Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 031744

Area Forecast Discussion
National Weather Service Bismarck ND
1144 AM CST Sat Dec 3 2016

Issued at 1143 AM CST Sat Dec 3 2016

Surface observations and regional radar show the leading edge of
light snow now into northeast MT and impinging into far northwest
ND at this time. Weak 3hr pressure falls were focused across
western ND with Isentropic upglide evident per GFS 290K pressure
surface. Sidney MT reported 4sm -sn last hour and expect this
area of light snow to propagate east as surface pressure falls and
isentropic lift shift east through tonight. Visible imagery was
showing pockets of clearing ahead of this vertical motion field
but clouds will fill back in later this afternoon. Minor updates
to sky grids with the overall forecast on track.

UPDATE Issued at 856 AM CST Sat Dec 3 2016

Given little mixing, extended the mention of fog across central
North Dakota through at least midday today. This is supported by
the 12-13 UTC HRRR/RAP visibility forecasts.

UPDATE Issued at 634 AM CST Sat Dec 3 2016

Areas of fog have developed mainly over south central North
Dakota, but will leave the mention also in the west as a few obs
having gone up and down over the past few hours. Have also
advanced timing a bit of the snow coming in from eastern Montana,
as it is moving a bit faster than previously thought.


.SHORT TERM...(Today and tonight)
Issued at 314 AM CST Sat Dec 3 2016

Current surface analysis places low over southern Alberta with
trough dropping through eastern Montana towards the Black Hills.
High remains over the central plains into the midwest. Upper level
analysis places short wave sliding through central into eastern
Montana producing some light snow. Over our area, skies have
gradually been clearing over western locations with some fog
developing, while cloud cover lingers over the east.

For today...areas of fog will dissipated by mid-morning as
aforementioned short wave continues its approach. Areas of snow
will develop and push over the area today into this evening,
although accumulations should remain on the light side.

.LONG TERM...(Sunday through Friday)
Issued at 314 AM CST Sat Dec 3 2016

Weak ridging between systems will bring dry conditions during the
day on Sunday. Our first real shot of cold air for the season
will start to push into the area on Monday as a surface low
deepens over the plains and lifts over Manitoba/Ontario allowing
an arctic airmass to pour into the region. This will also bring a
good chance for snow through the area with modest isentropic lift
to start followed by enhanced broad scale lift from trough
swinging around upper low to the north. Temperatures will fall
through the day on Tuesday as cold air continues to pour in, while
breezy conditions will contribute to bringing frigid wind chill
values, particularly Tuesday night/early Wednesday where readings
as low as 30 below are expected. Frigid airmass remains over the
area through remainder of the work week.


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1143 AM CST Sat Dec 3 2016

Pockets of sct/bkn ifr cigs at KBIS will temporarily improve to
vfr this afternoon before falling back to mvfr/ifr by 03z Sunday.
KJMS will continue in mvfr status until 09z Sunday when cigs are
expected to deteriorate to ifr. Elsewhere, vfr at the remaining
terminals begin the TAF period, but will also trend to mvfr Saturday
afternoon through Saturday night. A vcsh was mentioned at all terminals
except KDIK. Expect a possible light period of snow during this TAF
period with a dusting of snow accumulation.




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