420
FXUS63 KBIS 051940
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
240 PM CDT Sun Oct 5 2025

.KEY MESSAGES...

- North to northwest winds with gusts up to 40 MPH through the
  afternoon today.

- Widespread low temperatures at or below freezing across
  western and central North Dakota tonight. Freezing
  temperatures are possible again Monday night.

- Dry with below average temperatures continue for the first
  half of the week, with highs mostly in the 50s. A slight warm-
  up with highs in the 60s and 70s is then anticipated to close
  out the workweek.

&&

.DISCUSSION...
Issued at 240 PM CDT Sun Oct 5 2025

Flow over the northern Plains is transitioning from near zonal
to northwesterly as an upper level trough exits into the Great
Lakes region. With surface high pressure moving in northwest
North Dakota this afternoon, stratiform showers and thick cloud
cover from earlier this morning have quickly diminished from
west to east. That being said, a weak surface trough is
anticipated to be lofted through the James River Valley area
this afternoon and evening ahead of the aforementioned high
pressure center, which could results some isolated showers.
Though CAPE is a fairly limited quality during this period,
model values around 100-150 J/KG during this period and a weak
LLJ could allow for an isolated rumble of thunder or two. The
chance for severe weather is very low. With the much cooler
airmass settling over the area this afternoon, high temperatures
are expected to be near to slightly below seasonable normals,
from the mid to the upper 50s, though portions of the southern
James River Valley will peak into the lower to mid 60s.
Otherwise, moderate north to northwest winds with gusts from 35
to 40 MPH are expected through the afternoon as CAA and a strong
pressure gradient moves across the northern Plains.

With clearing skies and high pressure settling into our classic
cold weather pattern - with the axis of high pressure found
over central North Dakota down into the Aberdeen area - low
temperatures tonight are expected to drop down to near or below
freezing across much of the forecast area. NBM probabilities for
32F or less remain highest (70 to 90 percent) across the north
and in the valleys of the Chateau in the southwest, with
portions of south central North Dakota peaking in the 40 to 60
percent range. Portions of the southern James River Valley may
struggle to reach freezing tonight if northwest winds remain
elevated, but with how quickly skies are already clearing this
afternoon we would expected at least the low-lying to drop that
low. Thus, we have opted to issue a Freeze Warning across all of
western and central North Dakota for tonight.

A cool, dry pattern is then anticipated for the
first half of the week. With high pressure lingering at the
surface, and with clear skies above high temperatures both
Monday and Tuesday are expected to remain in the 50s to lower
60s across the forecast area. Through the classic cold weather
pattern is expected to start breaking down through the day
Monday, portions of northern and western North Dakota are
anticipated to drop to or slightly below freezing Tuesday
morning. A transient upper level ridge is progged to then move
through the northern Plains late Tuesday through Wednesday,
allowing a slight warm-up back in to the 60s and 70s for the
later half of the workweek. While dry conditions persist through
much of the workweek, weak shortwaves ejecting off of a Pacific
Low off the coast of Washington could allow for isolated
showers Friday and Saturday. The NBM then starts to advertise
more widespread low to medium chances for precipitation (20 to
40 percent) Sunday through early next week as the aforementioned
low moves inland and toward the southern Canadian Prairies. An
interrogation of ensemble clusters reveals this scenario to have
only a slight majority with approximately 60 percent of model
members. A comparably dry solution also exists as a minority of
members (approximately 40 percent) instead favors this Pacific
low being absorbed into broad zonal flow due to stronger ridging
across the desert southwest, keeping showers much more isolated
and mainly in eastern North Dakota on Sunday.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 240 PM CDT Sun Oct 5 2025

Some MVFR ceilings linger over south central North Dakota to
begin the 18Z TAF period. Once these clear to the east over the
next hour or two, VFR ceilings and visibility is anticipated at
all terminals throughout the TAF period. Strong north to
northwest winds are anticipated to linger through the early
afternoon, especially in central North Dakota into the James
River Valley, where speeds up to 25 MPH and gusts up to 40 knots
are expected. Winds are then anticipated to diminish through
the late afternoon and early evening, becoming light and
somewhat variable overnight. Winds are anticipated to
strengthen and reorganize out of the east southeast late Monday
morning through the end of the TAF period.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Freeze Warning from midnight CDT /11 PM MDT/ tonight to 10 AM
CDT /9 AM MDT/ Monday for NDZ001>005-009>013-017>023-025-
031>037-040>048-050-051.

&&

$$

DISCUSSION...Adam
AVIATION...Adam