Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 201800

Area Forecast Discussion
National Weather Service Bismarck ND
1200 PM CST Tue Nov 20 2018

Issued at 1152 AM CST Tue Nov 20 2018

We bumped up temperatures for the west and south central. Also
lowered sky cover through mid to late afternoon. Otherwise no
significant changes to the going forecast.

UPDATE Issued at 950 AM CST Tue Nov 20 2018

Main issue for the morning update will be clouds and temperatures.
Currently, sunny areas are outperforming our hourly temperatures.
Utilized a blend of short term guidance for temperatures which
raised temperatures a little most areas. Also lowered clouds a
bit through early afternoon on the western fringe of the cloud
shield. Think this cloud shield will eventually make its way back
to the west, with low stratus/fog and maybe some freezing drizzle
tonight into Wednesday.


.SHORT TERM...(Today and tonight)
Issued at 321 AM CST Tue Nov 20 2018

Challenge through the short term period will be stratus/cloud
cover and associated temperatures, especially across central
North Dakota. Overall, a milder day compared to Monday`s highs.

For tonight, stratus returns to all of western/central North
Dakota with some prospects of patchy light freezing drizzle per
BUFKIT soundings.

Latest fog/stratus loop continues to show stratus streaming from
the southern Canadian Prairies into central North Dakota. At the
same time, the stratus is eroding from west to east, with sky
conditions trending clear in the west. This is in response to an
advancing warm front and associated low level warm air advection
and strong westerly winds just above the surface, aiding in
warming/drying aloft per BUFKIT soundings. Low pressure in
southwestern Manitoba is riding along the warm front and continues
to promote light snow across the Turtle Mountains. There could be
short period of light freezing drizzle, however the precipitation
looks to end by 12z/6AM CST Tuesday as the low shifts farther off
to the south and east. As the warm front propagate east today,
the back edge of this boundary will get hung up from north central
North Dakota into the James River Valley. In the vicinity of this
boundary will be a distinct cloud gradient of sunny conditions to
the west and south, and cloudy conditions north and east. With
that said, high temperatures today will reach the upper 40s
southwest, to the upper 20s and lower 30s east central.

Tonight, BUFKIT soundings as well as the NAM/GFS show the
baroclinic zone retrograding back into central North Dakota.
Sounding profiles across western and central ND indicate roughly a
2000ft-3000ft saturated layer, along with weak vertical motion.
Some hints even in the NAM that patchy light freezing drizzle will
occur along the boundary/central ND. Due to the transient nature
of this threat, nothing in the gridded data yet, but will pass
this along for the next shift to consider.

.LONG TERM...(Wednesday through Monday)
Issued at 321 AM CST Tue Nov 20 2018

The stratus deck and associated baroclinic zone from Tuesday night
will make little movement east during the daylight hours Wednesday.
Thus, a tight temperature gradient will be in place with highs in
the lower 50s far southwest, to upper teens around Rolla. In between
expect highs in the 20s to lower 30s for most areas. Soundings as
well as the operational NAM/GFS show the stratus holding steady
through the day along with patchy light freezing drizzle possible.
Plenty of sunshine will occur in the southwest.

A mid/upper level ridge will propagate from the northern Rockies
across North Dakota Wednesday night and Thursday. GFS soundings
show the low level moisture/stratus remaining trapped through
Thanksgiving Day across central North Dakota. If this trend
continues, then temperatures will not be as warm as the current
gridded forecasts have. Will continue to see how the stratus plays
and verifies with the model data through Wednesday before fully
going with this idea.

Two cold fronts will affect temperatures beyond Thanksgiving Day
and into the weekend. The initial cold front quietly pushes
through Friday, followed by a much stronger cold front Saturday.
The coldest air will arrive Sunday and Monday. At this time, there
will be some snow showers Saturday, but areal coverage remains
minimal. High temperatures Friday will be in the mid 30s to mid
40s, then teens and 20s for Sunday and Monday.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1152 AM CST Tue Nov 20 2018

VFR ceilings to begin the TAF period except for KJMS, which may
see a break in MVFR ceilings for a period this afternoon, but
predominantly MVFR expected. A frontal boundary will shift back
west late this afternoon and tonight bringing MVFR to IFR ceilings
and vsbys into KJMS and KBIS this evening. KISN and KDIK will see
possible MVFR to IFR ceilings late tonight into Wednesday morning.
Expect low ceilings, areas of fog and possible flurries and
freezing drizzle to linger through the morning hours once it
develops as each TAF site.




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