the region
today, with forecast highs in the mid 60s to lower 70s. An
embedded shortwave and potentially weak cold front will drop
south this evening, with high-res guidance advertising scattered
showers across eastern North Dakota. Current thought is that
this activity will stay just east of the forecast area, and
carrying a dry forecast for now, with a 10 percent chance of
showers in our eastern tier of counties (from the Turtle
Mountains area through Jamestown area and south). Lows tonight
will be around 10 degrees below average, in the 40s.

Sunday looks quite similar to today as northwest flow aloft
persists and the surface high begins to move overhead, which
will keep winds relatively light. Highs on Sunday will again be
generally in the mid 60s to lower 70s, with partly cloudy skies
north central and east, and mostly sunny skies elsewhere.

If deterministic guidance is correct, the surface high will be
centered over central / eastern Dakotas on Monday morning,
potentially over the Aberdeen SD area which local research has
shown is very favorable for overnight lows to drop cooler than
forecast. This is somewhat illustrated in current NBM
probabilities, with the chance of lows below 40 F Monday
morning showing a corridor of still low but notable
probabilities from Hettinger to Beulah/Hazen, our normal cold
area. There are similar probabilities across the far north, so
would not be surprised if we have some locations dropping into
the upper 30s Monday morning.

As the dominant upper low to our northeast slowly meanders off
to the Hudson Bay area to start the work week, very broad
ridging over the western CONUS will be able to start expanding
east. There is high confidence in NBM temperature percentiles of
a short-lived warming trend through Wednesday to get
temperatures back closer to normal (upper 70s to lower 80s),
with very low chances for precipitation during this time. As
previous shift noted, there is a subset of ensemble members,
around 25 percent, that keep flow a bit more northwesterly over
the Northern Plains, in response to the downstream upper low
not progressing as quickly as expected. This would keep
temperatures slightly cooler and would also introduce higher
probabilities of precipitation late in the work week. For now,
NBM has rain chances capped around 20 percent in the far south
during this time, with highs in the mid 70s to lower 80s.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1245 PM CDT Sat Aug 23 2025

VFR ceilings and visibility is anticipated at all terminals
throughout the 18Z TAF period. Breezy north to northwest winds
across northern and central North Dakota this afternoon are
anticipated to diminish through the early evening, becoming
light through the overnight period.

&&

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

&&

$$

UPDATE...Adam/Jones
DISCUSSION...Jones
AVIATION...Adam