Area Forecast Discussion
Issued by NWS Bismarck, ND

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000
FXUS63 KBIS 131001
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
401 AM CST Wed Dec 13 2017

.SHORT TERM...(Today and tonight)
Issued at 400 AM CST Wed Dec 13 2017

Wind advisory and patchy light freezing drizzle and/or light snow
highlights the today period. Another clipper arrives tonight with
light snow and minor snowfall accumulations.

Per observations and BUFKIT soundings regarding the wind advisory,
it is marginal on the sustained winds and gusts, and we should be
able to chip away and remove counties from west to east through
the morning hours.

Latest water vapor imagery indicates an active northwest flow
continues into North Dakota, as successive clippers are passing
through just about every 24hours. This mornings clipper type cold
front is well south of the state, with its associated upper level
shortwave now pushing into northern South Dakota. Large chunk of
stratus is quickly shifting south from eastern Saskatchewan and
Manitoba, and into the Turtle Mountains as of this writing.
Followed the NBM sky grids which seemed to capture the clouds
well. Essentially once the stratus arrives, expecting it to linger
for the day along and east of a line from Williston to Bismarck,
which seems to line up along the low level baroclinic zone.
Farther to the west, low clouds will be in/out with breaks of
sunshine from time to time, especially in the southwest. Cooler
today with highs in the 30s.

The next mid/upper level shortwave supporting our next surface
clipper/cold front per water vapor imagery was located near
Yellowknife in the Northwest Territories of Canada. This will dive
southeast today, arriving into northwest ND by 06z Thursday.
Large scale ascent will increase and push from northwest to
southeast 06z-18z Thursday. GEFS Plumes across western/central ND
show decent clustering between 0.05 and 0.10 inch liquid amount
range. With average snow ratios around 13 to 1, forecast snowfall
totals between a half inch and one and one half inches from
tonight through Thursday morning can be expected. Despite this not
being a large amount of snow, it will occur during the Thursday
morning commute, so will message this mostly through social media
at this time.

One area will need re-evaluating is in southwest ND Thursday
morning, as strong winds, near or into advisory level per BUFKIT
soundings, may combine with snow for low visibilities and impact
to travel. Future shifts can re-evaluate the soundings with the
latest data to see if these trends continue. Elsewhere, winds will
range between 15 and 25 mph, with patchy blowing snow.

.LONG TERM...(Thursday through Tuesday)
Issued at 400 AM CST Wed Dec 13 2017

No shortage of additional clippers through the long term. As of
now, it appears Friday night, Saturday night, Monday, and late
Tuesday into Wednesday, are the favored time periods for each
passage through western/central ND.

A chance of snow can be expected with each clipper, along with brisk
winds/15mph to 25 mph. Strong winds are not expected at this time.
Trends continue for much colder air to pour into the northern high
plains late next week.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 400 AM CST Wed Dec 13 2017

Gusty winds to 35kt and stratus will be the aviation hazards this
Taf period. Currently, strong northwest winds are dominating the
terminals, and expect this to continue until mid/late afternoon
Wednesday. An area of stratus/mvfr cigs seen over south central
Saskatchewan will continue a southward push, reaching KMOT/KJMS
by 12z Wednesday, KISN/KDIK/BIS by around 15z. Mvfr cigs will
continue through the Taf period at KMOT/KJMS, but should improve
to low vfr at KISN/KDIK/KBIS during the afternoon. A brief period
of patchy light freezing drizzle is possible at KMOT/KJMS 12z-18z,
but with such a low probability and sparse coverage, will not
mention anything at these terminals.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 3 PM CST /2 PM MST/ this afternoon for
NDZ001>005-009>013-017>023-025-031>037-040>048-050-051.

&&

$$

SHORT TERM...KS
LONG TERM...KS
AVIATION...TWH



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