Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 080652
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1252 AM CST Thu Dec 8 2016

.UPDATE...
Issued at 1251 AM CST Thu Dec 8 2016

Main adjustment to the forecast was to blend current conditions
into the grids. The current headlines still look good with most
reduced visibilities in blowing snow in the current winter weather
advisory.

UPDATE Issued at 1045 PM CST Wed Dec 7 2016

Area of snow is quite persistent late this evening between
Aberdeen-Bismarck and Jamestown. This update for likely to
definite snow across the south central tonight. With very cold air
the precipitation amounts will be light but made the blowing snow
more widespread.

UPDATE Issued at 859 PM CST Wed Dec 7 2016

Will let the blizzard warning expire as winds have or will
diminish below 35 mph although 30 to 35 mph will be common
overnight with a few gusts to 40 mph early on. However as the
surface trough moves south through the region the band of snow
will move south as well and that will help improve the
visibilities which are now a half mile or better at many locations
in the blizzard area. The RAP model maintains its steady rise in
3hr pressures of 2 mb through the night and that should maintain
winds in the 30 to 35 mph range east central. So went with a
winter weather advisory through 15z. Also extended the wind chill
advisory another set of counties east tonight.

UPDATE Issued at 625 PM CST Wed Dec 7 2016

Canadian and NWS radars show the band of snow involved with the
blowing and drifting snow is moving south with the surface
pressure trough. The RAP model does project 2-3 MB pressure rises
every 3 hours across the east half of North Dakota at least
through most of the night. This will help to sustain the winds
but with the snow tapering off over time the blowing snow will be
reduced. So thinking about issuing winter weather advisory after
the blizzard warning expires at 9 pm. Will continue to evaluate.
Across the south central places like Bismarck will be on the edge
of wind chill advisory criteria and will continue to monitor for
eastward expansion of the wind chill advisory later this evening.

&&

.SHORT TERM...(This evening through Thursday)
Issued at 315 PM CST Wed Dec 7 2016

Blizzard conditions this evening highlight the short term
forecast.

Did upgrade the Winter Weather Advisory to a Blizzard Warning
across north central North Dakota through the James River Valley
through 03 UTC this evening. Surface and webcam observations
through 21 UTC are confirmed by multiple reports on social media
of the redevelopment of near zero visibility this afternoon
across the aforementioned areas in blowing snow and lightly
falling snow. The LAMP guidance is the preferred source for winds
as it is the highest and matches observations the best. This
suggests wind gusts in excess of 40kts may continue through 00
UTC, and only decreasing very slowly thereafter. The 12-18 UTC
global suites also support lightly falling snow to continue
through the evening as well. This all equates to a high likelihood
of blizzard conditions continuing into the evening.

No changes made to the remainder of the Winter Weather Advisory
or the Wind Chill Advisory at this time.

.LONG TERM...(Thursday night through Wednesday)
Issued at 315 PM CST Wed Dec 7 2016

Dangerous wind chills for much of the period and the potential
for accumulating snow on Saturday highlight the extended forecast.

The 12 UTC global suites are in good agreement on arctic high
pressure across the Northern Plains through Friday night.
Dependent on cloud cover, Thursday night into Friday morning may
be very cold with the arctic high centered over western and
central North Dakota with a large snowpack. Accumulating snow is
favored for Saturday across the area north of a surface low
forecast to propagate across the central plains. The arctic
airmass may rebuild across the area Sunday into next week.
Dangerous wind chills are possible at least during the overnight
and morning hours nearly each day across portions of western and
central North Dakota.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1251 AM CST Thu Dec 8 2016

VFR conditions are expected at KISN and KDIK today.
KBIS/KMOT/KJMS will transition from VFR/IFR conditions in blowing
snow early this morning to VFR conditions by the late morning hours.
Wind will diminish through the day today.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Chill Advisory until noon CST /11 AM MST/ today for
NDZ001>003-009>011-017>021-031>035-040>046.

Winter Weather Advisory until 9 AM CST this morning for NDZ004-
005-012-013-022-023-025-036-037-047-048-050-051.

&&

$$

UPDATE...CK
AVIATION...AJ



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