019
FXUS63 KBIS 081951
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
251 PM CDT Tue Jul 8 2025

.KEY MESSAGES...

- Widespread high temperatures in the 90s are expected on
  Wedneday.

- Isolated to scattered severe thunderstorms are possible late
  Wednesday afternoon and evening. Isolated severe thunderstorms
  are then possible late Thursday afternoon and evening.

- Temperatures cool down for the end of the workweek, before
  warming back up through the weekend.

&&

.DISCUSSION...
Issued at 250 PM CDT Tue Jul 8 2025

Near northwesterly flow over the northern Plains this afternoon
is expected to turn increasingly zonal through the evening as a
mid to upper level ridge slides in from the west. Generally
clear and calm conditions are expected across the forecast area
through the remainder of the day today as high pressure
continues to move in from the southern Canadian Prairies. With
this, highs today are broadly forecast from the mid 70s in north
central North Dakota up to the upper 80s in the far southwest.
Later this evening and tonight, a weak shortwave topping over
the ridge and the redevelopment of a LLJ overnight will allow
for a increase in precipitation chances in the far southwest.
Overall chances for showers are low (10 to 15 percent), but you
could get few isolated rumbles of thunder. Otherwise, low
temperatures overnight are forecast from the mid 50s east to the
mid 60s west.

With prevailing clear skies and the better penetration of the
thermal axis associated with the upper level ridge on Wednesday,
high temperatures are expected to fall broadly into the 90s
across western and central North Dakota. It would not take much
to tip portions of far western North Dakota into the lower
100s. Regarding the potential for heat headlines tomorrow,
conditions across the west, where highs are forecast in the
upper 90s, are expected to be dry, with dewpoints peaking only
into the 40s and 50s. In central North Dakota, where higher
dewpoints in the mid to upper 60s are anticipated, surface
temperatures are "only" forecast in the lower to mid 90s. Thus,
apparent temperatures across western and central North Dakota
are expected to remain below 100 F at the time of this forecast,
mainly in the lower to mid 90s. That being said, somewhat weak
winds west of Highway 83 will make conditions feel very muggy.

Now onto the severe weather potential Wednesday. Dewpoints
across central North Dakota are expected to rise in mid to upper
60s by late tomorrow afternoon. With ample near surface
moisture, an explosively unstable environment with model MUCAPE
values exceeding 3000 to 4000+ J/KG, high low to mid level
lapse rates exceeding 8 C/km, sfc temperatures approaching
convective temps, and a weak surface trough / warm front
progressing eastward through the afternoon and evening, CI is
anticipated by the late afternoon, early evening. What remains
in question is the quality of the sheared environment. CAMs are
reticent to advertise much more than 30 to 35 knots of 0-6 KM of
bulk shear ahead of the boundary, which may keep any
supercellular storms that do develop fairly transient in nature.
Thus, despite the high CAPE values, we have opted to keep the
potential hail size up to around golf balls. Of note is the high
DCAPE values advertised by CAMs at this time, with a distinct
inverted V sounding evident on BUFKIT. With this, strong wind
gusts up to 70 MPH are also expected. Otherwise, there may also
be an isolated tornado threat initially in the late afternoon,
early evening period, driven less by near surface SRH as opposed
to to the exceedingly unstable environment taping into
vorticity along the wind shift. At it stands, SPC has place
portions of south central North Dakota into a Slight (level 2 of
5) Risk for scattered severe storms tomorrow afternoon, with a
Marginal (level 1 of 5) Risk for isolated severe storms
essentially everywhere else. High PWATs around 1.6 inches are
also advertised which could promote periods of heavy rainfall in
some localized areas, though storms are anticipated to be
moving fairly quickly. Storms are expected to move across the
James River and into eastern North Dakota by the late evening,
early overnight period.

On to Thursday. Like Wednesday, and explosively unstable
informant with MUCAPE values well above 4000+ J/KG cape is
modeled over central North Dakota. Dewpoint values Thursday
afternoon are also expected to peak into the upper 60s to lower
70s by the late afternoon, early evening period, highest across
the southern James River Valley. Along with high lapse rates
exceeding 8-9 C/KM in the low to mid layers, CI is possible
ahead of a cold front passing from northwest to southwest in the
early evening. However, marginal bulk shear continues to plague
these potential storms. Current model trends keeps shear
relatively low, sub 30 knots, through much of the afternoon and
evening, though shear then increases on the backside of the cold
front. Additionally, a moderately strong cap across much of
central North Dakota may help keep CI just on the eastern edge
of the forecast area through the late afternoon and evening,
meaning that any thunderstorms that do develop would quickly
exit into eastern North Dakota. With that in mind, we are
continue to advertise hail up to the size of ping-pong balls and
wind gusts up to 60 MPH. As of the current forecast cycle, SPC
places essentially all of western and central North Dakota in a
Marginal (level 1 of 5) Risk for isolated severe thunderstorms
on Thursday. Additionally, high PWATs exceeding 1.7" plus across
central North Dakota again hint at potentially high rainfall
rates with any thunderstorm that does develop, though storms are
not anticipated to remained park over any given location for
long. Otherwise, for Thursday, high temperatures broadly in the
80s and lower 90s are anticipated.

On the backside of the cold front, cooler highs mainly in the
70s are forecast for Friday. With an upper level trough closing
off over the northern Plains, chance for showers and a few
thunderstorms will linger through the morning and early
afternoon on Friday (20 to 40 percent chances, highest across
the west). Aloft, the return of northwesterly flow ahead of
building upper level is anticipated to promote another warming
trend that brings the forecast area back into the 80 and lower
90s this weekend into early next week. With this northwesterly
flow, near daily chances for showers and afternoon thunderstorms
will continue through much of this period.


&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 250 PM CDT Tue Jul 8 2025

VFR ceilings and visibility are anticipated at all terminals
throughout the 18Z TAF period. Tonight through tomorrow morning,
LLWS is expected at KXWA from 06z to 10Z. Winds will generally
organize out of the southeast overnight, becoming breezy with
speeds up to 15 knots and gusts up to 25 knots in the northwest.
Winds then turn southerly through the morning, the gusty winds
move over central North Dakota.

&&

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

&&

$$

DISCUSSION...Adam
AVIATION...Adam