422
FXUS63 KBIS 080111
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
711 PM CST Fri Feb 7 2025

.KEY MESSAGES...

- Heavy snow with rates around 1 to 2 inches per hour will
  continue along and south of Interstate 94 through this
  evening, tapering off from west to east later tonight into
  early Saturday morning.

- Dry conditions with below normal temperatures are expected
  for the rest of the weekend.

- Arctic air returns next week, with dangerously cold wind
  chills as low as 35 to 45 below zero at times.

&&

.UPDATE...
Issued at 711 PM CST Fri Feb 7 2025

Mesoscale banding over south central North Dakota has become
less intense and more broad over the past hour or so, and has
now shifted out of southwest North Dakota. The transition of the
banding characteristics has likely resulted in a decrease of
snowfall rates for some areas (such as Bismarck/Mandan), but an
increase for others. RAP guidance continues to advertise several
more hours of mid level frontogenesis along and south of I-94
from Bismarck to Jamestown, with peak intensity around 8-9 PM
CST. No changes to the warning or advisory are needed at this
time.

In other forecast news, satellite imagery shows a large stratus
deck extending into southern Saskatchewan/Manitoba, and trends
would suggest a high probability that these clouds will mostly
remain over northern parts of the state through the night. If
this does happen, our low temperature forecast will be far too
cold. Even if there is clearing, we are skeptical of the
inherited forecast of lower to mid teens below given the nearest
teens below dewpoints are up in central Manitoba. For now, just
a slight bump in overnight temperatures was made across the
north until confidence in the clouds persisting is higher.
Because of this trend, there is also now less concern for wind
chills falling below advisory criteria levels of 30 below later
tonight.

UPDATE
Issued at 441 PM CST Fri Feb 7 2025

Radar shows a narrow band of heavy snow persisting from around
Baker, MT to Bismarck and Steele. Upstream trends suggest little
to no change in the positioning or strength of the banding over
the next few hours, and 1 to 2 inch per hour rates are being
observed under the band at our office. The Winter Storm Warning
has been expanded north into Stark, Morton, Burleigh, and Kidder
Counties. Oliver County is also now under a Winter Weather
Advisory. The 4 counties that were added to the warning are now
expected to have a narrow corridor of 5 to 7 inches of total
snow accumulation, focused over southern parts of each of those
counties.

&&

.DISCUSSION...
Issued at 235 PM CST Fri Feb 7 2025

Inverted surface trough combined with a frontal boundary and
upper level wave will continue snow to the southern half of
North Dakota today through much of tonight, and into Saturday
morning for some eastern areas. Low to mid level frontogenesis
appears to be peaking now through this evening, creating a
decent band of snow across the southern tier of counties in ND.
These counties have been upgraded to a Winter Storm Warning as
total snow accumulations of 4 to 8 inches are now expected.
Meanwhile along the Interstate 94 corridor, snow looks to have
shifted far enough north for snow accumulations of 2 to 5 inches
in these areas. Thus a Winter Weather Advisory has been issued
for counties along Interstate 94 for today into Saturday. If the
band further shifts more north then near 6 inches of snow are
possible in these areas. For now the warning remains in the
highest confidence areas. Winds look to be limited with this
system, although there is a brief window of blowing snow tonight
in central portions. Areas not in winter highlights could see at
least a slight chance of snow, although north of Highway 2
appears to be the cutoff for this slight chance. These northern
areas will start to feel the effects of a surface high and cold
northerly flow. Low temperatures in the north tonight will be in
the teens below zero, with single digits below zero south. Wind
chills along the Canadian Border tonight could be near Cold
Weather Advisory criteria especially Saturday morning. Given the
brevity of these colder wind chills will hold off on any cold
weather products at this time. Surface high moves in on Saturday
ending snow from west to east in the morning and bringing
clearing skies. Perhaps some breezy winds linger in eastern
portions through Saturday, although they look to be just low
enough to limit blowing snow impacts. Highs on Saturday will
generally be in the range of 5 to 15 degrees above zero. Surface
high is replaced by mainly dry northwest flow Saturday nigh
through Sunday. Some breezy winds may again be found on Sunday,
although look to be below advisory criteria. Cold temperatures
will continue to filter into the region with lows Saturday night
in the single digits below zero, and highs on Sunday again in
the 5 to 15 degree range. Generally light winds Saturday night
and Sunday morning should limit wind chill impacts.

Very cold temperatures then return Sunday night through much of
next week. Arctic front looks to push through Sunday night
through Monday. There could be some light snow with the passage
of this front, although NBM pops are mainly dry at this time.
The bigger concern will be the dangerously cold temperatures and
wind chills. These wind chills look to be Cold Weather Advisory
levels Sunday night through Monday (colder than 30 below).
Surface high behind the arctic front reinforces the cold air
Monday night through Tuesday. At this time this looks to be the
coldest day of the week, with air temperatures in the 20s below
zero and wind chills in the 40s below zero. Tuesday night could
see continued dangerous cold that lingers into Wednesday
morning. The rest of next week continues to look very cold with
the arctic airmass lingering across the state. Low temperatures
near 20 below zero could linger in the north with teens below
zero lingering in the south. High temperatures each day look to
remain in the single digits below zero north to the single
digits above zero south. Surface high should keep mainly dry
conditions through mid week, although moisture passing in
northwest flow aloft could bring periods of clouds at times.
Later in the week NBM returns chances for snow as warm air
advection aloft could return. This will be dependent on a
Pacific trough forming off the west coast which most clusters
have. This may not move far enough inland to bring significant
warming. This shows up in the NBM temperature trends and
spreads as only a slight warmup is being forecast by next
weekend. This is also being shown in the CPC 6 to 10 and 8 to 14
day outlooks.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 711 PM CST Fri Feb 7 2025

Heavy snow will cause IFR to LIFR visibility with MVFR ceilings
across southern North Dakota this evening, ending from west to east
later tonight into early Saturday morning. VFR conditions are
otherwise likely to prevail, but there is a small chance for low
ceilings developing across parts of western and central North
Dakota during the day Saturday. Winds will primarily be
northeast to northwest around 5 to 10 kts.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 9 AM CST Saturday for NDZ020-037.
Winter Weather Advisory until 2 AM MST Saturday for NDZ031-032.
Winter Storm Warning until 3 AM CST /2 AM MST/ Saturday for
NDZ033-040>045.
Winter Storm Warning until 9 AM CST Saturday for NDZ034>036-
046>048-050-051.

&&

$$

UPDATE...Hollan
DISCUSSION...Anglin
AVIATION...Hollan