898
FXUS63 KBIS 040948
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
448 AM CDT Mon Aug 4 2025

.KEY MESSAGES...

- Patchy to areas of dense fog this morning for western and
  central North Dakota.

- Periodic isolated to scattered showers and thunderstorms are
  forecast through the week. Isolated severe thunderstorms are
  possible on Tuesday.

- A gradual warmup is expected through mid-week. Some highs
  approaching 90 return to the forecast Wednesday and Thursday.

&&

.DISCUSSION...
Issued at 439 AM CDT Mon Aug 4 2025

Weak flow aloft will continue through the short term causing
remnant smoke to linger across the region. Dew points in the
60s and low temperatures in the 60s has reached saturation. In
addition cloud condensation nuclei from smoke is promoting
areas of fog across the region. Fog has lead to widespread
visibility reductions across the state this morning. Therefore,
a Dense Fog Advisory has been issued for visibility down to one
quarter of a mile until around 13Z. Fog is forecast to burn off
as temperatures warm up after sunrise. Hazy skies will likely
persist today as there is some elevated smoke aloft.
Temperatures are forecast to warm into the mid 70s out east and
the upper 80s as a weak ridge amplifies across the western
Dakotas this afternoon. Following the upper level ridge a trough
is forecast to dig across the Northern Rockies today leading to
convection over the higher terrain of Montana. The CAMs have
remnant storms moving close to the state line late tonight.
Storms will likely be weakening by the time they approach the
North Dakota border.

Tuesday the trough is forecast to move across the state leading
medium chances of precipitation. Showers and thunderstorms could
linger through the morning hours as they move out of Montana.
There is a chance for isolated to scattered severe storms
Tuesday afternoon and evening. Hi-res models are forecasting
around 1500-2200 J/kg of SBCAPE and around 30 to 40 kts of 0-6
km wind shear. The higher CAPE values will be near the North and
South Dakota border where a slight risk is. The CAMs are
highlighting the strong storms going up in the afternoon evening
hours. The is some uncertainty on the mode of storms if they
will be more discrete or cluster like before coming more linear
by night fall. High temperatures will decrease a few degrees
into the upper 70s to lower 80s. Showers and thunderstorms will
move eastward overnight across the eastern half of the state.

Showers and thunderstorms will carry through Wednesday morning
bringing rain to much of the state. There is a 50 percent chance
for half of inch of rain across south central North Dakota into
the James River Valley from this system. Probability decrease
for an inch but with system being mostly convective, thus I
would not be surprised to see localized areas with an inch or
more of rain. Machine learning is pegging Thursday and Friday
for the return of severe weather. The jet stream returns by the
end of the week with multiple waves moving through the main
flow which could lead to severe weather. In addition
temperatures will warm back up Thursday warming into the 80s to
lower 90s promoting increased instability. The weekend looks
fairly active as an upper level low moves across the region
bringing in widespread precipitation.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1230 AM CDT Mon Aug 4 2025

IFR and MVFR conditions are possible under low stratus and fog
tonight through tomorrow morning. Low stratus is forecast to
expand across the state early this morning leading to areas of
dense fog. Amendments will be made as ceiling and visibility
bounce around. Winds will remain light and variable. Fog and low
stratus will burn off a little bit after sun rise leading back
to VFR conditions.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 8 AM CDT /7 AM MDT/ this morning for
NDZ001>005-009>013-017>023-025-033>037-041-042-045>048-050-051.

&&

$$

DISCUSSION...Johnson
AVIATION...Johnson