Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 161753
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1153 AM CST Thu Nov 16 2017

.UPDATE...
Issued at 1145 AM CST Thu Nov 16 2017

Warm front across far southwest North Dakota will move northeast
this afternoon. While temperatures southwest have lagged the
hourly trends, when the front passes temperatures should rise
rapidly there. Otherwise current forecast trending ok.

UPDATE Issued at 846 AM CST Thu Nov 16 2017

The stratus area is expanding into Dickinson and Hettinger which
may create an issue with temperatures today. However the short
range models do move the stratus west and north by afternoon
which may allow temperatures to warm to the forecast highs. Too
much uncertainty to change temperatures much today, and they dont
look unreasonable. Otherwise current forecast looks ok.

UPDATE Issued at 637 AM CST Thu Nov 16 2017

Going forecast remains in good shape with some flurries passing
through northern portions of the area.

UPDATE Issued at 432 AM CST Thu Nov 16 2017

Quick update to add isolated flurries and patchy fog north through
mid morning. Surface observations along with webcams from Tioga
to Stanley, east to Rugby and Rolla indicate patchy fog and isolated
flurries. Updates to zones and state forecast have been sent.

&&

.SHORT TERM...(Today and tonight)
Issued at 303 AM CST Thu Nov 16 2017

Stratus during the morning over a large portion of central ND is
the highlight in the near term. A warm frontal passage today,
followed by a cold frontal passage tonight with a slight chance of
a wintry mix are the other highlights in the short term period.

Per satellite, surface observations, and webcams, an area of
stratus continues along and east of a line from Crosby to Tioga,
to Glen Ullin, Bismarck and into Wishek. This is initialized well
by the HRRR/GFSLamp/and RAP13 Ceiling Forecast, which begins to
erode and retreat the stratus from southwest to northeast between
13z-15z, completing the journey in the Turtle Mountains by late
afternoon. Concur with this idea as this follows the location and
passage of the sfc-850mb baroclinic zone/warm front, with low
level winds veering from southeast to southerly and advecting in
drier air. Although there will be a depletion of low level clouds,
warm air advection/rising air will continue to favor a mostly
cloudy day as mid/upper level clouds stream from west to east.

The latest water vapor imagery shows an upper low/longwave trough
located over western British Columbia. A lead shortwave trough
was seen over west central ALberta. Forecast models initialize
this shortwave well, and forecast to move it into eastern Ontario
by 12z Friday. Surface low pressure associated with the mid level
shortwave was located in far southeastern British Columbia, and
will deepen as it moves east to northeast today through tonight.
In doing so, and as mentioned above, strong warm air advection
continues ahead of this system through the daylight hours, with
the aforementioned warm front moving from west to east and into
the Turtle Mountains and James River Valley by 00z Friday. A cold
front emanating from the surface low as it moves into Saskatchewan
and Manitoba tonight, will push across wester and central ND.
Enough large scale ascent per NAM/GFS for a slight chance of a
wintry mix along and behind the front. The high resolution models
are pretty much void of any precipitation, with the
GFS/ECMWF/Canadian producing a narrow line of light precipitation.
The cold front overall is weak, so the above/slight chance seems
reasonable and will follow.Highs today will range from the mid 20s
in the Turtle Mountains to the upper 40s to lower 50s in the
southwest.

.LONG TERM...(Friday through Wednesday)
Issued at 303 AM CST Thu Nov 16 2017

Friday will see an Alberta clipper slide int eastern Montana
during the afternoon. A mid/upper level shortwave will also shift
east from southern Montana into western/central South Dakota.
Synoptic scale ascent atop of low level frontogenesis across and
sufficient mid level lapse rates/around 7C/km will result in a
chance for rain/snow south of Interstate 94 Friday. Much colder
again behind the clipper Saturday with highs in the 20s, to upper
30s southwest. Northwest flow aloft continues Sunday with a dry
day and highs rebounding back into the 30s and 40s.

Beyond Sunday, timing differences between the GFS/ECMWF becomes
readily apparent. Both agree that another clipper type cold front
will sweep through, with the GFS signaling it during the day
Monday, while the ECMWF does so Monday night. Either way, limited
precipitation, but strong winds advertised by both models could
result in a solid wind advisory and/or high wind warning for
western/central ND. The pattern remains progressive, with a
break/dry day Tuesday behind the clipper, followed by a couple of
warm air advection events. Light precipitation associated with the
warm air advection per GFS, but mostly dry on the ECMWF. With the
fast nature/progressive flow at this time through the long term
period, not expecting any widespread long duration precipitation
events. High temperatures will fluctuate quite a bit, with the
coldest air Tuesday behind the clipper - highs in the 20s for most
locations. Sunday/Monday/Wednesday/Thursday, highs will be in the
30s and 40s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1145 AM CST Thu Nov 16 2017

Hazards to aviation include IFR conditions to the north of a warm
front across far southwest North Dakota and gusty Southeast winds
across the James River Valley. As the front lifts north this
afternoon conditions will become VFR at all TAF sites. Winds will
diminish by 04Z KJMS.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...WAA
SHORT TERM...KS
LONG TERM...KS
AVIATION...WAA


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