Area Forecast Discussion
Issued by NWS Bismarck, ND

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000
FXUS63 KBIS 291823
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1223 PM CST Tue Nov 29 2016

.UPDATE...
Issued at 1210 PM CST Tue Nov 29 2016

Latest trends using the Canadian and US radar data give support to
the short range meso and NAM/GFS solutions for this afternoon. A
band of moderate to heavy snow will move through central North
Dakota this afternoon and based on the NAM forecast soundings
which show the dendritic growth zone deepening a bit in the
sounding profile the moderate snow will potentially will extend
into the evening hours and even after midnight as several other
higher intensity snow periods will follow.

We expect another 4 to 6 inches of snow from Stanley to Minot to
Rugby south to Dickinson to Bismarck and Steele south to the South
Dakota border by Wednesday early afternoon. Snowfall totals of 18
to 24 inches now seem likely across central North Dakota,
particularly from Minot to Stanley to Beulah and Hazen with 12 to
18 inches across a broad area of central North Dakota.

Across the James river valley the rain will change to snow
tonight then accumulate 3 to 5 inches.

UPDATE Issued at 840 AM CST Tue Nov 29 2016

Band of light to moderate snow continues across central North
Dakota with light snow west. Winds gusting to 40 mph west. Current
forecast trending well.

UPDATE Issued at 618 AM CST Tue Nov 29 2016

Current forecast remains on track with only changes needed were to
match current conditions. Snow amount reports continue to trickle
in early this morning. Please see the latest Local Storm Report
(LSR) for current updates.

&&

.SHORT TERM...(Today through Wednesday night)

Issued at 421 AM CST Tue Nov 29 2016

Forecast highlights in the short term period will continue to
focus on the ongoing winter storm.

Currently, stacked low pressure remains centered over far
southeastern ND early this morning, with precipitation bands
continuing to rotate around the storm across the Dakotas
underneath a waning TROWAL. All snow across western and central
ND. Embedded energy rotating around the low producing enhanced
areas of snowfall at times, but not as widespread as Sunday night
and Monday. In addition to the snow, gusty northwest winds
persist thanks to strong gradient forcing and pressure rises.

Regarding winds: 1000-900MB geostrophic winds remain robust at
45-55KTs through this afternoon, then begin to decrease this
evening. BUFKIT analysis shows 35KTs of wind available within the
mixed layer with a layer of 40-45KTs just above the top of the
mixed layer today. Thus winds will remain gusty for a good part of
the day before slowly winding down tonight.

Regarding snow: we are seeing this morning more light snow versus
heavy snow, with only pockets of moderate. For the most part this
is due to the original TROWAL of this storm washing out as it
wraps back eastward around the low weakening thermal lift and
widespread strong forcing. This looks to continue through the
morning with only an inch or two of new snow on average through
18Z. However, a secondary TROWAL is already underway wrapping
westward into southeastern Manitoba. This feature will then rotate
southwest into central ND this afternoon and evening when I expect
our snowfall to ramp back up first over central ND then slowly
moving west after 00Z into portions of western ND. Latest
ECMWF/GFS/NAM all depict this rather well with their QPF output,
and with blended snow ratios yields another 4-7 inches of new snow
mainly over central areas of the state centered along the 83
corridor, then south & west of the Missouri River to about Highway
22 tonight.

The addition of this new snow forecast combined with what already
fell produces a new storm total snowfall map with a large area
over central ND at 14-18 inches, and now with pockets of nearly
two feet! This is truly a significant storm and will be one to
remember for a long time.

Stacked low pressure begins to finally move east tonight towards
Wednesday morning along with the secondary TROWAL wrapping back
southeast into the low. This decrease in forcing will see the
areal coverage and intensity of snow greatly diminishing with
time overnight tonight into Wednesday morning, with only scattered
light snow by Wed afternoon.

Winter weather headlines will continue as is.

.LONG TERM...(Thursday through Monday)

Issued at 421 AM CST Tue Nov 29 2016

For the most part the long term period will remain quiet with
near seasonal temperatures.

Later in the period Monday - Tuesday, both the ECMWF and GFS
develop a long wave trough over the western CONUS and bring a
strong embedded S/WV through the Northern Plains. This smaller
scale feature looks to be fairly progressive as it swings through
so any precipitation should be limited. The main highlight with
this system will be the much colder air surging south-southeast
into the region after Monday, possibly our first Arctic plunge of
this winter, with -20F 850mb temps advertised. Forecast blender
gives us highs in the teens for next Tuesday. Will continue to
monitor and message accordingly in our products.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1210 PM CST Tue Nov 29 2016

A winter storm system will impact all of western and central ND
through Wednesday. Snow with areas of blowing snow for the west half
of the state, including KISN, KMOT, KDIK, and KBIS. A rain/snow mix
is in store for KJMS. IFR/MVFR visibilities and ceilings expected
through the forecast period. An enhanced area of snowfall is
expected from 18z through 06z tonight, where moderate to heavy
snowfall is expected. Northwest winds of 20 to 30 mph with higher
gusts will create areas of blowing and drifting snow for the west
half of the state.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 6 PM CST /5 PM MST/ Wednesday for
NDZ001>005-009>013-017>023-031>036-040>047-050.

Winter Weather Advisory until 6 PM CST Wednesday for NDZ025-037-
048-051.

&&

$$

UPDATE...WAA
SHORT TERM...NH
LONG TERM...NH
AVIATION...JV



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