Mandan, North Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

832
FXUS63 KBIS 290553
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1253 AM CDT Mon Jun 29 2026

.KEY MESSAGES...

- Another round of isolated to scattered severe thunderstorms is
  possible through Monday. Main hazards will be hail up to 2
  inches in diameter and wind gusts up to 70 mph. An isolated
  tornado is possible.

- After a subtle cool down to start the week, above average
  temperatures are favored starting the middle of this week,
  potentially warming to well above average heading into the
  Fourth of July holiday weekend.

&&

.UPDATE...
Issued at 1043 PM CDT Sun Jun 28 2026

** Mesoscale Update **

A severe storm risk will continue over parts of central/north
central ND through midnight to 1 am CDT, with the main hazards
being large hail up to around 2 inches in diameter and damaging
wind gusts up to 70 mph.

Several supercells continue from around Lake Sakakawea northeast
across north central ND in an environment characterized by very
strong deep-layer shear on the order of 50-60 kt and strong
bouyancy (MLCAPE/MUCAPE on the order of 2000-3000 J/kg). Surface
dewpoints are in the 70-73 F range from Harvey to Rugby and
Bottineau, which is allowing for boundary-layer based CIN to be
low enough for maintenance of these storms past sunset. There is
a background impulse aloft helping drive the storms, but the
low-level jet is very weak, so once MLCIN increases sufficiently
these storms will weaken. RAP/HRRR guidance suggests that may
not occur in north central ND until 05-06z, so in the interim, a
severe-storm risk will continue.

Meanwhile, in south central ND the earlier isolated supercells
have weakened with sunset as MLCIN increased substantially.
Low-level water vapor imagery and radar imagery showing midlevel
echoes from northwestern SD into southwestern ND suggest forcing
for ascent still encroaching on the area -- and likely driving
the downstream supercells -- but the overall forcing may not be
enough to overcome increasing inhibition after 05 to 06z. We
will be watching for upstream strong-severe storms which have
begun developing in southwestern SD/north central NEB to move
northeastward late tonight. However, recent CAMs including the
00-02z HRRR cycles and 00z HREF members suggest those storms may
be more probable to impact northeast SD and far southeastern ND
late tonight and early Monday morning. They could impact parts
of the southern James River Valley of ND, though, so will
require close monitoring overnight.

CJS

.DISCUSSION...
Issued at 345 PM CDT Sun Jun 28 2026

Upper low will linger to the northwest tonight. Meanwhile a
surface low developing in the across the central plains will
continue to provide ample moisture and instability to the area.
The result will likely be another round of thunderstorms
tonight, especially late tonight. Currently there is high
amounts of instability and shear, some of it minimally capped,
although capping may return this evening. However, lift is
limited at the moment given the two mentioned lows are not quite
to the area. A favorable jet location has been enough to develop
some elevated showers and thunderstorms this afternoon, and may
continue to do sot through at least the early evening. Chances
for severe weather with these storms will be limited given the
elevated nature of the storms. Later this evening and especially
through the night, embedded waves rotating around the upper low
combined with a northward shift of the surface low will bring
higher chances for showers and thunderstorms. These storms could
tap more into the high amounts of instability and shear,
although may still remain somewhat elevated. However, the high
amounts of shear (with a shear vector angled to perpendicular
at times) could support rotating yet elevated supercells. Thus
hail up to 2 inches will be the main threat. High 0 to 3 KM
shear and adequate DCAPE would support wind gusts to 70 mph.
This wind could be in excess of 80 mph as some CAMs have the
upper level jet intersecting the MUCAPE axis. This is a lower
confidence scenario but one to keep an eye out for late tonight
into Monday morning. Given the elevated nature of these storms,
the tornado threat is low tonight although an STP greater than
1 and the possibility of supercell interactions will bring at
least some low chances for tornadoes. SPC has maintained a
Marginal to Slight Risk for severe weather potential, mainly for
the storms overnight tonight. Otherwise look for lows in the 50s
and 60s tonight. Any clearing combined with light winds could
bring some patchy fog tonight, although confidence in this
development is low at this time.

Widespread showers and thunderstorms, with isolated to
scattered severe storms, could then be found Monday morning and
throughout the day Monday. SPC has a Marginal to now Slight Risk
for severe weather Monday, with a focus on Monday morning and
any redevelopment Monday afternoon. Fairly similar setup for
late tonight will the upper low moving more into the area and
the surface low moving through. High amounts of shear and cape
will be found during this time period. The angle to the shear
vector is somewhat uncertain as it will depend on the boundary
storms form on. Thus a mix of multi cell and super cells are the
likely. The same hazards will be likely with hail up to 2
inches in diameter, winds to 70 mph, and perhaps an increase to
the isolated tornado threat. Of concern are the potential for
multiple rounds of severe weather Monday, the first being right
way in the morning and the second in the afternoon. Thunderstorm
chances then start to diminish in the evening as the upper low
moves north. Otherwise look for slightly cooler temperatures on
Monday except across the southeast where mid to upper 80s are
forecast. Some higher dewpoints in the southeast could also
bring some moderate heat risk. Chances for showers and
thunderstorms retreat to the north Monday night, with low threat
for severe weather as instability decreases. Lows in the upper
40s to upper 50s are forecast.

Other than a few stray showers or thunderstorms, Tuesday
through Tuesday night then looks mostly dry. NBM forecast today
came in with much stronger west winds for Tuesday, indicating
advisory level winds possible. ECMWF EFI values have increased
somewhat, and are currently highlighting the Highway 2 corridor.
Something to monitor going forward. After which, periodic
showers and thunderstorms are possible through the weekend as
embedded shortwaves within southwesterly to westerly flow aloft
push through the region. Though some uncertainty remains,
deterministic models are in fair agreement that direct Gulf
moisture will frequently be cut off during most, though not
necessarily during all time periods. How this evolves will
highly impact severe potential during the Holiday weekend, as
well as just how high heat indices become.

High temperatures will gradually increase through the week as a
ridge builds over the Northern Plains and Midwest, with the
current NBM favoring the warmest day overall as July 3rd. This
includes the warmest ambient and apparent temperatures. Latest
NBM does show a potential slight cooling trend this weekend as
an upper low breaks down ridging over the Northern Plains.
However, moderate uncertainty remains in regard to the forecast
for the holiday weekend.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1253 AM CDT Mon Jun 29 2026

Scattered showers and thunderstorms are expected through the
night tonight. Shower and thunderstorm coverage is then expected
to increase during the day Monday, especially for central and
eastern North Dakota. A few severe thunderstorms are present
over north central North Dakota as of this writing, though will
likely become sub-severe over the next couple hours. Additional
severe thunderstorms are possible during the day Monday, and
should end from south to north in the evening. IFR
ceilings/visibility and erratic winds are possible with any
showers and thunderstorms that develop. In addition to shower
and thunderstorm chances, patchy fog may develop along and east
of Hwy 83 overnight, while MVFR/IFR ceilings should continue
expanding across much of south central and eastern North Dakota
overnight.

&&

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

&&

$$

UPDATE...CJS
DISCUSSION...Anglin
AVIATION...Telken