Area Forecast Discussion
Issued by NWS Fairbanks, AK

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FXAK69 PAFG 211146
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
346 AM AKDT Mon Aug 21 2017

.DISCUSSION...

Models...Good agreement continues from run to run in the short
term solutions. From Wednesday on there are significant
differences in the guidance that will need to be sorted out.
Initialization was good when compared against the 21/06Z local
surface analysis. Precipitation being reported on the West Coast
Outer Capes matching up well with guidance timing as well. Still
going to have some problems timing the shortwaves as they spin
across the forecast area through the week.

Aloft...At 500 hpa...Long wave trough persists over the state
extending from high in the Arctic to the north Pacific roughly
over 155W this morning sliding east over 145W by Tuesday morning.
A 536 dam low 400 nm northwest of Point Barrow will move northeast
to 600 nm northeast of Point Barrow by Tuesday morning and 800 nm
northeast of Point Barrow by Tuesday morning. Continuing
northeast into the high Canadian Arctic Wednesday. A 541 dam low
that was over Anvik yesterday is 400 nm south of Kodiak City this
morning and will move to 300 nm southwest of Yakutat by Tuesday
morning, then south of Ketchikan by Wednesday evening. A 543 dam
low develops this morning near Wrangel island and will dig
southeast into the trough as heights fall. The low will move over
the Upper Noatak by Tuesday morning, and the Upper Kobuk Basin by
Wednesday morning at 539 dam. The low will stall over the Central
Brooks range Wednesday night while several shortwaves rotate
around it. Ridging has rotated over the central Bering Sea this
morning with 560 dam heights pushing north over the Gulf of
Anadyr. As the ridge rotates to the east, a shortwave associated
with the low over the Chukchi Sea will squash it keeping the ridge
south of St Matthew Island, Nunivak Island, and the Alaska Range.
At 850 hpa...Temperatures slightly warmer today across the area,
then slowly cooling the remainder of the week. Zero isotherm is
over the northwest Arctic Coast this morning, and will be pulled
south behind the low to lie from Wainwright to Selawik to
Shaktoolik to Gambell by Tuesday morning, and from Deadhorse to
Livengood to Russian Mission to St Matthew Island by Wednesday
morning.

Surface...Broad areas of low pressure remain over the state with
a weak ridge over the western interior this morning. A 994 mb low
in the western Gulf of Alaska will wobble around through Tuesday
night and be near Dixon Entrance in southeast Alaska by Wednesday
morning. A 1006 mb low will develop in the weak leeside troughing
north of the Alaska Range this morning over the upper Tanana
Valley and move north to the upper Yukon Flats by Tuesday morning.
The weak ridging over the Western interior this morning will be
squeezed out today as 1002 mb low and weather front move east
across the Chukchi Sea and merge with the broad area of low
pressure that lies south and east of the Yukon River creating
broad low pressure over most of mainland Alaska. The 1002 mb low
will move over the Brooks Range and merge with the low over the
upper Yukon Flats Tuesday evening, then move northeast to
Demarcation Point by Wednesday morning, stalling just off the
coast through Wednesday night before merging with a low near Banks
Island. A 1017 mb high will move over Wrangel Island Tuesday with
ridging extending south over St Lawrence Island to Unimak Island.
The ridge will split south of St Lawrence Island Wednesday as a
994 mb low moves east across the Bering Sea to Bristol Bay by
Thursday morning.

Arctic Coast and Brooks Range...Not looking for much change
across the area. Cloudy, some fog, some showers primarily over the
northwest coast. Open water continues to moderate temperatures in
the coastal areas, but cooler temperatures for the inland
locations. Fog may be dense at times with poor visibility, but not
expecting any lengthy periods of poor visibility. Onshore flow
will continue for most areas with northeast to east winds at 10 to
20 mph prevailing, winds will swing around to northwest to north
on the northwest Arctic Coast tonight and eventually swing around
over most of the area by Wednesday morning. With those north winds
will be cooler temperatures, and falling snow levels. There is
potential for several inches of snow above 2000 feet in the Brooks
Range Tuesday, but not expecting it all to stick as some will
melt with ground temperatures remaining above freezing.

West Coast and Western Interior...Rain or showers moving over
much of the area today and some areas north of Norton Sound could
see up to one half inch of rain by Tuesday afternoon. Patchy fog
across the area, and some dense fog possible in the Bering Strait
and on St Lawrence Island this morning. Southwest winds
diminishing today and becoming northwest to north over the Chukchi
Sea, Bering Strait, and eastern Bering Sea as the front moves
east. High surf developing tonight as persistent northwest to
north winds develop over the Chukchi Sea. Will issue High Surf
Advisory for tonight through Tuesday evening for area from Cape
Espenberg west on the Chukchi Sea Coast. Temperatures slightly
warmer today for most of the area, then cooling as the week goes
on.

Central and Eastern Interior...Decreased shower activity over the
interior, but mostly cloudy to cloudy conditions will continue
for areas east of Manley Hot Springs. Temperatures a bit warmer
today with highs in the 60s again. Winds generally light. Slight
chance of thunderstorms this afternoon and evening, but mainly
over the upper Yukon Flats.

&&

Coastal Hazard Potential Days 3 and 4...Low will move to
Demarcation Point Wednesday and stall over the Beaufort Sea with
persistent north winds creating potential for High Surf over the
central Arctic Coast Thursday.

&&

.FIRE WEATHER...Slight chance of Thunderstorms this afternoon and
evening north and east of Fairbanks. Decreased showers activity
today, but more showers on the way Tuesday afternoon. Chance of
wetting rain low today. Relative Humidity values remain high and
will generally be above 40 percent. Sustained winds less than 15
mph.

&&

.HYDROLOGY...Rivers steady or trending down the next couple days.
Flood Advisory continues for the Tetlin Road, for the latest
information go to www.weather.gov/fairbanks.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

High Surf Advisory for AKZ207.

Flood Advisory for AKZ224.

Small Craft Advisory for PKZ200-PKZ210-PKZ220-PKZ225-PKZ230-
PKZ245.

&&

$$

SDB AUG 17


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