544
FXUS63 KBIS 051758
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1158 AM CST Wed Feb 5 2025

.KEY MESSAGES...

- Today another round of snow is expected this afternoon and
  evening (60 percent).

- Breezy northwest winds may lead to areas of blowing snow
  across much of the north and east late tonight through
  Thursday.

- Below average temperatures continue through the remainder of
  the week through the weekend. Dangerous wind chills Thursday
  morning.

- A third round of snow is likely (80%) Friday into Saturday,
  mainly in the south.

&&

.UPDATE...
Issued at 1150 AM CST Wed Feb 5 2025

We have started to see some sporadic light snow/flurries across
portions of the west so we decided to go ahead and expand
precipitation chances to better reflect these observations.
Otherwise, no major changes were needed for this update.

UPDATE
Issued at 932 AM CST Wed Feb 5 2025

No major changes were needed for this update. Just blended in
the latest observations to the going forecast.

UPDATE
Issued at 600 AM CST Wed Feb 5 2025

Low clouds in the northwest started producing snow, so we
updated PoPs for the next 3 hours to reflect that. Otherwise
the forecast for today remains on track.

&&

.DISCUSSION...
Issued at 205 AM CST Wed Feb 5 2025

Currently the ridge is moving in aloft, this is pushing all the
snow to fall in Canada. Winds are also light from a higher
pressure at the surface. Today will be a tad warmer with this
ridge aloft. Temperatures in the teens and 20s in the south,
the north will remain colder with highs around 7.

The second round of snow will move through today. As the ridge
axis moves through the state early this morning, southwest flow
will dominate. In this flow, little short waves will form off
the Rockies, one of the stronger, deeper ones will move through
this afternoon. At the surface an associated low pressure will
move through Nebraska. The snow will move west to east across
the state along a north/south inverted surface trough. Timing
looks to be around 2pm CT when the trough hits, there are low
(30%) chances for snow before then. Wrap around moisture on the
surface low will also create low (25%) chances of snow in the
James River Vally area through this time period. There is a very
low chance of some freezing rain along the South Dakota border
as well with some warmer air off the surface. After 9PM CT the
snow should move out of our area, this is where the next event
starts. Breezy winds will start overnight and last through
sunset Thursday. This may create some areas of blowing and
drifting snow, especially along the Coteau and east. Depending
on snowfall today this will determine how big of a concern this
will be.

So let`s talk about snowfall. Most of the snow will fall north
of the Interstate, up to the Canadian border. It looks like 1 to
2 inches may fall. The snow is more focused in the northwest
where the better forcing lays. Probabilities of at least 2 are:
Crosby: 45%
Williston: 40%
Watford City: 10%
Minot: 20%
Rugby: 20%

After this shortwave and low pressure move through Wednesday
night, the flow aloft on the backside turns slightly northwest.
Allowing colder air to filter back down into North Dakota. High
temperatures Thursday will only dip a few degrees, but again it
will be breezy. Wind chill values therefore will likely be 30
to 40 below zero during the first half of the day Thursday. So
we will likely be putting out a Cold Weather Advisory today at
some point.

Our third chance of snow will occur Friday into Saturday.
Another wave and low pressure forming off the Rockies will move
east, this time further north. We have some confidence in the
location since models have had it along the Dakota borders the
past few days. The uncertainty lays in the snow amount and if it
will be a banded snow event. The current NBM probabilities for
at least 6 inches (warning criteria) is only 10 percent. Snow
amounts have flipped flopped twice in the last 36 hours. Going
low to high back to low, and now higher in our gridded data
base. So either the NBM has not caught on to the recent changes
in the big models or WPC is using higher QPF than the NBM has.
So watch for the changes in this snow forecast. Temperatures
through the weekend will remain below average with northwesterly
flow.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1150 AM CST Wed Feb 5 2025

A fast moving system will bring light snow to the state through
this evening. Additionally, widespread MVFR ceilings will
accompany this snow, spreading from west to east. It still may
be a few hours before KJMS sees MVFR categories. Areas that see
heavier snow (mostly likely north) may also lead to brief IFR
visibilities. Snow will move out to the east by early evening
and ceilings will lift into VFR categories overnight. West to
northwest winds will also start to increase overnight, becoming
breezy by the end of the period.

&&

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

&&

$$

UPDATE...ZH
DISCUSSION...Smith
AVIATION...ZH