633
FXUS63 KBIS 010902
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
402 AM CDT Mon Sep 1 2025

.KEY MESSAGES...

- Patchy to areas of fog again possible this morning, mainly
  south and east.

- Isolated to scattered thunderstorms possible today and Tuesday.
  A few storms may be strong to severe.

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


- Areas of wildfire smoke may also return on Tuesday.

&&

.DISCUSSION...
Issued at 402 AM CDT Mon Sep 1 2025

Lingering low level moisture combined with light winds is making
for some low clouds and areas of fog across the west and south
central early this morning. Webcams showing dense fog to be
fairly isolated still, although this could change through the
morning hours. For now have issued an SPS to inform of the
threat of at least some areas of dense fog. If this coverage
becomes more widespread then perhaps an advisory may be needed.
A weak shortwave will move across the region today, this could
bring isolated to scattered showers and thunderstorms to the
state. A few showers may start as early as this morning in the
north. Warmer temperatures in the mid 70s to mid 80s will be
found today. This will bring higher instability across the area
today, with MUCAPE up to 1500 J/KG. The upper wave could also
provide for some modest shear around 30 knots today. These
parameters would be enough for some isolated to perhaps severe
thunderstorms. There does remain some capping concerns today
through this evening, as well as how much lift this weak wave
can provide. SPC has maintained general risk across the area
given the uncertainty. Thus the severe weather threat is more
conditional. If a stronger storm can develop, wind gusts to 60
MPH and hail to the size of a quarter would be possible.
Southerly winds will be found to start the day, with the weak
wave possibly bringing some light westerly winds. Thunderstorms
will generally diminish overnight tonight with lows forecast in
the 50s. Tuesday then sees a cold front move across the state
from north to south. Along this front could be showers and
thunderstorms. By the time this front gets to the warmer and
more unstable areas in the south, there could be an isolated
strong to severe thunderstorm. SPC now has a Marginal Risk for
southeastern North Dakota. Winds to 60 mph and hail to the size
of a quarter would be the main threats. Behind this front could
be an increased northerly wind. This front could also return
wildfire smoke from Canada across much of the state on Tuesday
and perhaps into the upcoming week. Showers and thunderstorms
may then linger across the east and south Tuesday night, with
cooler overnight lows in the 40s and lower 50s.

A breezy and cool post frontal day is forecast for Wednesday,
with highs generally in the 60s. Limited chances for
precipitation is currently forecast for Wednesday. Surface high
then moves across the state Wednesday night bringing cool
overnight lows in the mid 30s to mid 40s. Perhaps some frost may
be found Thursday morning as a result, although uncertainty in
overnight lows remains with the track of the high and perhaps
some lingering cloud cover. A weak wave may then move through
Thursday, perhaps bringing some chances for showers in the north
and east. Breezy winds may be found with this wave, although
some slightly warmer temperatures in the 60s and 70s may also be
found. A series of surface highs could then move through in the
northwest flow to end the work week and into the start of the
weekend. This could bring mainly dry conditions with continued
below normal temperatures. Friday morning may not be as cold as
Thursday, with Saturday morning currently forecast to see lows
return in the 30s and possibly bring some frost. Ridging could
then remain through the weekend, although some cluster solutions
break down this ridge earlier and indicate a change to
southwest flow pattern aloft could return later in the weekend.
This could bring slightly warmer and perhaps near normal
temperatures. If any weak waves can move through in this
potential southwest flow then perhaps some showers and
thunderstorms may return, although NBM currently maintains a dry
forecast.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1245 AM CDT Mon Sep 1 2025

Another round of fog and low clouds could move into the area
tonight into Monday morning. Confidence in fog formation is
modest tonight, although was high enough to include BR mention
from KDIK to KBIS to KJMS. Any low clouds or fog that forms
could bring IFR to LIFR conditions. Otherwise look for mainly
dry conditions tonight into Labor Day morning, with a light
southerly wind. The rest of Labor Day then looks to see mainly
VFR conditions with a light south wind, perhaps becoming
westerly later in the day, then light and variable in the
evening. Chances for showers and thunderstorms could return in
the afternoon and evening. Some sites with higher confidence
have a PROB30 group for these chances of precipitation.

&&

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

&&

$$

DISCUSSION...Anglin
AVIATION...Anglin