Small Craft Advisory 45, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
531 AM AKDT Thu Jul 6 2017

.DISCUSSION...
Overall, the models are in good agreement out through the weekend.
The main forecast challenges for today will be rain and gusty
winds along the West Coast as well as Red Flag conditions in the
Southeastern Brooks Range and the Yukon Flats.

Aloft, at 500 mb, a ridge currently along a McGrath to Eagle axis
currently dominates the weather pattern over much of northern
Alaska. This ridge will persist through the weekend gradually
moving northward. A 544 dam low currently over the Chukotsk
Peninsula will move to the north today into early Friday around
the northwest side of the ridge. After this low passes by it will
allow the upper ridge to build westward across the Bering Strait.
A 553 dam low will move into the northern Gulf of Alaska on Friday
where it will more of less stay through the weekend.

At the surface, a 996 mb low near Banks Island will move north and
east today. A weather front associated with this low will drag
over the northwest Arctic Coast through Friday before being
pushed offshore by building high pressure. A 1022 mb high sits in
the northern Gulf of Alaska with a ridge extending into the
western Interior. The surface ridge will build west and strengthen
over the next few days. A 1019 mb high near Mackenzie Bay will
slowly move to the east today. A thermal trough stretching from
Arctic Village to Old Crow, YT will persist today. A thermal
trough will develop in the southeast Interior this afternoon
stretching from Beaver to Northway. On Friday and Saturday the
thermal trough will stretch from Chalkyitsik to Northway.

West Coast and Western Interior: As the upper level low move up
and over the ridge today a front will bring rain to much of the
west coast north of Norton Sound. Rain will begin this morning and
will continue into Friday afternoon with the heaviest rainfall
expected in today in the afternoon and evening. 0.5 to 0.75 inches
of rain is possible through Friday afternoon on St. Lawrence
Island, along the Bering Strait Coast, the Chukchi Sea Coast and
in the lower Kobuk and Noatak Valleys. A tight pressure gradient
will result in strong winds along the coast through early Friday.
The ridge will build into the coastal areas for the weekend
resulting in improved conditons. The ridge will keep things
tranquil in in the Western Interior for the next few days with
temperatures in the 70s.

Arctic Coast and Brooks Range...Periods of rain are expected for
areas from Barrow west through Friday afternoon. East of Barrow,
expect some clearing today with clouds increasing again tomorrow.
Strong winds will persist today near Cape Lisburne. Very warm
temperatures are expected today along the Arctic Coast east of
Barrow with temperatures in excess of 70 degrees for some
locations.

Central and Eastern Interior: Warm conditions will persist for
the next few days with high temperatures in the upper 70s and 80s
for many locations. Some isolated thunderstorms possible this
afternoon and evening southeast of a line from Eagle to Healy.
There will be increased chances for some showers on Friday south
of Livengood due to an easterly wave moving around along the south
side of the ridge. Isolated afternoon and evening thunderstorms
along the thermal trough again on Friday (mainly along a line from
Chalkyitsik to Healy).

Coastal Hazard Potential Days 3 and 4...
Persistent southeast flow will bring increased wave action to
some of the outer coastal areas and St Lawrence Island with
nearshore wave heights to 4 to 7 feet, but no significant erosion
is expected.

&&

.FIRE WEATHER...
Red Flag Warnings have been issued for this afternoon and evening
for the Yukon Flats and the Southeastern Brooks Range. These
areas will see high temperatures in the upper 70s to lower 80s
combined with winds around 15 mph and minimum relative humidity
values in the low 20s (particularly east of a line from
Chalkyitsik to Arctic Village where the driest air is expected.
Near Red Flag conditions are possible along the Alaska Highway
from Delta to Northway where conditions will be warm enough and
dry enough; however, the winds will be the limiting factor.

Elsewhere across the Interior minimum relative humidity values
will be above 25 percent. There will be some increase in minimum
RH values in the extreme southern Interior on Friday as an
easterly wave moving around the south side of an upper ridge will
bring some moisture. On Friday and Saturday the driest areas will
be located close to the Canadian Border from Eagle north to the
Brook Range with some areas approaching Red Flag Conditons.

Some isolated thunderstorms possible this afternoon southeast of
a line from Eagle to Healy. There will be increased chances for
some showers on Friday south of Livengood due to an easterly wave
moving around along the south side of the ridge. Isolated
afternoon and evening thunderstorms along the thermal trough again
on Friday (mainly along a line from Chalkyitsik to Healy).

&&

.HYDROLOGY...
Rivers in the Fortymile Basin will continue to run high. Expect
them to fall over the next couple of days.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning for AKZ218-AKZ220.

Small Craft Advisory for PKZ200-PKZ210-PKZ215-PKZ220-PKZ230.

Gale Warning for PKZ225.

Brisk Wind Advisory for PKZ235-PKZ240-PKZ245.
&&

JUL 17