116
FXUS63 KBIS 040503
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1203 AM CDT Sat Oct 4 2025

.KEY MESSAGES...

- Windy with high chances for rain, heavy at times, across
  southwest and central North Dakota Saturday night into Sunday,
  with medium chances for rain northwest.

- A few strong to marginally severe thunderstorms are possible
  across south central into eastern North Dakota late Saturday
  afternoon through Saturday night.

- Much cooler for the first half of next week, with highs mostly
  in the 50s and lows in the mid 20s to mid 30s.

- Medium chances for a hard freeze across much of western and
  north central North Dakota Sunday night and Monday night.

&&

.UPDATE...
Issued at 1150 PM CDT Fri Oct 3 2025

Made some minor updates to pops. Shower activity in southeast
Montana northeast into west central ND. Although quite dry with
high cloud most at or above 10kft, high enough reflectivities
that some areas could see a few sprinkles or a brief shower.
Miles City MT reported a brief shower earlier this evening with
activity currently in west central ND. Otherwise no changes
needed. Gusty southerly winds will continue south central into
the James River Valley.

UPDATE
Issued at 1049 PM CDT Fri Oct 3 2025

Light radar returns are beginning to increase from southeast
Montana to southeast Saskatchewan. Do not think much, if
anything is reaching the ground in northwest North Dakota, but
rain has just recently been reported in Estevan. It has also
been windier than expected in northwest North Dakota this
evening, likely driven by a stronger than anticipated surface
pressure gradient in the northwest quadrant of a deepening
cyclone. Short-term guidance shows the pressure gradient
relaxing through the rest of the night.

UPDATE
Issued at 749 PM CDT Fri Oct 3 2025

No major forecast changes are needed for this update. The cold front
has entered northwest North Dakota, where gusts to around 30
mph have been reported. Not expecting gusts this strong to
persist into the late evening.

&&

.DISCUSSION...
Issued at 230 PM CDT Fri Oct 3 2025

Southwesterly flow is found over the northern Plains as an
upper level trough is displaced eastward by an upper level low
moving into northern California. At the surface, analysis places
a surface low pressure center in southeastern Montana. A
pseudo- stationary front associated with this low is draped from
Bowman County up to Bottineau County. High temperatures today
remain well above normal, broadly from the upper 70s along the
International Border up to the upper 80s to lower 90s in our
southern counties. Dry conditions are expected across the far
southwest this afternoon, as relative humidity drops as low as
to around 20 percent. With fuels curing/cured across the west,
and with moderate winds from 15 to 20 MPH expected as the
surface low begins to moves into the southwest, a brief period
of near critical fire weather conditions is anticipated this
afternoon. While the strongest winds are expected to remain
further to the east of the driest conditions, an interrogation
of BUFKIT model soundings reveals at least some potential for
conditions to mix out across the southwest, in which case
stronger winds could be expected. With all of this considered,
SPC has placed portions of far southwestern North Dakota into an
elevated fire weather outlook for this afternoon.

Otherwise today, there is a low chance for isolated
thunderstorms to develop this afternoon. The convective
environment is decent, with model MUCAPE values peaking into the
1000-1750 J/KG range and bulk shear values from 35 to 45 knots.
That being said, much of this instability is elevated above a
fairly robust low level cap as warm air advection continues
through much of this afternoon and evening. Along with fairly
dry low to mid level conditions across the forecast area,
thunder is expected to be kept at a minimum today, if it ends up
developing at all.

The influence from the main upper level wave is anticipated to
increase through much of the day Saturday, lofting a cold front
across the state and displacing the previously mentioned low
pressure center through Sunday. There will be an opportunity for
some thunderstorms development Saturday afternoon and evening
as the pseudo-stationary front is pushed through eastern North
Dakota as a cold front, providing sufficient lift to get some
isolated rumbles of thunder. An interrogation of BUFKIT model
soundings reveals that a fairly significant cap is expected to
linger across the James River Valley during this period, but if
a storm manages to break through, conditions are such that a
stronger to marginally severe thunderstorm is possible. Large
hail to the size of quarters and damaging wind gusts up to 60
MPH would be the main hazards expected with any storm that does
become severe. Overall, the better convective environment
remains to the east of the forecast area. SPC continues to paint
portions of southcentral and much of eastern North Dakota in a
level 1 of 5 risk for isolated severe thunderstorms on Saturday.

Now on to the main show. Widespread stratiform showers are
anticipated to develop ahead of and along the cold front passing
through North Dakota late Saturday through Sunday. Moderate to
heavy rainfall rates can be anticipated during this period, a
strong FG forcing and a large deformation zone becomes draped
from southwestern to northeastern North Dakota. Expected
rainfall totals have remained fairly consistent over the past
few model runs, with the NBM advertising a swath of medium to
high probabilities (45 to 75 percent) for at least 1 inch of
rain stretching from Bowman County up to Pembina County.
Notably, there also a a low chance (approximately 10 percent)
for some locations to approach or exceed 2 inches of rain,
though the expectation is that these higher amounts will be tied
to any thunderstorms that do end up developing. Conditions
across western and central North Dakota are such that this
amount of rain is not anticipated to cause flooding across the
rural portions of the state, though urban areas may see some
street flooding if they fall under the heaviest rainfall rates.

Otherwise, much cooler and somewhat windy conditions are
possible on Sunday on the backside of the cold front. Ongoing
cold air advection and the development of a LLJ across central
and eastern North Dakota is expected to turn winds out of the
north northwest at 20 to 25 MPH, gusting up to 35 MPH. High
temperatures Sunday afternoon are broadly forecast in the lower
50s to lower 60s. These more seasonable temperatures are
expected to last through much of the coming week, as high
pressure bleeds in across the northern Plains. With this setup
becoming analogous to our classically cold weather days, the
axis of high pressure found over central North Dakota into the
Aberdeen area, morning low temperatures on Monday and Tuesday
are expected to become quiet chilly. With temperatures forecast
to drop into the upper 20s to lower 30s across western and
northern North Dakota, there a decent shot at a Freeze Warning
being needed both days. We will continue to evaluate the need
for these products over the next few days, as questions about
how much cloud cover lingers during this period persists at this
time. A slight warm-up back into the 60s and 70s is then
anticipated through the later half of the workweek as a
transient upper level ridge slides across the Northern Plains.
Generally dry conditions are anticipated during this period,
though a shot or two of precipitation is not out of the question
Thursday and Friday as upper level flow turns increasingly
northwesterly.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1150 PM CDT Fri Oct 3 2025

A cold front is currently situated from Rolla through Beach and
will continue to move southeast overnight. North to northwest
winds already over northwest ND. Elsewhere, southerly winds
(strong south central into the JRV) will shift northerly with
the frontal passage. Very strong winds aloft at KJMS will
necessitate a mention of LLWS through 11-12 UTC. Expect VFR
conditions overnight with isolated showers, which are too
isolated in nature to mention in any one TAF.

There is a low chance that an area of MVFR ceilings could spread
across much of western and central North Dakota tonight into
Saturday morning. Confidence in these lower ceilings developing is
not high, so have limited to a SCT mention in the TAFs for now.

Chances for rain will increase from western into central North
Dakota through the day Saturday. Periods of heavier rain could
reduce visibility at times. This may be limited to the
afternoon hours in southwest North Dakota prior to Saturday
evening, when rain is expected to become much more widespread.
A few thunderstorms could also be developing in south central
North Dakota near the end of the forecast period.

&&

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

&&

$$

UPDATE...TWH
DISCUSSION...Adam
AVIATION...TWH