Weather Service Report


162 
FXAK69 PAFG 162318
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
318 PM AKDT Mon Oct 16 2017

.DISCUSSION...

Models...Trending toward colder pattern next couple days. 
Initialized well against the 16/18Z surface analysis. Run to run 
solutions remain very good in the short term and midrange. Some 
significant discrepancies in the extended periods over the 
Aleutians that will need to be worked out over time. Models have 
handled the low dropping out of the high Arctic similarly with not
much spread in location or strength. Temperature guidance is not 
very good, and in particular is not handling low temperatures well
since many areas remain snow free on the ground. Will utilize a 
blend of the solutions for precipitation and will lean on 
continuity for temperatures but need to make some changes to match
current trends.

Aloft...At 500 hpa...Stacked low that has been over the Gulf of 
Anadyr the last few days continues to weaken and will eventually 
merge with the low dropping out of the Arctic. The low dropping 
out of the Arctic is 100 nm north of Banks Island at 495 dam and 
will move southwest to be over Point Barrow by Thursday morning at
496 dam, and over the Seward Peninsula by Friday afternoon at 500
dam. Ridging west of 160W in the Arctic and over the Chukchi Sea 
will continue to be pushed west as the low moves southwest and 
will be west of 180 by Tuesday evening. Weak ridging over the 
southwest mainland with a 525 dam center will continue to weaken 
and move east tonight and merge with ridging over the Gulf of 
Alaska. A shortwave associated with the Arctic low is moving over 
the Arctic Coast this afternoon and will continue to rotate around
the low. A second shortwave will move to the coast on Tuesday 
afternoon, and a third on Wednesday morning. A 513 dam low over 
the central Aleutians will move rapidly east through Thursday 
then dissipate over the southeast Panhandle. At 850 hpa...Zero 
isotherm south of the state. The low over the Canadian Archipelago
continues to spin colder air south and the -10 isotherm lies from
Dawson YT to Anaktuvuk Pass to Cape Lisburne this afternoon, and 
will lie from Dawson YT to Bettles to Teller and west by Tuesday 
afternoon. By Wednesday morning it will lie from Chalkyitsik to 
Monday morning. By Tuesday morning it will lie almost entirely 
south of out forecast area. The -20 isotherm approaches the 
central and eastern Arctic Coast Wednesday.

Surface...Weak high pressure over southwest mainland and eastern 
interior will weaken and pull back over the northeast Pacific and 
Yukon Territory. Weak high pressure over the western Brooks Range 
will pull back to the west. A weak trough over the Seward 
peninsula extends east over the upper Yukon Flats and will 
continue to expand as broad area of troughing develops between the
991 mb low near Banks Island, and the 975 mb low over the western
Aleutians. The low near Banks Island will remain stationary 
through the evening, then move north Tuesday rotating west then 
south to be over Point Barrow by early Thursday morning. A rapidly
developing low 500 nm north of Point Barrow will move to 150 nm 
north of Point Barrow by Tuesday morning at 998 mb and over the 
central Arctic Plain by Tuesday evening. High pressure west of 
160W and over the Chukchi Sea will weaken and be pushed west as 
the low drops out of the Arctic to the coast. The low in the 
western Aleutians will move to 100 nm south of Cold Bay by Tuesday
morning, and into the northeast Pacific tuesday night. The low 
over Banks Island will continue to move south after moving over 
the coast Thursday and will be over Kotzebue Sound by Thursday 
afternoon at 993 mb. 

Arctic Coast and Brooks Range...Could be very interesting Tuesday
as the low sitting high in the Arctic moves to the Central Coast.
Winds will increase from Point Barrow west and Winter Weatehr 
Advisories remain in place for zones 201 and 202. Conditions will 
be improving on the eastern Arctic Coast by morning. Snowfall 
amounts 2 to 4 inches but may be up to 6 inches depending on 
development of the low and how much moisture it will pick up. The 
open water factor, no sea ice within 500 nm of most of the Arctic 
Coast, will have unknown impact on the moisture values. Northwest 
winds 5 to 15 becoming north 10 to 30 mph with the strongest winds
between Point Lay and Point Barrow.

West Coast and Western Interior...Quiet period overall. Some
Sprinkles or flurries with mostly cloudy conditions. Patchy fog
along the rivers in the morning. Winds generally variable to 10 
mph through Tuesday. Temperatures slightly cooler. 

Central and Eastern Interior...Cloudy with some flurries this 
evening, then some light snow developing early Tuesday morning 
with up to 2 inches of snow possible. Heaviest snow will be in the
White Mountains and Upper Chena River Basin east of Two Rivers. 
Patchy fog. Generally light winds. Temperatures will continue the
cooling trend with lows falling to around 20 and high around 30 in
Fairbanks and vicinity. Coldest temperatures will be north of the
Yukon River where lows will fall to zero to -10. Much cooler 
temperatures for the end of the week through the weekend across 
the area.

&&

Extended forecast for days 4 to 7...Saturday through Monday models
remain in good agreement. They are currently having issues with
the potential of an extra tropical system being caught in the flow
and moving rapidly over the Aleutians.

&&

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

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

Winter Weather Advisory for AKZ201-AKZ202-AKZ204.

Heavy Freezing Spray Warning for PKZ240-PKZ245-PKZ505-PKZ510.

Small Craft Advisory for PKZ240-PKZ245.

&&

$$

SDB OCT 17

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Western Regional Climate Center, wrcc@dri.edu