353
FXUS63 KBIS 171659
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1159 AM CDT Wed Sep 17 2025

.KEY MESSAGES...

- Showers and isolated thunderstorms remain in the forecast
  through Friday. The highest chances are through this morning
  south central, then again late tonight through Thursday where
  much of the forecast area has a 70 to 90 percent chances of
  showers and a few thunderstorms.

- Cooler, but still seasonable temperatures are on tap to
  finish out the second half of the week.

&&

.UPDATE...
Issued at 1153 AM CDT Wed Sep 17 2025

A persistent area of showers with isolated embedded thunder
remains over far south central ND. This area has shown an
overall downward trend in intensity over the past couple hours.
Especially with the intensity of thunderstorm activity, which
remains confined mainly to the Emmons county. Upward motion
responsible for this activity is expected to diminish this
afternoon, although as waves of 70H UVV rotate around the main
circulation over South Dakota, additional showers with embedded
thunder can not be ruled out over the south central this
afternoon. Elsewhere, to the north and west, where we do see a
bit more instability, we can not rule out an afternoon
thunderstorm. Highest instability currently extends from
southwest ND into northwest/north central ND. Little if any
shear is in place, so the threat for severe weather remains low.
Will monitor the non-severe tornado parameter as this area
heats up early this afternoon. With another mid-upper level
circulation over NE Montana into southwest SK, a funnel or non-
supercell tornado threat can not be ruled out this afternoon
where we see some sunshine.

UPDATE
Issued at 946 AM CDT Wed Sep 17 2025

Minor updates for area of showers and thunderstorms over the
southwest and south central where slow moving convection
remain. Also, showers and a few thunderstorms have developed
over the north central portion of the state as well. Updated
text products will be transmitted shortly.

UPDATE
Issued at 547 AM CDT Wed Sep 17 2025

The main update early this morning is that showers and a few
thunderstorms have developed over much of the southwest and
parts of the south central over the past couple hours. Most
thunderstorms so far have been confined to a low instability
gradient from approximately Dickinson to Hazen to Washburn. As
forecast, fog has developed over parts of northern ND, however,
appears to remain very patchy in nature at this time.

&&

.DISCUSSION...
Issued at 249 AM CDT Wed Sep 17 2025

A fairly well stacked low pressure system will continue to
organize over the Central Plains today before gradually churning
into the Northern Plains tonight through Thursday, and lingering
through Friday. This will bring numerous showers and isolated
thunderstorms to the state today through Friday. Currently, most
showers and thunderstorms are still down in Nebraska and
western Iowa. However, northern periphery showers off an
associated surface trough are present in northwestern South
Dakota. While this is delayed from model runs in prior days,
these will gradually work into the state today with additional
development also expected.

Through the duration of this system, instability is generally
expected to be fairly minimal, except for in the areas along,
south, and west of the Missouri River this afternoon. But even
then, little shear is is progged. So while occasional
thunderstorms are expected, especially in the southwest this
afternoon, strong to severe storms are not anticipated. The
highest chances for widespread showers, and maybe a few rumbles
of thunder, is late tonight through the day Thursday, where
most of the forecast area will see a 70 to 90 percent chance of
precipitation. The lowest overall chances for precipitation
during this event will be west near the ND/MT border.

Once this system clears out, mostly dry conditions are expected
for this weekend through the middle of next week. That said,
deterministic models are fairly consistent in bringing a trough
through late this weekend or Monday morning. While the NBM
currently keeps conditions dry throughout the CWA, wouldn`t be
surprised if at least a few showers occur in the end. By the
middle of next week, the pattern becomes less certain, though
an incoming ridge seems favored despite some models maintaining
a more zonal flow pattern.

With periodic precipitation chances and ample cloud cover, much
cooler temperatures are expected today through Friday with
highs mostly in the 60s to low 70s. Thursday will be the coolest
day, however, with temperatures forecast to range from the
upper 50s to upper 60s. A slight warming trend is then favored
this weekend and into early next week with highs returning into
the 70s to around 80. Lows will be mostly in the upper 40s to
mid 50s through at least this weekend, which is seasonable for
this time of year. As a final note, a little patchy fog has
begun to develop in northern parts of the state early this
morning and should dissipate by late morning.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 1153 AM CDT Wed Sep 17 2025

Showers and isolated thunderstorms remain over south central
ND. Isolated showers and thunderstorms are possible this
afternoon across the remainder of western and central ND as
well, although besides the current activity around KBIS, will
not include a mention of thunder at this time. Late tonight into
Thursday will bring another round of showers, with a low
potential for thunder. Expect widespread MVFR-IFR visibilities
and ceilings in occasional rain and areas of fog continuing
through Thursday morning. Expect an east to northeast surface
flow of 5 to 15 knots through the forecast period.

&&

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

&&

$$

UPDATE...TWH
DISCUSSION...Telken
AVIATION...Telken