718
FXUS63 KBIS 041152
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
652 AM CDT Fri Apr 4 2025

.KEY MESSAGES...

- A band of moderate to heavy snow will move through south
  central North Dakota and the James River Valley this morning.
  Total accumulations around 2 to 5 inches are expected, with a
  low probability of a narrow band of up to 7 inches.

- Below normal temperatures for most areas through Monday, then
  warming to above normal for the second half of next week.

- After today, mostly dry weather is expected through next week.

&&

.UPDATE...
Issued at 649 AM CDT Fri Apr 4 2025

Burleigh and Sheridan Counties have been removed from the Winter
Weather Advisory.

Some fog has developed in parts of southwest North Dakota,
especially along the I-94 in Golden Valley County. Otherwise, the
forecast remains on track.

UPDATE
Issued at 555 AM CDT Fri Apr 4 2025

McLean, Oliver, and Morton Counties have been removed from the
Winter Weather Advisory. The snow continues to track eastward,
with the heaviest rates implied from radar now more narrow and
located from around Fort Yates to Jamestown at the time of this
writing. Meanwhile, convective-type precipitation is increasing
over LaMoure and Dickey Counties. A webcam near Gackle
(southwest of Jamestown) suggests some freezing rain could be
mixing with snow. Think any liquid precipitation will be short-
lived, but elevated surfaces could become slick very quickly.

A clearing sky in northwest parts of the state has allowed
temperatures to plummet early this morning. Several locations in
Williams, Mountrail, and McKenzie Counties have reported minimum
temperatures in the single digits above zero.

&&

.DISCUSSION...
Issued at 405 AM CDT Fri Apr 4 2025

A series of shortwave troughs is crossing the Northern Plains this
morning. The northern stream wave propagating eastward through North
Dakota has maintained a band of snow with heavy rates along the
Highway 200 to Interstate 94 corridors as it moves through an
environment with steep mid level lapse rates and negative EPV above
strong low level frontogenesis. The heaviest snow is only lasting
around 1 to 3 hours at any given location, but rates are expected to
be as high as 1 to 2 inches per hour. A Winter Weather Advisory
remains in effect for central parts of the state this morning. To
the south of the interstate, the low level thermal profile is
slightly warmer, resulting in more of a rain/snow mix as well as
lower snow-to-liquid ratios where snow is falling. Meanwhile, the
southern stream wave has induced surface cyclogenesis over South
Dakota, and its northeastward propagation will soon cause it to
interact with the northern stream wave. This interaction could cause
a longer duration of rain/snow over the southern James River Valley
later this morning, though the intensity of the low level
frontogenesis is forecast to wane along with mid level lapse rates
weakening. The precipitation should exit our forecast area this
afternoon.

A cooler and drier air mass advecting into the region will keep high
temperatures in the 30s this afternoon. Despite the limited
atmospheric moisture, a 700 mb wave dropping down from Saskatchewan
could combine with a well mixed boundary layer to produce isolated
to scattered rain/snow/graupel/sleet showers across western parts of
the state this afternoon. Little to no impacts are expected at this
time. For tonight, surface high pressure is forecast to expand from
the Northern Rockies into Northern Plains. This could allow
overnight temperatures to drop into the teens, especially anywhere
fresh snowfall does not fully melt today. There is a low probability
for fog formation late tonight into Saturday morning, but confidence
in coverage and location is not yet high enough to add to the
forecast.

Broad surface ridging and northwest flow aloft are forecast to
remain over the region through the weekend. Saturday will be warmer
than today, but still below normal with highs in the upper 30s east
to lower 50s far west. Northwest flow patterns at this time of year
are apt to produce diurnally-driven afternoon showers, but this
potential looks to be inhibited by a lack of atmospheric moisture on
Saturday and a capping inversion on Sunday. A backdoor cold front is
forecast to plunge into the Red and Upper Mississippi River Valleys
on Sunday as a shortwave rotating around a Hudson Bay low digs into
the western Great Lakes region. The baroclinic zone is forecast to
stall in the western half of the Dakotas as it pushes up against
stout upstream ridging. This will produce a 24 to 36 hour period of
well below normal temperatures for the eastern half of the state,
although latest guidance is not showing quite as cold minimum
temperatures as before. Nevertheless, lows on Sunday and Monday
nights are forecast to fall into the teens in the east. Highs on
Monday could struggle to climb above freezing in the eastern half of
the state, but could rise above 50 in the far southwest.

The upstream ridge is forecast to shift into the Northern High
Plains late Monday into Tuesday, but it looks to quickly be squashed
by a series of Pacific shortwave troughs. There is still high
confidence that temperatures will become relatively warmer by the
second half of next week, and even the 25th percentile of the NBM
distribution brings high temperatures into the 60s. But the favored
synoptic pattern is not a slam dunk for highly anomalous warmth, at
least until next weekend when there are signs of an upper ridge
returning to the central CONUS. The lead Pacific shortwave brings a
10 to 30 percent chance of rain across the state Tuesday through
Wednesday, though amounts look to be very light. The NBM maintains a
dry forecast for the rest of the long term period, but would not be
surprised to see low chances of rain added in future forecasts given
the expected pattern. Can also envision a low chance for a few weak
thunderstorms materializing at some point next week. On a final
note, the NBM is advertising breezy conditions next week, which
paired with the warmup could prompt some fire weather concerns,
though no day in particular stands out as being critical at this
time.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 649 AM CDT Fri Apr 4 2025

Moderate to heavy snow will continue to impact KJMS and surrounding
areas this morning, with MVFR/IFR ceilings and IFR/LIFR visibility.
The snow should move off to the east by the afternoon. Elsewhere,
IFR to LIFR ceilings have settled over parts of southwest North
Dakota early this morning, including at KDIK. Think this will be
short-lived, with improvement to VFR anticipated by late morning.
VFR conditions should otherwise prevail. A few isolated snow showers
could develop across western parts of the state this afternoon, but
the probability of any terminal being impacted is less than 20
percent. Diurnal cumulus clouds at 5,000 to 10,000 feet will give
way to a mostly clear sky tonight. North to northwest winds could be
gusty at times throughout the day.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 1 PM CDT this afternoon for
NDZ023-025-036-037.

&&

$$

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