035
FXUS63 KBIS 270237
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
937 PM CDT Sat Sep 26 2026

.KEY MESSAGES...

- Showers and thunderstorms late Sunday evening through Monday
  night. There are medium to high chances to exceed 1 inch of
  rain from south central to northeast North Dakota. A few
  storms could be strong.

- Temperatures favored to remain near to slightly above normal
  until late next week.

&&

.UPDATE...
Issued at 937 PM CDT Sat Sep 26 2026

Overall, the cold frontal boundary has stalled in south central
North Dakota, though continues to gradually move eastward in
the north central. Dewpoints in the upper 50s and low 60s
persist east of the front, but dip into the 30s in western ND.
Overall, this should keep conditions generally fog free in the
west and north central. However, fog development has recently
been observed ahead of the frontal boundary, including in south
central parts of the state. As the entire front starts moving east
again tonight, fog should dissipate from west to east as much
drier air continues filtering in.

UPDATE Issued at 654 PM CDT Sat Sep 26
2026

Models are suggesting fog development again tonight in the south
central and James River Valley. This is contrary to rapidly
drying dewpoints and model forecast soundings that aren`t the
most bullish. However, mostly clear skies and light winds
should lead to decent radiational cooling. Therefore, opted to
add patchy fog for tonight into Sunday morning that dissipates
from northwest to southeast.

&&

.DISCUSSION...
Issued at 145 PM CDT Sat Sep 26 2026

Currently a cold front is sweeping through the state west to
east, clearing out the low stratus clouds. Behind the front
winds are gusting up to 30mph. This trend will continue through
the evening. In the low stratus mist and sprinkles are falling,
reducing visibilities at times. Aloft a large broad trough has
formed across the Pacific Northwest. The rest of this weekend
will be in the 60s to lower 70s. That broad trough will bring
southwest flow back into the state Sunday, leading to showers
and thunderstorms beginning Sunday evening south of the
interstate. After sunset, the chances will increase as a
disturbance from the Rockies forms a surface low and moves into
the Dakotas.

Showers and thunderstorms will continue through
Monday as a shortwave and front move in behind the low. There is
a chance for thunderstorms as there will be 200-500 J/kg of
MUCAPE available Sunday night with 40-50kts of shear. Severe
storms cannot be ruled out Sunday with a potential low level jet
across the Dakotas, but as of now it remains a very low risk.
Monday some models have a small axis of 1000 J/kg of MUCAPE but
others don`t, so again low confidence in severe storms Monday,
but not zero. Monday with the surface low in northern South
Dakota cold air funnels or even a legit tornado could maybe be
possible but it would be a very conditional risk. Through these 3
period there are medium to high chances of at least 1 inch of rain.

The rest of the week zonal flow takes over the northern CONUS,
keeping temperatures seasonal in the mid 60s. Afternoon
humidity values will lower back under 50 percent. Overnight lows
will hang around the mid 40s and possibly upper 30s in the far
north. Looking towards next weekend another shortwave could move
in, lowering highs into the 50s with a chance of rain.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 654 PM CDT Sat Sep 26 2026

For the most part, VFR ceilings and visibility are expected
through the period. The main exception is that patchy fog may
develop tonight into Sunday morning in the south central and
James River Valley. This could impact both KBIS and KJMS, though
what does develop should dissipate from northwest to southeast
as drier air moves in. Due to low confidence, used VCFG during
the time periods most likely for fog development at either
terminal.

&&

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

&&

$$

UPDATE...Telken
DISCUSSION...Smith
AVIATION...Telken