Area Forecast Discussion
Issued by NWS Fairbanks, AK

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FXAK69 PAFG 191149
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
349 AM AKDT Sat Aug 19 2017

.DISCUSSION...

Models...

Aloft...At 500 hpa...Long wave trough extends from high in the
Arctic to south of the Alaska Peninsula. A 534 dam low is over the
Dateline near 80N and will move east to 400 nm north of Point
Barrow by Sunday morning. A 535 dam low near 80N 1590W will move
north to the pole by Sunday morning. A 544 dam ridge lies over the
Arctic nearshore waters and will persist into Sunday morning then
drift over the coast. A 533 dam low over the Seward Peninsula
will move south over Anvik by Sunday morning, then dives south
over Kodiak Island Sunday evening as it moves over the north
Pacific spinning moisture north into the interior. A series of
shortwaves will move around the low as it moves south, but trying
to time the shortwaves is impractical. There will be one shortwave
that will move north across the Central and Eastern Interior this
evening. A 547 dam low will develop over the Central Brooks Range
Monday morning in the longwave trough, then move northeast over
Deadhorse by Tuesday morning. A ridge will build over the western
Bering Sea today, and move over the central Bering Sea by Monday
morning with 564 dam heights pushing north over the Gulf of
Anadyr. At 850 hpa...Temperatures over the West Coast not changing
much next 24 hours, then warming to around zero Sunday afternoon.
In the interior temperatures warming to around +5 Celsius by
Sunday afternoon. Zero isotherm currently lies from Deadhorse to
Kantishna to Bethel, and will pull back to the west to lie from
Nuiqsut to McGrath to Cold Bay, then north to St Lawrence Island
with the pool of cold air over the West Coast and Bering Strait
shrinking.

Surface...A very unsettled pattern remains over the state with
several lows spinning around and across the area into mid week. A
994 mb low 600 nm north of Point Barrow will move north to the
pole by Sunday morning. A 1009 mb high is over Point Barrow this
morning with weak ridging over the nearshore waters extending west
to a 1017 mb high over the Gulf of Anadyr. Weak ridging persists
over British Columbia and extends north to MacKenzie Bay. Several
lows are floating around over mainland Alaska with the primary low
a 1004 mb low over Kotzebue Sound that will move south and be
absorbed into a trough that lies from the Fortymile Country over
southcentral Alaska to a 998 mb low 200 nm south of Sand Point. As
the low moves east the trough over the Fortymile Country will
swing back to the west over the middle Tanana Valley by Sunday
morning and stall over the area. The low will continue to move
northeast to 100 nm southeast of Kodiak City, and a 1006 mb low
will develop over the Goodpaster River Basin Monday afternoon, and
a 1003 mb low will develop over the Upper Tanana Valley. The whole
system will be pushed east as ridging builds north and slides east
Tuesday.

Arctic Coast and Brooks Range...Stratus ceilings, areas of fog,
and drizzle or light rain will prevail. Fog will be dense at
times with poor visibility. Heaviest rainfall will be in the
Brooks Range, but most areas will see less than one quarter inch
of rain the next couple days. Temperatures not much different
today from yesterday, but slightly cooler overnight inland, then
slightly warmer. Winds generally northeast to east at 5 to 15 mph
increasing Monday to 10 to 20 mph for most areas.

West Coast and Western Interior...Showers and patchy fog will
continue across the area today into Sunday evening before it
tapers off a bit. No significant rainfall across the area, but
most areas will see less than one quarter inch with the heaviest
rainfall in the lower Yukon Delta around Anvik with up to one half
inch of rainfall possible. Winds generally north along the coast
at 10 to 20 mph, and southwest to west in the interior at 5 to 15
mph. Slight chance of Thunderstorms in the middle Yukon River
Valley, and in the upper Kuskokwim River Valley today and Sunday.

Central and Eastern Interior...Another day with showers in the
interior as the low out west continues to spin them into the area
with a good moisture feed from the south and upslope component
enhancing the rainfall. Rainfall amounts will range from up to
1.50 inches in the Alaska Range, to 3/4 of an inch around Central,
to a 1/4 inch around Fairbanks and along the Elliott and Dalton
Highways to Coldfoot today. Conditions remain unstable with Cape
values up to 1000 j/kg, and a negative lifted index over much of
the interior this afternoon and evening, and again on Sunday.
Thunderstorms will be isolated with potential for heavy downpours,
small hail, and some gusty winds. Winds over most of the area
will be light and variable, and temperatures will warm slightly
over the next few days.

&&

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

&&

.FIRE WEATHER...Isolated Thunderstorms and scattered showers will
continue over the area through the weekend. Chance of wetting
rain remains relatively high, but due to the nature of the rain
being showery, it will not occur over the whole forecast area.
Relative Humidity values remain high and will generally be above
40 percent. Sustained winds less than 15 mph.

&&

.HYDROLOGY...Rivers remain higher than they have been most of the
summer, but are trending down in most areas. Heaviest rainfall the
next 24 hours will be over the Alaska Range so expect streams and
rivers in those areas to continue to run a bit high, but well
within banks. Flood Advisory continues for the Tetlin Road, for
the latest information go to www.weather.gov/fairbanks.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

Flood Advisory for AKZ224.

Small Craft Advisory for PKZ210-PKZ220.

&&

$$

SDB AUG 17


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