311
FXUS63 KBIS 150900
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
400 AM CDT Tue Jul 15 2025

.KEY MESSAGES...

- Medium to high chances for showers and storms will continue
  this morning through late Wednesday.

- Well below normal temperatures Tuesday through Thursday, with
  near-record cold highs in the 60s Tuesday and Wednesday.

- Dry Thursday, then more chances for showers and storms through
  the end of the week.

&&

.DISCUSSION...
Issued at 400 AM CDT Tue Jul 15 2025

Near zonal flow is found aloft over the northern Plains this
morning, though is expected to become increasingly southwesterly
through the late morning and afternoon as a series of depending
shortwaves move eastward. A quasi-stational front lingers
across south central North Dakota this morning, promoting on-going
showers and a few thunderstorms across this area. This front is
expected to continue to be pushed further south through this
morning, potentially exiting to the south of the forecast area
as a cold front by the early afternoon. Showers and embedded
thunderstorms have also developed across much of northwestern
and north central North Dakota, with medium to high chances (45
to 85 percent) spreading widely across the forecast area through
the afternoon. Severe weather is generally not expected today,
though a stronger storm or two capable of producing small hail
is not impossible in the far southern James River Valley as the
aforementioned front exits to the south. On the backside of this
cold front temperatures today are much cooler than the day
before, with high temperatures forecast broadly in the 60s and
70s this afternoon. Moderate CAA across the forecast area and a
tight W-E orientated pressure gradient will help keep
northwesterly winds breezy through much of the day today, with
sustained gusts up to 20 MPH and gusts up to around 30 MPH.

With high pressure starting to build into the region out of the
southern Canadian Prairies this evening and overnight, chances
for showers and thunderstorms will start to diminish across
eastern and central North Dakota overnight into Wednesday.
Medium to high chances (40 to 70 percent) will linger across
western North Dakota as low pressure system associated with a
moderately upper level trough cuts across Wyoming and western
South Dakota. These chances are expected to expand to include
south central North Dakota as showers and storms develop along
an surface trough trailing behind the aforementioned low
pressure system. With the ongoing showers expected in the
southwest and the cooler airmass over the forecast area, high
temperatures on Wednesday are expected to be unseasonably
cooler, broadly in the 60s though portions of the southwest may
struggle to break through the upper 50s.

With high pressure settling over the northern Plains through
Wednesday afternoon, all showers and storms are expected to move
off to the south by late afternoon, early evening period. When
it`s all said and done, additional rainfall totals approaching
another 0.5 inch are possible, with the best chances (30 to 50
percent) found south of Highway 2. In the southwest, where
showers are expected to linger throughout the whole period,
there is a small chance that additional rainfall totals could
exceed 1 inch overall (~30 percent chance).

A transient upper level ridge is then expected to build in
behind the upper level trough on Thursday, helping keep
conditions dry across the forecast area and kick starting a
warming trend that will continue through the end of the week,
with highs broadly back into the 70s Thursday afternoon. A
return to near zonal flow is then favored by the ensemble,
sustaining the warming trend while reintroducing off and on
chances for showers and thunderstorms through the end of the
week. With another positively tilted upper level trough progged
to cut across the southern Canadian Prairies Thursday night
through Friday, medium to high chances (40 to 70 percent) for
showers and storms are expected. With this pattern, there is a
non-zero chance for some stronger to severe storms to develop,
though any details about potential timing and hazards is hazy
this far out. The CSU machine learning algorithm does paint a
low potential for severe weather across the southwest on
Wednesday. On the backside of this trough, generally zonal to
northwesterly flow is expected to develop as a transient upper
level ridge slides across the northern Plains, drying conditions
out somewhat for Saturday. The ensemble then diverges somewhat
at this point, with the majority of members (~80 percent)
favoring a much more quickly moving ridge, subjecting the
forecast the southwesterly flow Saturday night through Sunday,
and according an uptick in precipitation chances (30 to 50
percent) broadly across the area. CSU machine learning lightly
paint southwestern North Dakota again on Sunday with a low
potential for severe weather, which would be associated with
this pattern. This solution is the cooler of the two, with high
temperatures peaking into the 80s by Sunday. A minor cluster
also exists (~20 percent), which instead favors a much more
slowly moving upper level ridge, which would help limit PoP
chances on Sunday and the limit the potential for severe weather
even further. Additionally, this pattern would also promote the
warmest temperatures across the forecast area, with highs
peaking in the 90s. The ensemble gets increasing discordant
beyond this point, though a general agreement a slight cooling
trends through the early portions of next week is evident. The
CPC 6 to 10 day outlook reflects this, with near normal to
slightly below normal temperatures anticipated for July 20th
through the 24th.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 400 AM CDT Tue Jul 15 2025

Mainly VFR ceilings and visibilities are found at all TAF sites
at the time of this update. Scattered showers and thunderstorms
are found across southern North Dakota this early morning.
Another push of showers and storms are anticipated to move into
northwester North Dakota later this morning, though these should
generally become showers by the mid morning hours. MVFR to IFR
ceilings and visibility are anticipated if any storms manage to
move any terminal, though the confidence remains low at this
time. Thus, have generally added PROB30 groups for -TSRA for
KXWa, KBIS, and KJMS at the time of this update. A general
lowering to MVFR to IFR ceilings is anticipated through the the
early overnight period as showers fill in and become more
widespread across the forecast area. These showers will linger
through the day today and through the end of the TAF period.
Northwest winds are expected to become gusty through the
morning and afternoon, with sustained speeds up to 20 knots and
gusts up to 30 knots. Winds will then diminish through the
evening and the end of the TAF period.

&&

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

&&

$$

DISCUSSION...Adam
AVIATION...Adam