National Weather Service Raw Text Product

497 
FXUS63 KBIS 181837
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1237 PM CST Tue Jan 18 2022

.UPDATE...
Issued at 1237 PM CST Tue Jan 18 2022

As of 18 UTC, the pressure rise maxima continues surging through
central ND, and while it has decreased a bit (to ~7 mb/3 hours),
the isallobaric response to this feature continues to generate
wind gusts near 50 kt. The peak gusts aren't lasting long enough
for us to switch wind headlines to a High Wind Warning, though we
will continue to monitor that. Gusts to 40 kt in the wake of that
pressure rise maxima continue over the rest of the area, as does
blowing snow north and east. Web camera trends suggest the lowest
visibilities are more variable than ASOS/AWOS sensors alone would
suggest, while satellite imagery suggests the most significant
blowing snow is related to well-defined plumes that are occurring
in Horizontal Convective Roles (HCRs). For the most part, those
HCRs are relatively widely-spaced, leading to the variability in
visibilities spatially, and temporally as the HCRs shift slightly
with the background flow. Satellite imagery does suggest the most
widespread blowing snow plumes are centered over Burke County and
vicinity, where impacts are likely most significant. In the end, 
we continue to monitor trends for the need for any Blizzard 
Warning upgrades, but are holding off for now. Changes with this 
update cycle were mainly focused on observational trends through 
the afternoon hours, with no significant adjustments.

UPDATE Issued at 1131 AM CST Tue Jan 18 2022

Quick update to add Divide County into the Winter Weather Advisory
given satellite imagery suggesting significant blowing snow 
continuing from eastern parts of the county upstream into southern
Canada.

UPDATE Issued at 948 AM CST Tue Jan 18 2022

Given observed visibilities of 1/2SM or less per ASOS/AWOS and web
camera trends from Portal to Minot and Denhoff, we expanded the 
Winter Weather Advisory a row of counties to the west, replacing
the Wind Advisory for that row of counties, as well. Very strong
surface pressure rises on the order of 10 mb/3 hours are surging
through the area behind the Arctic cold front, and snow showers
are ongoing in the post-frontal environment too where the stratus
deck is in the dendritic growth zone. Given the strength of the
winds and temperatures that were only marginally above freezing
the last few days in parts of north central and east central ND,
it's possible any crust that formed on the snowpack from Portal
to Minot and Jamestown has or will be broken, and so we will need
to monitor the longevity of low visibilities in case an upgrade to
Blizzard Warning becomes necessary. We also will likely reach High
Wind Warning Criteria in some areas, but again the longevity of
60+ mph gusts may be too short-lived to upgrade the wind headline.

UPDATE Issued at 545 AM CST Tue Jan 18 2022

Near-term PoPs, sky cover, and temperatures were all tweaked a bit
with this update with the arrival of the cold front to the
northwestern corner of the state. Temperatures have warmed up 
considerably ahead of the front (leading warm front moving west to
east across the state) with the Bismarck ASOS currently reporting
40F, so this required some adjustments. Both Williston and Crosby
reported gusts/sustained winds in the 40 mph range with the
arrival of the front, and this should be expected with the leading
edge of the front as it continues to quickly advance southeast.
Lastly, a few flurries/mist will be possible under the low status
behind the front, but accumulations (if any) will be very minimal.

&&

.SHORT TERM...(Today and tonight)
Issued at 256 AM CST Tue Jan 18 2022

An active day for is in store today with an arctic front moving
into the area resulting in both wind and winter weather headlines. 

As of this writing a strong surface low is moving into
northwestern North Dakota from southeastern Saskatchewan with 
strong northwesterly winds and colder air following closely 
behind. The center of the low is expected to quickly move at an 
east- southeasterly trajectory through the state over the next 
several hours, crossing into Minnesota by mid-morning. Strong 
pressure rises associated with the arctic airmass moving in will 
occur across western and central North Dakota through the late 
morning and early afternoon. This is expected to result in strong 
winds producing gusts up to 50 mph across much of the area. 
Additionally, these winds are expected to result in areas of 
blowing snow where fresh snow has recently fallen, likely 
significantly reducing visibilities at times across the open 
country from the north central through the James River Valley. 
Much of the snow associated with this system will remain off to 
our east, but some light snow showers cannot be completely ruled 
out as the cold air pushes in. Winds are then expected to 
gradually diminish from west to east later this evening, though 
still remaining somewhat breezy through tonight, especially east.

These winds in combination with the arctic airmass moving in will
result in frigid wind chills by as early as this afternoon across
the northern tier of counties. No changes are planned to the 
current headlines in place as they cover all of the forecasted 
hazards well, but they will need to be replaced with wind chill 
headlines once the wind and blowing snow threat diminishes later 
today. Low temperatures tonight are expected to range from 5 below
far southwest to near 20 below north, though the winds will make 
it feel as cold as -40 in some locations north and east of the 
Missouri River.

.LONG TERM...(Wednesday through Monday)
Issued at 256 AM CST Tue Jan 18 2022

The colder air will linger through Thursday morning, with
dangerously cold wind chills expected across much of the area Wednesday
night into Thursday morning. Temperatures are then expected to
quickly warm into Friday as brief upper level ridging moves across
the northern Plains. An upper shortwave trough is expected to move
in behind this ridging, with widespread snow chances developing
out ahead over western and central North Dakota Thursday night 
into Friday morning. Due to this system being quick-moving, only 
light snowfall totals are forecasted at this time. 

There is a noticeable amount of uncertainty with the forecast 
beyond Friday, especially with the temperature forecast, as 
indicated by significant spread between the NBM's 25th and 75th 
percentiles. After the shortwave trough on Friday moves through, 
both the GFS and ECMWF ensemble means show strong northwesterly 
flow setting up across central Canada and into the Midwestern 
U.S. The northwesterly flow will allow for occasional slight 
precipitation chances, but the uncertainty with the temperature 
forecast appears to be due to North Dakota lying directly in the 
middle of ridge near the U.S. west coast and a deep upper low 
northeast of Ontario. Whichever of these two features ends up 
being stronger or closer in proximity to North Dakota will have a 
strong influence in our temperatures through the weekend and into 
next week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1237 PM CST Tue Jan 18 2022

Very strong winds today with reduced visibilities in blowing 
snow.

Strong northwest winds with gusts to around 50 knots will continue 
through the afternoon at KMOT, KBIS, and KJMS, and then slowly 
subside this evening. Northwest winds at KXWA and KDIK gusting to 
around 35 knots early, should slowly subside through the 
afternoon. 

Visibilities will be lowest (IFR to LIFR) at KMOT and KJMS through 
the afternoon. Mainly VFR to some patchy MVFR possible at KXWA KDIK 
and KBIS.

Strong northwest winds producing widespread blowing snow across 
portions of northern and eastern North Dakota as low pressure over 
northern Minnesota tracks slowly east. Arctic air spilling over the 
state behind the system will produce areas of MVFR ceilings tonight. 
Confidence in exactly where cigs will end up remains low, for now 
kept some MVFR cigs around through around 06 UTC and then trended to 
scattered thereafter.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 9 PM CST /8 PM MST/ this evening for NDZ019-
020-034-035-042-045>047-050.

Wind Advisory until 6 PM CST /5 PM MST/ this evening for NDZ009-
017-018-031>033-040-041-043-044.

Winter Weather Advisory until 9 PM CST this evening for 
NDZ001>005-010>013-021>023-025-036-037-048-051.

&&

$$

UPDATE...CJS
SHORT TERM...Gale
LONG TERM...Gale
AVIATION...TWH