Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 130528
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1128 PM CST Tue Dec 12 2017

.UPDATE...
Issued at 1128 PM CST Tue Dec 12 2017

Latest water vapor shows the mid/upper level shortwave trough now
aligned from north central into western ND. Regional radar has an
area of rainshowers across the Turtle Mountains, with Rolla now
reporting rain with a temperature of 36F, and nearby RWIS/road
temperatures at Dunseith of 34F. Thus, no worries for freezing
precipitation at the moment. Latest RAP BUFKIT soundings indicate
a possible period of light/spotty light freezing rain/snow 12z-
18z Wednesday for north central ND and into the northern James
River Valley, but omega/vertical motion is either weak, or even
downward (sinking motion) during the time period that light
freezing rain would develop. Mixing heights increase and rise into
the ice crystal production temperature (-10C to -12C) between 15z
and 18z, thus should see more in the way of light snow if any
precipitation does develop. Gusty winds will continue overnight
into mid afternoon as previously forecast, so the wind advisory
remains in good standing.

UPDATE Issued at 925 PM CST Tue Dec 12 2017

Clipper has pushed well into the area, with very gusty winds being
reported in far northwest North Dakota both by observations and by
spotter reports. Have gone ahead and extended the wind advisory
into that area and pushed it into effect earlier. Gusty winds will
continue to spread across the area. As for precipitation, spotters
have reported no precipitation so far over the west with cloud
bases remaining quite high. Therefore, will keep precipitation
chances on the low side.

UPDATE Issued at 633 PM CST Tue Dec 12 2017

Clipper is about to move into the area, with increasing westerly
to southwesterly winds ahead of the system. High clouds continue
to stream in ahead of the system, so have increased cloud cover
through the evening. Otherwise, previous forecast looks on track.

&&

.SHORT TERM...(This evening through Wednesday)
Issued at 255 PM CST Tue Dec 12 2017

A clipper will move through North Dakota tonight. It will arrive
in northwest North Dakota late this evening, and exit south
central North Dakota by early Wednesday morning. Strong pressure
rises, cold air advection and and a well mixed layer will result
in windy conditions late tonight and tomorrow. West to northwest
winds will increase to around 30 mph with gusts to 45 mph
overnight and remain strong through the early afternoon hours
Wednesday.

In terms of precipitation, the latest 12z global model runs and
short term high-res models depict less moisture than earlier
runs. Soundings show a wintry mix possible from the Turtle
Mountains south into the James River Valley tonight. However, with
only very light amounts possible, impacts should be minimal.
Further west, temperatures should be warm enough through most of
the night to keep any precipitation that does develop in the form
of rain. Light freezing rain and/or snow are possible across
portions of northern and central North Dakota Wednesday morning as
dry air aloft moves in and limits ice production. However, with
very little lift within the low level saturated layer generally
only a shallow stratus layer is expected with perhaps patchy light
precipitation at times.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 255 PM CST Tue Dec 12 2017

The long term remains active with successive clippers resulting in
periods of gusty winds and continued chances for precipitation.

Another clipper in the northwest flow aloft will sweep through
Wednesday night/Thursday. Winds will not be as strong, and
precipitation looks to be mainly in the form of light snow.
Central ND could see less than inch through Thursday morning.
Another break in the weather Thursday night into Friday morning,
followed by the next clipper Friday afternoon into Saturday
morning, and another late Sunday into Monday.

Beyond this long term period, the weather pattern is still trending
much colder towards the end of next week. More on this in future
discussions.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1128 PM CST Tue Dec 12 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/ Wednesday for NDZ001>005-
009>013-017>023-025-031>037-040>048-050-051.

&&

$$

UPDATE...KS
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...KS


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