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000
FXUS63 KBIS 180608
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
108 AM CDT Thu Apr 18 2024

.KEY MESSAGES...

- Northwest winds gusting to 50 mph are expected across western
  and central North Dakota during the day Thursday.

- Chances for rain and/or snow showers through Friday, mainly
  over the northern half of the area (~30-60 percent chance).
  Greatest snow probability for an inch or more (40-60 percent
  chance) over the Turtle Mountains region.

- Mainly dry conditions expected this weekend, with temperatures
  trending warmer. Next chance of precipitation arrives Sunday
  night into Monday.

&&

.UPDATE...
Issued at 108 AM CDT Thu Apr 18 2024

We blended recent observed trends and guidance into the forecast
overnight with this update, but no significant changes resulted.
Winds have diminished from their diurnal peak late Wednesday,
but will remain elevated through the night given continued low-
level cold air advection that won`t allow the boundary layer to
fully decouple. Snow showers have also diminished in the last 2
hours, but radar trends suggest isolated to scattered coverage
will continue in the west and north overnight.

UPDATE
Issued at 947 PM CDT Wed Apr 17 2024

While there are still a few light snow showers floating around
across the northern half of the forecast area, most of this
activity has diminished with the setting of the sun. Winds have
also diminished but it will remain breezy to windy through the
night. Winds increase again tomorrow so we went ahead and
decided to issue a Wind Advisory for tomorrow from 14z to 02z
Friday across all of western and central North Dakota. Expect
sustained winds up to 35 mph and gusts to around 50 mph.
Otherwise, no major changes were needed for this update.

UPDATE
Issued at 622 PM CDT Wed Apr 17 2024

Isolated to scattered showers have developed as expected across
the northwest and north central. These showers produced some
light snow and sleet as they passed through the greater
Williston area earlier this afternoon. While some of this
activity will diminish as sunset approaches, we will continue
to hold onto low to medium rain/snow chances across the northern
third of the state given decent synoptic forcing passing
through. For this update, blended in the latest observations to
the going forecast. The Wind Advisory still looks to be in good
shape and will not make any changes at this time.

&&

.DISCUSSION...
Issued at 245 PM CDT Wed Apr 17 2024

Currently, large area of upper level low pressure centered over
far south central Canada, continues to spin over much of the
Northern Plains region. Associated surface low centered over far
southwestern Manitoba, with weak CAA west and north central, and
WAA south and southeastern areas of the state. Embedded waves
within the low continue to rotate southeast and east over
northern areas of the region, with light radar returns showing
up now in northwestern ND. Will keep a mention of
isolated/scattered showers in the forecast for this activity
through mid-evening. Winds gusting between 40-45 mph within the
advisory area, a few gusts to near 50 mph. Thus, no changes to
the wind headlines with this product issuance. It should be
noted that these winds are over-performing from what sounding
analysis earlier suggested, and will be taken into account for
Thursday.

Shower coverage should increase over the next several hours as
the aforementioned embedded waves rotate farther south into
North Dakota, with a rain/snow mix possible west and north
central where the cooler air aloft will be located and as
boundary layer temperatures drop this evening. Precipitation
will then be confined to the north overnight, closer to the
forcing of the upper low. Some light snow accumulations will be
possible across the north, especially around the Turtle
Mountain region where there is a decent chance (~60%) for an
inch by Thursday morning. Winds will also remain breezy tonight
with steady gradient forcing, but the gust potential should
diminish after 00Z as the low level inversion develops, though
still somewhat gusty with another surge of CAA spreading south
and east across North Dakota.

The upper low will slowly move east along the International
Border area through Thursday, then continues east along the
Minnesota/Canadian border into Friday. Expect another round of
showers for Thursday, again the best chances north near the
track of the embedded waves, along with windy conditions in the
wake of the cold FROPA moving through tonight. BUFKIT soundings
indicate a well mixed boundary layer across the region, upwards
to 8K feet AGL, where we could easily tap into 40-45 kts of
wind to mix down to the surface. Thus, wind headlines are likely
during the day Thursday again, and will most likely cover most
if not all of western and central ND. With ongoing headlines
today, will let the evening or mid shift issue this. Went with
a 75/25 NBM/NBM Experimental blend for winds for Thursday giving
how things developed today.

With snow showers continuing Thursday night into Friday,
additional snow accumulations will be possible across the north
through Friday morning, with NBM snow probs showing a 60-70%
chance for another inch across the Turtle Mountains, and a few
tenths elsewhere across the north. So still something to keep
an eye on over the next few forecast cycles given the strong
winds also expected. The CAA both Thursday and Friday will also
result in much below normal highs, ranging in the mid 30s to
lower 40s (normal for this time of year is right around 60F).

Once the low departs by this coming weekend, we transition back
to a northwesterly flow regime, which should result in
temperatures trending warmer and back closer to normal values
for mid/late April, especially for Sunday when a S/WV ridge and
warm frontal zone develops west to east across the region.
Mainly dry this weekend, with precipitation chances returning
late this weekend into Monday as strong S/WV/clipper system is
depicted to push southeast through the area. Will also see an
uptick in winds with this wave on Monday, though temperatures
remain in the 50s for highs.

Broad ridging follows, with high temperatures rebounding back
into the 60s by mid-week.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 108 AM CDT Thu Apr 18 2024

Low VFR to MVFR ceilings are expanding over northern ND as of 06
UTC and are forecast to impact KMOT, KXWA, and eventually KJMS
through midday Thursday. The southern and western extent of the
MVFR ceilings is more uncertain, with only 30 percent chances of
them impacting KBIS or KDIK. West-northwest winds will gust to
around 30 kt overnight, then increase again Thursday with gusts
up to 40 kt across all of western and central ND. Isolated to
scattered snow showers are also expected, especially Thursday
afternoon, with 20 to 30 percent chances of them impacting any
given terminal, highest from KXWA to KMOT.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 9 AM CDT /8 AM MDT/ this morning to 9 PM
CDT /8 PM MDT/ this evening for NDZ001>005-009>013-017>023-025-
031>037-040>048-050-051.

&&

$$

UPDATE...CJS
DISCUSSION...NH
AVIATION...CJS