607
FXUS63 KBIS 011528
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
928 AM CST Sun Nov 1 2026

.KEY MESSAGES...

- Dense fog, mist, and patchy drizzle across much of North
  Dakota this morning.

- Rain will fall across most of the state tonight through Monday
  night. There are medium to high chances for 1 to 2 inches of
  rain across much of southwest and south central North Dakota.

- Near to above average temperatures and drier weather are
  favored mid to late next week.

&&

.UPDATE...
Issued at 926 AM CST Sun Nov 1 2026

Visibility in fog has been a bit slow to improve so far this
morning, so have extended the Dense Fog Advisory until noon CST.
Otherwise, remainder of forecast continues to be in good shape.

UPDATE
Issued at 631 AM CST Sun Nov 1 2026

Fog has lifted across much of south central North Dakota, but a
few webcams continue to show dense fog along and just to the
west of the James River Valley. The Dense Fog Advisory was
extended until 9 AM CST for Eddy through Dickey Counties,
matching the expiration time for western and north central North
Dakota. The rest of the advisory in south central North Dakota
was allowed to expire on time at 6 AM CST. It is not currently
that foggy in Oliver, Mercer, McLean, and Sheridan Counties,
but guidance does show potential for fog to redevelop there
over the next couple hours.

&&

.DISCUSSION...
Issued at 417 AM CST Sun Nov 1 2026

A deep trough lies along the Pacific Coast early this morning,
placing the Northern Plains under southwest flow. Surface and
low level flow broadly remain southeast to southerly between
high pressure over the eastern Great Lakes and low pressure near
the Northern Rockies. Unseasonably high dewpoints within the
persistent return flow continue to support dense fog across much
of western and central North Dakota. South central North Dakota
is an exception to this, at least temporarily. Consensus
visibility guidance does lift the fog northward east of the
Missouri River through early/mid morning, but also shows some
redevelopment on a more widely scattered basis. Therefore, will
allow the current Dense Fog Advisories to remain in place, with
expiration times of 6 AM CST south central and James River
Valley, and 9 AM CST elsewhere. Fog may be slower to lift in
western North Dakota, but visibility should improve at most
locations by early afternoon. An overcast sky will still prevail
through the daytime hours, with a small chance of sunshine
peeking through the clouds in the southwest. High temperatures
today should be a few degrees warmer at most locations, with
mostly mid 50s to lower 60s expected.

The western trough will approach the Rockies tonight, inducing
lee cyclogenesis in northeast Colorado. The surface low is
forecast to quickly lift northeast into South Dakota/Nebraska on
Monday, then stall and slowly drift eastward over the Missouri
River Valley late Monday into Tuesday. Meanwhile, the parent 700
mb low is forecast to spin from western Wyoming tonight into
South Dakota on Monday. All this sets the stage for a widespread
rainfall event over much of North Dakota, but especially the
southern half of the state, tonight through Monday night. Both
HREF and REFS probability-matched mean QPF through Monday
afternoon, which covers most but not all of the rainfall, places
at least 0.5" for most areas south of Highway 2, at least 1"
from around Beach to Harvey and southward (except a corridor
from Dickinson to Bowman), and at least 2" over much of the
southern James River Valley where strong frontogenesis
underneath Q-vector convergence is forecast to produce
mesoscale banding. Rain will quickly spread northeastward across
the state this evening through tonight and gradually taper off
from northwest to southeast Monday afternoon through Monday
night. Some lighter rain could linger in far south central to
southeast North Dakota on Tuesday, but most of the day will be
dry. Temperatures will remain above freezing through the
duration of precipitation, with little diurnal variation. Lows
tonight are forecast in the lower 40s to lower 50s, with highs
on Monday in the mid 40s to mid 50s. Depending on how quickly
cloud cover departs, parts of western North Dakota could fall
below freezing Monday night. But underneath clouds and for sure
where precipitation continues, Monday night temperatures will
remain above freezing. Lastly, the strengthening surface
pressure gradient will cause windy conditions Monday into Monday
night. However, model soundings reveal that a lack of diurnal
mixing of the boundary layer due to extensive cloud cover could
greatly inhibit momentum transfer of 35-45 kt low level winds.
It still may be windy enough for an advisory in southwest and
perhaps south central North Dakota Monday afternoon and evening,
but this may be driven more by sustained winds around 30-35 mph
rather than gusts over 45 mph.

Surface high pressure is forecast to slide into the Northern
Plains Tuesday into Wednesday under a pseudo omega blocking
pattern that places the upper level high over eastern Montana.
This should lead to a period of drier weather with similar
daytime highs that are near to slightly above average but cooler
overnight lows that are still near to above average but below
freezing. The NBM maintains these temperature trends through
the end of the week when ensembles show greater spread in how
quickly the upper ridge could break down.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 631 AM CST Sun Nov 1 2026

LIFR to IFR ceilings cover most of western and central North
Dakota early this morning, and are likely to fill back in over
south central parts of the state by around sunrise. Dense fog,
mist, and patchy drizzle will also continue across western and
north central North Dakota this morning, with conditions
improving this afternoon. Ceilings are forecast to lift to MVFR
this afternoon before falling back to IFR/LIFR later tonight.
Rain will begin moving into to southwest North Dakota this
evening and spread across most of the state by the end of the
forecast period. MVFR to IFR visibility can be expected with the
rain. Winds will generally be southeast to south around 5-10
kts today, increasing to near 15 kts at KJMS this afternoon, and
turning to the east and northeast this evening through tonight.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until noon CST /11 AM MST/ today for
NDZ001>005-009-010-012-013-017>020-022-023-025-031>033-037-040-
041-043-044-048-051-055>058.

&&

$$

UPDATE...JJS
DISCUSSION...Hollan
AVIATION...Hollan