Area Forecast Discussion
Issued by NWS Fairbanks, AK

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000
FXAK69 PAFG 292226
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
226 PM AKDT Mon May 29 2017

.DISCUSSION...

Models...The same general trend continues with the models doing
relatively well over the first 90 hours or so, then patterns
diverge quite significantly. For the 29/12Z solutions, that trend
continued. They initialize well against the 29/18Z local surface
analysis, but after 54 hours the begin to diverge, and by 96
hours they have very different solutions. Will be using a blend
for the first 72 hours this cycle, then will look at a more means
based blend for the extended periods to soften some of the bumps.

Aloft...At 500 hpa...Ridging over the central and eastern
interior will weaken and be pushed north and east as a 532 dam low
over Cook Inlet moves north over Lake Minchumina this evening,
then north over Anaktuvuk Pass by Tuesday morning as it weakens to
539 dam. A shortwave lies from the low south today and will move
to lie from Anaktuvuk Pass to Central to Glennallen to Cook Inlet
by Tuesday morning. The low and shortwave will sync up with a
532 dam low and shortwave over the Chukchi Sea that will drift
slowly north tonight, then to 250 north of Wrangel Island by
Wednesday morning. The combined wave will lie from Near Wrangel
Island over Barrow to Fort Yukon to Valdez by Tuesday afternoon,
moving north and east out of the state late Wednesday morning.
Ridging will build west across the southern half of mainland
Alaska Tuesday night, then over interior Alaska by late Thursday.
At 850 hpa...Zero isotherm lies from Barrow to Huslia to Yakutat
this afternoon with the temperature over Fairbanks around +4C. By
Tuesday afternoon it will lie from Deadhorse to Atigun Pass to
Unalakleet to Emmonak with the temperature over Fairbanks around
+1C. And by Thursday it will lie over the crest of the Eastern
Brooks Range to Ambler to Nome and over the eastern Bering Sea
with the temperature over Fairbanks around +6C. Temperatures will
continue to slowly warm into the weekend.

Surface...Broad thermal trough over interior Alaska with several
minor centers. Ridging over the arctic will persist as a low
develops over the arctic plain and moves over Barrow by Tuesday
morning at 1007 mb. This will tighten the pressure gradient over
the eastern arctic and Beaufort Sea as the low continues to move
northwest. The thermal trough will break down as energy is pulled
north into the arctic, and this will allow the 1018 mb high over
the southcentral area to build into the interior Tuesday night.
The thermal trough will redevelop in the upper Tanana Valley
Wednesday. By Wednesday night Ridge of high pressure will lie over
the arctic coast from the Chukchi Sea over the Canadian coast,
with a trough of low pressure over the arctic and another over the
Gulf of Alaska Coast, Bristol Bay, and the Aleutians. Easterly
flow will develop across the interior with warmer, more moist air
moving through the area.

Arctic Coast and Brooks Range...Potential for a very mixed bag of
precipitation tonight as some warmer air moves north over the
area spreading snow and rain showers to the area with a good
chance of freezing rain as surfaces cool. Not looking for
significant accumulation of ice as there will be a good mixture of
precipitation and most surfaces are at or near freezing for most
hours during the day. Front will move through tonight and
northeast winds will diminish and become southwest to west for
most locations and diminish from around 20 mph to less than 10
mph. With high pressure building over the area Wednesday there
will be some sunny days to end the week. Temperatures will be
slowly rising, and the coastal areas could see highs in the low
40s this weekend.

West Coast and Western Interior...Looks like it will be a very
nice week, especially in the coastal areas as surface ridging
builds out of Siberia over the west coast. Some isolated
thunderstorms and showers in the interior locations through
Tuesday, then again this coming weekend as the atmosphere becomes
more unstable. Temperatures warming through the week and there
could be some highs in the 60s along the coast south of the Bering
Strait later in the week, while inland areas will reach the upper
60s by late in the week, and there may even be some 70s for highs
Saturday. Winds 5 to 20 mph tonight will be diminishing and be
less than 10 mph for most areas the remainder of the week, the
exception will be the outer Capes where winds to 20 mph will
persist.

Central and Eastern Interior...Cloudy this evening with a few
sprinkles around the interior, but no significant rainfall
tonight. As the shortwave aloft moves north clearing Tuesday
across the interior with partly cloudy conditions prevailing into
Friday. Some afternoon fair weather cumulus Tuesday through
Thursday, but the atmosphere looks pretty stable for now. That
will change Friday as we return to a more convective pattern with
afternoon Thunderstorms and showers possible and the potential for
some easterly wave activity coming out of Canada. Gap flow winds
gusting to around 40 mph in the eastern Alaska range today will
taper off this evening. Winds for the remainder of the area will
generally be less than 10 mph with occasional gusts to around 15
mph during the day. There is of course and exception, but this
time it is for the upper Yukon Flats where west winds of 10 to 20
mph will develop Tuesday night and diminish Wednesday.
Temperatures a bit cooler through Tuesday, then warming through
the remainder of the week with highs for many areas south of the
Yukon River around 70 by the end of the week.

&&

.FIRE WEATHER...Remains quiet for the moment, but expect it to
pick up later in the week as we see more seasonal convective and
drier conditions for the Central and Eastern Interior. Relative
humidity values through Thursday will fall to 20 to 30 percent
during the afternoon hours for many locations, but winds will
generally be light, and not expecting much if any thunderstorms
activity until at least Friday.

&&

.HYDROLOGY...All the rivers and streams in the the interior are
trending down, and no significant rainfall or snowpack melting is
expected. In the arctic drainages, low flow continues in some of
the drainages with water continuing to pond in the frozen
drainages, with no immediate concerns as breakup trudges on.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

Brisk Wind Advisory for PKZ235-PKZ240-PKZ245.

&&

$$

SDB MAY 17



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