Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 252046
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
246 PM CST Sat Feb 25 2017

.SHORT TERM...(This evening through Sunday)
Issued at 246 PM CST Sat Feb 25 2017

Highlights in the short term period are: first, a period of
moderate to heavy snowfall northwest, north central, and into the
northern James River Valley this afternoon into tonight. A Special
Weather Statement has been issued informing the public of between
2 and 4 inches of snowfall expected. Secondly, ice jam impacts
remain possible along the Yellowstone River and the Missouri River
upstream of Williston. Continued to advertise this in a Hydrologic
outlook. Please see the Hydro discussion below for further details.

High resolution models as well as the NAM/GFS/ECMWF indicative in
a period of moderate to heavy band of snow developing northwest
this afternoon, then progressing southeast into the northern James
River Valley tonight. Latest water vapor imagery shows a shortwave
trough into southeast Saskatchewan and northwest North Dakota.
Radar and surface observations show light snow northwest into portions
of north central, with 3hr pressure falls maximized in northeastern
Montana. Baroclinic zone/frontal boundary extends from northeast
Montana into southern North Dakota. Expect snowfall to increase in
intensity as a surface low pressure develops and deepens in response
to increased frontogenetical forcing aligning with synoptic scale
ascent across northwest into north central. With mid level lapse
rates around 6.5C/Km and the approach of a 70kt jet streak/left
exit region riding atop, expect a deeper/stronger circulation to
evolve, leading to period of moderate to heavy banded snow. Thus,
have strongly followed the higher resolution models on POPS and
QPF this afternoon into tonight resulting in a snowfall swath of
between 2 and 4 inches from northwest, north central, and into the
northern James River Valley. In addition, followed the previous
shifts idea of increased winds resulting in patchy blowing snow. A
3hr pressure bubble rise continues per GFS which comes in behind
the surface low this evening and overnight. Expect the snow/wind
to taper off tonight from northwest to southeast.

Another shortwave/weak clipper system swings through Sunday afternoon
and evening with a chance of snow northwest and north central. Snowfall
accumulations are light, a couple tenths of an inch.

.LONG TERM...(Sunday night through Saturday)
Issued at 246 PM CST Sat Feb 25 2017

Northwest flow aloft dominates through Thursday resulting in below
normal high temperatures and near daily chances for light snow as
several weak clipper systems slide through. At this time, nothing
significant in terms of precipitation is expected. The upper flow
becomes zonal but remains progressive Friday into next weekend.
This results in moderating temperatures with normal to above
normal highs Friday and Saturday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 246 PM CST Sat Feb 25 2017

Widespread MVFR cigs will continue over much of the area today
into tonight, with areas of IFR visibility developing,
particularly north, as the next round of snow pushes in later
today into this evening. Conditions will gradually imrove Sunday
morning, with most locations returning to VFR.

&&

.HYDROLOGY...
Issued at 246 PM CST Sat Feb 25 2017

Occasional ice jams due to ice breaking up continue along the
Yellowstone River in eastern Montana. River rises will be
possible on the Yellowstone in North Dakota from Fairview,
downstream to the Missouri River near Buford when ice jams
release. Ice affected rises may also be possible along the
Missouri River from the Yellowstone downstream to Trenton and
Williston. Those with interests along the Yellowstone and Missouri
Rivers near the Montana border should be prepared for the
possibility of rising river levels.

&&

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

$$

SHORT TERM...KS
LONG TERM...KS
AVIATION...JJS
HYDROLOGY...JJS



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