Mandan, North Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

032
FXUS63 KBIS 130606
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
106 AM CDT Fri Jun 13 2025

.KEY MESSAGES...

- Below average temperatures through Friday, then near average
  this weekend through next week.

- Daily low to medium chances for showers and thunderstorms this
  weekend through next week. A few strong to severe storms are
  possible each day.

&&

.UPDATE...
Issued at 1258 AM CDT Fri Jun 13 2025

Scattered showers continue over much of the area, with a bit
greater coverage over the southern James River Valley. Expect
the coverage to gradually diminish as we continue through the
night into the early morning hours. Otherwise, the other concern
is possible fog development. Have expanded areas of fog through
much of the southwest as visibility continues to gradually
diminish, and spread patchy fog through most remaining southern
areas per latest guidance.

UPDATE
Issued at 1038 PM CDT Thu Jun 12 2025

We felt another update was warranted to mention that we removed
thunder for most of the area outside of the far southern James
River Valley. Also, scattered showers continue to redevelop
ahead of the S/WV and with easterly upglide flow, so re-
increased POPs a bit for the next few hours and went with
coverage wording. Overall, a pleasant early Spring night
(despite it is mid-June).

UPDATE
Issued at 936 PM CDT Thu Jun 12 2025

There were no major changes to the forecast at this time. Scaled
back on thunder potential with most areas outside of the
southern James River valley stable. Will maintain a heavy
rainfall wording in the HWO across this same area (our far
southeast), with training storms still possible over the next
few hours.

UPDATE
Issued at 638 PM CDT Thu Jun 12 2025

Main forecast updates with this product issuance was mainly to
increase the fog potential southwest a bit. Also blended hourly
weather elements based on latest sfc obs and trends. Overall,
minimal changes were needed. See below for more detailed
discussion.

&&

.DISCUSSION...
Issued at 347 PM CDT Thu Jun 12 2025

Negatively-tilted mid level troughing is analyzed from southern
Alberta to the southern Red River Valley this afternoon. A pair of
distinct shortwaves, over southwest Saskatchewan and eastern North
Dakota respectively, can be seen on water vapor imagery with mid
level drying evident through South Dakota. Shower and thunderstorm
activity has unfolded as expected across central North Dakota, but
is significantly less than expected in western parts of the state.
Recent CAMs hint at some redevelopment later this afternoon and
evening, but confidence in this outcome keeps trending lower.
Meanwhile, there is marginally sufficient buoyancy on the order of
around 500 J/kg MUCAPE from south central to southeast North Dakota
to support a few thunderstorms. So far this afternoon, observed
lightning has been sparse and mainly limited to Grant and Sioux
Counties. Switching gears, near-surface smoke has notably improved
across the state but still exists at lower concentrations across the
north. It may take until Friday night for the smoke to fully
disperse, but conditions are not expected to worsen significantly
beyond current observations.

This evening through tonight, strong low level frontogenesis is
forecast to develop over the southern James River Valley and remain
nearly stationary. Moisture transport feeding into the resultant
warm frontal boundary underneath strong cyclonic curvature vorticity
should provide enough lift for widespread showers and likely at
least a few thunderstorms to persist over this part of the region
for much of the evening and overnight periods. Several ingredients
are in place that could promote high rainfall rates, including
precipitable water around 1.25 to 1.5 inches and warm cloud depths
around 3000-3500 m. Additionally, forecast storm motion/deep layer
wind vectors oriented perpendicular to the moisture transport
vectors could yield training convection. The 12Z HREF localized
probability-matched mean QPF paints a swath of 2-4 inches from
Dickey County eastward, and its ensemble maximum QPF approaches 5
inches. Widespread flooding concerns are not anticipated with this
event, but localized minor flooding of urban and poor drainage areas
is a reasonable outcome given this setup.

Mid level cyclonic flow on top of a diffluent easterly surface flow
is forecast to maintain cloud cover across much of western and
central North Dakota on Friday, limiting forecast high temperatures
to the 60s. Mostly dry weather is expected on Friday, with a few
lingering light showers possible in the morning. Friday morning
could also feature fog across the southwest, but it is uncertain how
dense the fog will be, and this could be a case of ceilings lowering
to the surface along areas of higher terrain. Strong to severe
convection is forecast to approach the MT/ND border Friday evening,
but there is strong model/ensemble consensus that the threat for
severe weather will not expand into western North Dakota.
Nevertheless, there are still increasing chances for showers and a
few sub-severe thunderstorms from western into south central North
Dakota Friday night.

For this weekend through most of next week, ensembles favor broad,
low-amplitude upper ridging over the Northern Plains with
intermittent shortwaves temporarily flattening the ridge. This
results in a slight warmup back to near normal temperatures, with
forecast highs mainly in the 70s to lower 80s. Given the expected
more active pattern but with high timing uncertainty on shortwave
passages, the NBM maintains nearly continuous low to medium rain
chances from this weekend through the middle of next week. Boundary
layer moisture is also forecast to increase over this time period,
which in turn should yield instability/buoyancy that is more
favorable for strong to severe convection. Machine learning guidance
shows low probabilities for severe storms nearly every day through
the extended period, with no one particular day standing out above
the rest. Forecast details on any severe weather will remain very
uncertain at longer time ranges, but this is the most ensemble
support for stronger convection there has been so far this
season.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1258 AM CDT Fri Jun 13 2025

Scattered rain showers will gradually taper off overnight into
early Friday morning. Ceilings will continue to lower to MVFR
and eventually IFR levels from southwest to northeast through
the forecast period. These lower ceilings may only reach as far
northeast as KMOT late Friday morning. Southern North Dakota
could see LIFR ceilings overnight into Friday morning, along
with fog in the southwest.

&&

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

&&

$$

UPDATE...JJS
DISCUSSION...Hollan
AVIATION...JJS