227
FXUS63 KBIS 071750
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1250 PM CDT Mon Jul 7 2025

.KEY MESSAGES...

- Isolated to scattered strong to severe thunderstorms (40 to 70
  percent chance) are possible this afternoon over south
  central and parts of eastern North Dakota.

- Temperatures trend warmer through the middle of this week,
  peaking on Wednesday when widespread 90s are expected for
  daytime highs.

- A chance for strong to severe thunderstorms increases across
  the region Wednesday and again Thursday and Thursday night,
  followed by cooler temperatures to end the work week.

&&

.UPDATE...
Issued at 1250 PM CDT Mon Jul 7 2025

For forecast updates, have added in some slight chances for rain
showers in northwestern North Dakota, where cumulus has
developed ahead of a wind shift dropping in out of the southern
Canadian Prairies. Otherwise, the forecast remains broadly on
track at the time of this update.

UPDATE
Issued at 945 AM CDT Mon Jul 7 2025

Scattered showers and thunderstorms continue to move eastward
over south central and the James River Valley this morning. Some
additional development on the southern tip of the LLJ near the
ND/SD border has been evident over the last hour or so. These
ongoing storms may help diminish the severe weather potential
across south central ND later today as the main wave moves into
an already worked over environment, but we will continue to
monitor conditions. Visibility reductions across northwestern
and north central North Dakota due to patchy fog continue to
slowly improve, though a few holdouts of sub 6 mile visibility
remain. DOT cameras reveal that this fog is relatively shallow,
and thus it is still anticipated to lift over the next hour or
so. Overall, the forecast remains on track at this time.

UPDATE Issued at 615 AM CDT Mon Jul 7 2025

Lead mid level impulses and a modest LLJ both contributing to
scattered showers and a few isolated thunderstorms this morning
across parts of central North Dakota. This activity will
continue to move east with the mid level features over the next
few hours. Main wave will then move in from the northwest later
this morning and afternoon, when convective redevelopment is
forecast along and east of a frontal boundary. Tweaked POPs and
sky cover based on latest imagery and trends, overall the
forecast is on track.

&&

.DISCUSSION...
Issued at 345 AM CDT Mon Jul 7 2025

Currently, embedded mid level S/WV tracking east-southeast
across southern Saskatchewan early this morning, with additional
more subtle waves in zonal flow aloft moving east across North
Dakota. These waves and a modest LLJ results in a handful of
radar returns/showers across parts of western and central ND,
popping up at various locations. Opted to keep a mention of
thunder in the forecast with these showers as earlier had a few
lightning strikes, though MUCAPE is almost non-existent this
morning.

Aforementioned S/WV and its associated frontal boundary will be
the focus for a round of strong to severe thunderstorms later
this morning and into the afternoon. MUCAPE and shear remains
marginal, though coupled with upper level support a few stronger
updrafts will be possible. SPC maintains a Marginal Severe
outlook for parts of southwest, south central, and eastern
areas of the state, and a Slight Risk area from the James River
Valley into the Red River Valley. The Slight Risk area is where
CAM`s are in better agreement with Updraft Helicity tracks and
projected reflectivity. This is also where the better shear and
CAPE combine with frontal and upper level forcing at peak
heating. By this evening, both the mid level wave and FROPA is
to our east, with a mostly clear sky and dry weather for this
evening and tonight.

Tuesday will see northwest flow aloft and sfc high pressure over
the region, with a building upper level ridge across the western
CONUS. Dry weather and temperatures trending warmer are
forecast.

Temperatures continue to trend warmer into the middle portions
of the week, as the aforementioned broad ridging develops
farther east across the Rockies and into the Great PLains.
Temperatures look to peak on Wednesday, with daytime highs well
into the 90s west and central. Highs near 100 are very possible
across the west as mixing winds become more westerly. Despite
elevated temperatures, relative humidity will be low resulting
in Heat Indices at or below ambient temperatures, so right now
doubtful heat headlines will be needed. Embedded waves and a
nocturnal LLJ could trigger late day/nighttime convection both
Tue and Wed nights (better chance Wed night) with plenty of
elevated MUCAPE available.

Models continue to project another strong mid level
trough/closed low approaching and moving through the region Thu-
Friday, with an associated cold FROPA favored to move through
west/central ND during Thursday afternoon-Thu night. The FROPA
combined with strong forcing aloft, ample instability, but
marginal shear could be the focus for strong to severe
convection Thu/Thu night. Best shear trails the best MUCAPE, so
still some uncertainty on how this plays out.

Ensembles put the upper wave over the Northern Plains on
Friday, along with much cooler temperatures and decent chances
for showers/thunderstorms. Thereafter, flow transitions to more
zonal, favoring dry weather and temperatures trending warmer
again.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1250 PM CDT Mon Jul 7 2025

VFR ceilings and visibility are mainly expected at all TAF sites
throughout the 18Z TAF period. Pockets of low stratus linger
over north central North Dakota at the time of this update, and
may occasional coalesce into MVFR ceilings over KMOT through the
early afternoon. Scattered showers and thunderstorms are moving
eastward over south central North Dakota, with more development
possible across the James River Valley later this afternoon. The
confidence in the location of this development is too low to
include mentions of storms at any given TAF site at this time,
though have included a PROB30 -SHRA at KJMS with this update. Some
storms may become strong to severe, with large hail and gusty
winds possible with whatever severe storms that do develop.
Otherwise, patchy fog may be possible across the James River
Valley tomorrow morning. This fog may be restricted to shallow
areas, and thus confidence remains too low to include visibility
reductions at any given TAF site at this time. Northwesterly
winds this afternoon are expected to remain somewhat gusty, with
speeds up to 15 knots and gusts up to 25 knots, through the
late afternoon, before diminishing overnight and turning
anticyclonically around high pressure moving in across the
forecast area through the end of the TAF period.

&&

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

&&

$$

UPDATE...Adam
DISCUSSION...NH
AVIATION...Adam