920 
FXUS63 KBIS 120719
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
119 AM CST Sat Feb 12 2022

.UPDATE...
Issued at 114 AM CST Sat Feb 12 2022

Expanded the mention of flurries early this morning to encompass
most of western and central ND based on radar and surface 
observations. Otherwise, the forecast remains in good shape for
this morning. 

UPDATE Issued at 1005 PM CST Fri Feb 11 2022

Numerous observations and webcams show light snow/flurries falling
from a large deck of stratus clouds across much of western North 
Dakota. Further west, eastern Montana radar imagery suggests 
slightly more robust snow showers along a low level baroclinic 
zone, underneath the left exit region of an upper level jet. In 
response, we have ramped up mentioning of light snow/flurries 
through the night. Little to no accumulation is expected at this 
time.

00Z guidance is fairly consistent with a few hundredths of an inch
of liquid across central North Dakota and into the James River
Valley on Saturday. A quick analysis of model soundings suggests 
NBM snow ratios around 15:1 may be too low, as the saturated 
portion of the thermal profile mostly resides below -12 C. We gave
a slight boost to snow ratios for this update, which resulted in 
widespread snow amounts around one half inch. Snow ratios may need
to be increased more with future updates, but the expected 
impacts remain very low to none.

UPDATE Issued at 610 PM CST Fri Feb 11 2022

Some minor adjustments were made to PoPs both tonight and
tomorrow, most notably expanding the areal coverage for the chance
of light snow along and east of Highway 83 tomorrow afternoon. But
the overall forecast thinking and messaging remain the same. Also
decreased sky cover across central North Dakota this evening to
better match the clear sky observed by satellite.

&&

.SHORT TERM...(This evening through Saturday)
Issued at 126 PM CST Fri Feb 11 2022

Wind chills and small precipitation chances highlight the short
term forecast period.

A northwest upper level flow will remain through the short term
period with periodic shots of light snow.

Currently, strong low pressure is exiting the region while cold
high pressure builds over the area from southern Canada. Snow 
showers have been rather persistent from central/eastern Montana 
into western South Dakota. Later tonight as a cold front works 
it's way back to the east towards North Dakota, there may be a 
chance of light snow over far southwest ND. Overnight lows tonight
will vary quite a bit, from the teens below zero under mainly 
clear skies and cold high pressure in the east, to the teens above
zero, with increasing clouds southwest. Temperatures will be 
steady or rising through a good portion of the night west, and 
then mainly after midnight central.

With our cold temperatures, we have already extended the wind
chill advisory to cover much of central ND east of the Highway 83
corridor, through mid morning Saturday. Depending on how we cool
down tonight and how quickly we warm up late tonight into
Saturday, portions of the advisory may need to be expanded west 
early and/or chopped off early on Saturday morning, but we have a
good start anyway.

On Saturday, the warm front moves into central North Dakota. The
warm advection, combined with a shortwave impulse moving through
the building upper ridge will produce some light snow mainly
across central North Dakota. At this time accumulations look to be
light, generally under a half inch, with many areas only seeing 
trace amounts.

.LONG TERM...(Saturday night through Friday)
Issued at 126 PM CST Fri Feb 11 2022

The northwest flow pattern continues through early next week, then 
transitions to a split flow pattern mid-week.

Another shortwave through moving through the northwest upper flow
brings small precipitation chances to mainly northern and eastern
portions of the forecast area Sunday afternoon through Sunday
night and a brief cooldown for Monday. Highs Sunday will range
from the 20s east to 40s southwest, cooling down to the single
digits northeast and 30s southwest on Monday. 

After Monday, a stronger wave over the eastern Pacific will dig
into the Southwest U.S. developing a split flow pattern over the
region. At this time, this pattern looks to keep any significant
systems just to our north and well to our south.

As we get to the end of the forecast period, the split upper flow
pattern continues. but the northern stream jet sinks down closer 
to North Dakota bringing us a few more chances of light 
precipitation and strong winds, in other word, more of the same.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 114 AM CST Sat Feb 12 2022

Low VFR to MVFR ceilings are forecast at area terminals for a
period this morning along with scattered snow flurries. Chances
for light snow increase later this morning and through the
afternoon hours for KMOT, KJMS, and KBIS, with another round of
low VFR/MVFR ceilings and visibility likely. 

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Chill Advisory until 9 AM CST this morning for NDZ004-005-
012-013-022-023-025-036-037-047-048-050-051.

&&

$$

UPDATE...NH
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...NH