Small Craft Advisory 173, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
340 PM AKDT MON SEP 26 2016

.DISCUSSION...The models are in good agreement in the short term
with decent run to run consistency. the biggest forecast challenge
in the short term will be along the west coast where the latest storm
surge guidance continues to show the potential for elevated water
tomorrow night into wednesday (more on this below).

Aloft...At 500 hpa a 516 dam low sits just north of Barrow while
543 dam low currently sits over the Alaska Peninsula. Both of
these features will be pushed off to the east by a quickly moving
upper level ridge. The ridge axis will be along a line from Barrow
to Bristol Bay by late Tuesday afternoon and will be along a line
from Barter island to Anchorage by Wednesday morning. The ridge
will be pushed eastward by a trough associated with a 509 dam low
over the Chukotsk Peninsula.

Surface...A 1005 mb low north of Deadhorse will continue to push
to the east. a weak cold front stretches southwest from the low
and currently lies along a line from Deadhorse to Unalakleet. This
front will push eastward tonight. High pressure will build over
the north slope and west coast on Tuesday.  A strong weather
system will move into the central Bering Sea by Tuesday evening
and the warm front will surge up the west coast early very
Wednesday morning. By noon on Wednesday a rapidly moving cold
front will be over the Bering Strait and pushing east into the
west coast and riding north over the ridging that will persist
over the southern third of the state.

West coast and Western Interior...Areas from Galena east will
seen some rain showers and patchy fog this evening as the
aforementioned cold front moves off to the west. Tuesday will be
relatively quiet across the west coast before the next big storm
system begins to move in Tuesday night. Model runs over the past
few days have been fairly consistent in brining in a decent storm
into the west coast Tuesday night into Wednesday. This system will
bring about a 12 hour period of strong westerly winds into Norton
Sound beginning early Wednesday. This will result in increased
water levels in Norton Sound on Wednesday. With this package I
have issued a Coastal Flood Warning for Zone 212 due to the
potential for minor coastal flooding. The GFS based storm surge
guidance is showing the highest storm surge values in Norton Bay
on Wednesday, while storm surge values in excess of 4 feet are
expected in Unalakleet. Elsewhere along the west coast there is
the potential for some elevated surf and minor coastal erosion with
this system, thus I have issued high surf advisories for zones
207, 209, 211 and 214. The high surf conditions will develop from
north to south beginning Tuesday evening. This system will also
bring winds in excess of 40 mph to the coastal areas as well as
widespread rainfall on Wednesday.

Arctic Coast and Brooks Range...Some snow is expected along the
cold front as it moves eastward. The font is relatively fast
moving, so I don't expect a lot of snow accumulation. At most two
inches is possible in the Brooks Range. Cloudy conditions are
expected behind the front overnight with stratus moving in.
Relatively quiet conditions are expected on Tuesday. A weather
system will move from west to east across the north slope on
Wednesday bringing another round of snowfall. Models are in
relatively good agreement that a high amplitude upper level ridge
will build over the north slope over the weekend resulting in
above normal temperatures.

Central and Eastern Interior...The patchy dense fog that was over
a large portion of the central Interior this morning finally
lifted early this afternoon. Fog may redevelop this evening after
sunset in some areas; however, this will be kept somewhat at bay
by the increased cloud cover associated with the eastward moving
cold front. Showers are expected along the front as it moves
east. The precipitation type will be rain this evening. The
precipitation type will transition to or mix with snow later on
tonight. As the front moves eastward tonight models suggest that
it fizzles out a bit, thus pops along the front gradually decrease
overnight. We are not expecting any significant snow accumulation
along the front. Tuesday through Wednesday morning look to be
relatively quiet across the interior. The next round of
preciptiation will be Wednesday evening into Thursday as a short
wave moves across the area.

Coastal Hazard Potential Days 3 and 4...see west coast section
above, in addition to the further in the extended the GFS is
showing the potential for southeasterly winds in excess of 40 kts
across norton sound for a 12 to 18 hour period on Saturday.

&&

.HYDROLOGY...no concerns at this time.

Marine...Winds coming up in advance of the weather system
will bring small craft conditions to some western areas tomorrow
increasing to Gales tomorrow night.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Coastal Flood Warning for AKZ212.

High Surf Advisory for AKZ207-AKZ209-AKZ211-AKZ214.

Dense Fog Advisory for AKZ221.

Winter Weather Advisory for AKZ217.

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

SEP 16