584
FXUS63 KBIS 030245
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
945 PM CDT Wed Jul 2 2025

.KEY MESSAGES...

- Low chance for strong to severe thunderstorms across the
  northwest late tonight with damaging winds up to 60 mph and
  large hail up to quarter size being the main threats.

- Isolated to scattered severe thunderstorms are possible
  Thursday afternoon into the night. The main hazards are golf
  ball size hail, damaging winds up to 70 mph, and an isolated
  tornado or two.

- Thunderstorm chances will continue Friday with a low chance
  for severe weather out east.

- Warm and humid conditions tomorrow and Friday with a cooling
  trend through the rest of the weekend. Daily thunderstorm
  chances will carry over into early next week.

&&

.UPDATE...
Issued at 945 PM CDT Wed Jul 2 2025

For western and central North Dakota, have tweaked the cloud
cover a bit to account for the latest satellite trends. Upstream
of the forecast area, scattered showers and thunderstorms have
moved into eastern Montana. The inciting surface boundary
associated with these storms is somewhat slow moving, and isn`t
expected to make it to our western counties for another two to
three hours. CAPE is relative low across this region, at most
around 500-1000 J/KG and is already beginning to fall. All the
while, CIN continues to expand across the forecast area. With
this in mind, the storms in eastern Montana may struggle to stay
together long enough to make it into northwestern North Dakota
without become more general showers and a few rumbles of
thunder. That being said these storms are putting down a decent
amount of rain which, along with their slow-going nature, means
we will need to monitor then for potential flash-flooding
concerns (though probability for such remains low at this
time).


UPDATE
Issued at 635 PM CDT Wed Jul 2 2025

Quiet weather continues across western and central North Dakota
at the time of this early evening update. Further upstream,
showers and thunderstorms have begun to develop along a surface
trough in central Montana. This trough, and accompanying
storms, are not anticipated to reach our western counties until
late this evening or early tonight. We will continue to monitor
these storms as they approach. An interrogation of BUFKIT model
soundings during this period reveals a somewhat decent near
surface inversion over south central North Dakota tonight
through the mid morning hours on Thursday. While southwesterly
winds remain somewhat elevated overnight, fog is possible
wherever winds die down and in low lying areas. Thus, have added
in some patchy fog into the far south central into the James
River Valley area for early tonight through the mid morning
hours Thursday. Otherwise, have made some slight adjustments to
the PoPs to account for the latest model trends.

&&

.DISCUSSION...
Issued at 337 PM CDT Wed Jul 2 2025

An upper level ridge continues to progress over the Northern
Rockies this afternoon lifting a low-level thermal ridge
across the High Plains of Montana. Thus, some sites in far
western North Dakota have already touched the lower 90s. High
temperatures this afternoon are forecast to warm into upper 80s
to lower 90s. A weak wave will traverse the upper level ridge
late tonight bringing forth thunderstorms to the northwest.
There is a low chance that these storm could be severe with
gusty winds up to 60 mph and quarter size hail. The CAMs are
highlight a weakening quasi-linear cluster of storms dissipating
in the northwest around midnight. Overnight lows are forecast to
sit in the 60s tonight.

Tomorrow, the upper level ridge axis is forecast to pass over
the Northern Plains. This will likely be one of the warmest days
this week with temperatures forecast to climb into the 90s
across the western and central North Dakota with a few sites
nearing triple digits. In addition, a north south orientated
surface pressure gradient will bring forth a low level jet
around 20 mph that will pull in 60s dewpoints across the state.
High dewpoints and high temperatures will lead to hot and muggy
conditions tomorrow.

Surface low pressure and an upper level wave is forecast to
move in from eastern Montana tomorrow. This will lead to the
potential for thunderstorms. Tomorrows environment supports a
chance for isolated to scattered severe storms tomorrow
afternoon. MUCAPE is forecast to sit around 2500-3500 j/kg with
around 30-40 kts of 0-6 km bulk shear. Forecast sounding were
originally showing a substantial cap hindering initiation, but
the latest CAMs have come in with little to no cap tomorrow
afternoon. Forecast hodographs do have a few hours of low level
curvature which could support a tornado or two if storms become
surface based. The aforementioned upper level wave and
convective temperature could play a roll in storm initiation
tomorrow afternoon with the low level jet supporting storms
after development. The mode of the storm could start out as
discrete supercells organizing into a line late tomorrow tonight
with some HREF members hinting at an MCS. The main hazards are
golf ball size hail, 70 mph winds, and a tornado or two.

The upper level ridge axis is forecast to move across eastern
North Dakota and eastern Minnesota Friday. This will lead to
another round of hot temperatures across the eastern half of the
state. An upper level short wave is forecast to move through
the region bringing in chances for thunderstorms. In addition
precipitable water is forecast to increase across the eastern
half of the state ranging from 1.5 in Bismarck to 1.8 in Fargo
which could lead to the heavy rain potential. The heavy rain
will be more localized as the NBM probabilities of an inch or
more of precipitation are low through Saturday. There is an
isolated risk for severe weather out east Friday afternoon
clipping the southern James River Valley.

An upper level trough will pass across the region Saturday
leading to increased rain chances and cooler temperatures. The
wrap around precipitation from the upper level low is forecast
to bring in showers and thunderstorms Saturday morning with
another wave following suit Sunday. Temperatures will drop back
down into the upper 70s to lower 80s this weekend. Next week we
could see a return of severe weather as the upper level pattern
returns to zonal flow with multiple waves moving through the
region. CSU machine learning program is pegging Monday and
Tuesday for having low chance of severe weather.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 945 PM CDT Wed Jul 2 2025

VFR ceilings and visibility is mainly anticipated at all
terminals throughout the 00Z TAF period. Showers and isolated
thunderstorms, one or two of which may be stronger, are possible
in the northwest late this evening through the early overnight,
including at the terminal of KXWA, before diminishing early
Thursday morning. Have included a PROB30 group for -TSRA at KXWA
with this update Patchy fog may be possible in the south east,
including over the James River Valley, the the chance of this is
too low to include at any given TAF site at this time. Tomorrow
afternoon, showers and scattered thunderstorms are possible in
the northwest and north central. Some of these thunderstorms may
become strong to severe, with large hail up to the size of golf
balls, wind gusts up to 70 MPH, and a tornado or two being
possible with any severe thunderstorm that does develop. Have
include another set of PROB30s at KXWA and KMOT for -SHRA with
this update mid Thursday afternoon through the end of the TAF
period. Showers and thunderstorms are expected to become more
widespread beyond the end of the TAF period, sweeping from west
to east through Thursday evening and overnight. Southeast winds
are expected to become gusty across the north as a low level jet
sets up overnight, with wind speeds up to around 15 knots and
gusts up to 25 knots expected. Winds are then expected to turn
southerly Thursday morning and afternoon, with moderate winds
with sustained speeds up to 20 knots and gusts up to 30 knots
possible across south central North Dakota. Where showers and
thunderstorms do develop tonight or Thursday afternoon, gusty
and erratic winds can be anticipated.

&&

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

&&

$$

UPDATE...Adam
DISCUSSION...Johnson
AVIATION...Adam