516
FXUS63 KBIS 180632
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
132 AM CDT Sat Jul 18 2026

.KEY MESSAGES...

- Seasonably warm temperatures are expected Saturday, with hot
  conditions returning Sunday.

- Scattered severe thunderstorms are possible Sunday afternoon
  and evening.

- Temperatures are favored to fall closer to normal next week,
  with forecast highs mostly in the 80s.

&&

.UPDATE...
Issued at 130 AM CDT Sat Jul 18 2026

Just a couple of minor adjustments were made to the near-term
forecast for this update. One was to decrease overnight low
temperatures as some locations have already fallen below the
inherited forecast. The other was to add a mention of patchy fog
from south central North Dakota to the James River Valley where
surface dewpoint depressions are very low underneath broad high
pressure. This should be more of a shallow ground fog type
event if it materializes.

UPDATE
Issued at 949 PM CDT Fri Jul 17 2026

A few models hint at a little patchy fog developing tonight as
high pressure centers over the state. However, model forecast
soundings suggest very dry air prevailing overall near the
surface. Therefore, for the most part, wouldn`t expect much more
than very shallow fog mostly confined to fields, lower bridges
over streams/rivers, etc.

UPDATE
Issued at 643 PM CDT Fri Jul 17 2026

Showers that were present in the southwest and south central
have generally moved into South Dakota, though are also in the
process of dissipating. All in all, the forecast remains on
track.

&&

.DISCUSSION...
Issued at 250 PM CDT Fri Jul 17 2026

Currently the large upper level ridge continues over the
western United States. This ridge is carrying upper level
Monsoon moisture from Arizona, through the northern Rockies, and
over through the Dakotas. This moisture has brought in elevated
showers into southwest North Dakota this morning, and they now
continue in the south central. Along with these showers is a
large area of mid level clouds across the southern half of the
state. These clouds are prohibiting anymore diurnal heating, and
most of the south is stuck in the upper 70s. This area will
likely not hit the NBM high of the lower 90s.

This weekend the very hot ridge will continue, leading to high
temperatures back in the lower 100s by Sunday. Saturday night a
very very slight shortwave could form off the Montana mountains
and bring some showers to the state. The NBM chances have
really backed off on them this morning, and that is nicely
reflected in the global models as well. Sunday the ridge axis
moves directly over North Dakota, bringing the warmest
temperatures of the weekend in. Expects highs along and west of
the Missouri River to be in the lower 100s. We will likely need
a Heat Advisory for Sunday. Elsewhere will be in the lower to
mid 90s. Sunday evening and night a weak cold front will sweep
through, leading to a very breezy Monday. From this, the north
on Monday will be cooler in the upper 70s and lower 80s, while
the south will stay in the 90s. Since the state has had very
little rain and very hot temperatures, the grasses have started
to brown. With the potential of 40 mile per hour northwest
winds, the brown grass, and low humidities, we have started to
message near-critical fire weather concerns across the
southwest on Monday.

For the rest of next week, the warming trend will restart after
Tuesday. Tuesday the upper level pattern turns to the northwest,
leading to the coolest day of the week. Expect highs in the mid
70s north to lower 80s south. The rest of the week the ridge
builds back in, starting the warming trend all over again.
Temperatures could return to the upper 90s by next week. The NBM
percentile ranges are starting to hint at that by next Friday.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 130 AM CDT Sat Jul 18 2026

Some patchy fog could develop from KBIS to KJMS late tonight
into early Saturday morning, but think it would be more of a
shallow fog scenario. Otherwise, VFR conditions are expected
through the forecast period. Expect predominantly south to
southeast winds across the western half of the state, with
speeds during the day Saturday ranging from near 15 kts at KXWA
and KDIK to only around 5 kts at KJMS.

&&

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

&&

$$

UPDATE...Hollan
DISCUSSION...Smith
AVIATION...Hollan