Winter Storm Warning 17, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
346 PM AKDT Sun Oct 14 2018

.DISCUSSION...
Overall the models are in good agreement in the short term with
the main synoptic scale features and paint an active picture for
much of the Interior over the next few days.

Aloft, at 500 mb, a 516 dam low south of Adak will move to the
east tonight before turning to the north on Monday reaching
Bristol Bay Monday afternoon. As the low moves to the east it will
help to pump up a ridge along the Canadian Border that will bring
southerly flow across much of the forecast area. The low over
Bristol Bay will persist for much of the upcoming week, although
it will weaken after Tuesday night. The ridge over the Canadian
Border will push to the east Tuesday night turning the flow aloft
more southwesterly.

At the surface, a 970 mb low south of Unalaska will push east
tonight before turning to the north on Monday. The low will reach
Bristol Bay by Monday afternoon where it will persist through
Wednesday night, gradually weakening in place. A ridge of high
pressure will build east over eastern Russia Monday. High
pressure will persist over the Arctic for much of the week.

Central and Eastern Interior: Relatively quiet for most areas
tonight, although fog is expected in many valley locations around
the Interior. The next system will begin to approach from the
south on Monday. During the day a trough will strengthen just
north of the Alaska Range. This will cause winds to increase
across the Interior. Southerly gap winds will reach advisory
criteria in the eastern Alaska Range Monday night with advisory
level winds persisting into Tuesday. I opted to go ahead and issue
Wind Advisories for zones 223 and 226 for the expected winds.
Precipitation associated with this system will spread north Monday
evening. Strong southerly flow over the Alaska Range will keep
the snow level above 6000 feet south of the Yukon River early
Tuesday before decreasing to around 4000 feet late Tuesday.
Because of this, precipitation associated with this system is
expected to be rather messy, with a mixed bag of rain, freezing
rain and snow. Initially, on Monday night, the southerly winds
will help to limit the potential for precipitation from just north
of the Alaska Range to just north of Fairbanks. From Livengood
north to the Yukon River freezing rain is expected at times Monday
night and Tuesday. Because of the potential for freezing rain I
am issuing a Winter Storm Watch for zone 220 for Monday night into
Tuesday. North of the Yukon river, we expect to 2 to 7 inches of
snow Tuesday into Wednesday with high accumulations the closer you
get to the Brooks Range. Zones 218 and 219 will likely need a
winter weather product with this system; however, we will hold off
at this point with putting any out. On Tuesday, the flow aloft
turns a little bit more southwesterly allowing for higher PoPs in
the Fairbanks area. For Fairbanks we are expecting rain as the
precipitation type with this system. West of Fairbanks, there is
some potential for some light freezing rain early in the day on
Tuesday from Tanana south to Minchumina; however the precipitation
will change over to rain later in the day. Precipitation with
this system is expected to taper off south of the Yukon River
Tuesday evening and will taper off north of the Yukon River early
Wednesday morning. We liked the NAM solution as far as timing
goes. The GFS wants to hold onto the precip over the Fairbanks
area well into Wednesday. We did hint at this, keeping a slight
chance of PoPs for Fairbanks for Wednesday morning. If the GFS
solution does pan out, light freezing rain is possible for
Fairbanks early Wednesday; however, right now our current thinking
is that the chances of this happening is quite low. The GFS is
currently hinting at another system moving to the north Thursday
night into Friday thanks to a strong low in the Gulf of Alaska.

North Slope and Brooks Range: Some light snowfall is expected in
the eastern Brooks Range and along the eastern Arctic Coast this
evening. Any snowfall will taper off by early Monday morning.
Snowfall associated with the next system will begin in the Brooks
Range on Tuesday. 4 to 7 inches of snow is expected on the south
side of the Brooks Range before snow tapers off on Wednesday. The
north slopes of the Brooks Range will see lesser amounts due of
downsloping. Snowfall with this system will begin late Tuesday
along the Arctic Coast with the precipitation lasting into
Wednesday evening. Snow amounts along the coast with this system
look to be around 2 to 5 inches. Easterly winds along the coast
will pick up Tuesday with gusts up to 40 mph possible east of
Deadhorse (although the strongest winds look to remain offshore).

West Coast and Western Interior: The next front looks to bring
spread rainfall north along the coast late Monday into Tuesday.
With the low persisting in the Bristol Bay we expect that
conditions will remain unsettled through the middle of the week.
The combination the low moving into Bristol Bay combined with
high pressure building over eastern Russia will cause will cause
strong northeasterly winds to develop over the Bering Sea and
along the west coast. The strongest winds over a land area will be
over St. Lawerence Island where gusts around 50 mph are possible
early Tuesday. Right now, the wind direction doesn't look
favorable for coastal flooding issues on St. Lawrence Island for
Tuesday (the surge guidance is actually showing negative values).
The winds become more northwesterly for St. Lawrence Island on
Wednesday; however, at that point they are also starting to die
down. We will have to watch this area closely. At any rate, the
waters just offshore from St. Lawrence Island look to be quite
rough early this week. Elsewhere, we expect a lot of patchy fog
over the western Interior tonight into early Monday.

Coastal Hazard Potential Days 3 and 4...None; however, see West
Coast section above for issues in the shorter term.

Coastal Hazard Potential Days 3 and 4...None.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Wind Advisory for AKZ223-AKZ226.

Winter Storm Watch for AKZ220.

Winter Weather Advisory for AKZ218.

Small Craft Advisory for PKZ200-PKZ210-PKZ220-PKZ225-PKZ230.
&&

OCT 18