textproduct: Fairbanks

SYNOPSIS

Generally quiet weather will continue across Northern Alaska today, with light snow showers confined to the Eastern North Slope/Brooks Range and Eastern Interior. A cold, dense airmass remains on track to move southwest across our region Sunday through Tuesday with significantly colder temperatures, especially for locations further north and west where well above normal temperatures have been observed over the past several days. Widespread double digit below zero temperatures reaching down to around -20F to -45F are expected to build in regionwide early next week with even colder wind chills at times. Gusty winds will also accompany this cool down, with strongest winds expected across higher elevations and the West/Arctic Coast. Winds will remain elevated through midweek, as increasing southeasterly flow works to bring more widespread light snow chances and warming temperatures into the region.

KEY WEATHER MESSAGES

Central and Eastern Interior...

- Light snow will work north to south across the Eastern Interior today, continuing overnight and throughout the day on Sunday for the Upper Tanana Valley. Accumulations around a T-2" expected.

- Wind gusts of 20-40 mph will continue today through Alaska Range Passes and along the Yukon River at Eagle.

- Coldest valleys across the Interior will drop to -15F to -30F through the weekend, trending even Monday and Tuesday down to around -20F to -45F with even colder wind chills.

- Light snow chances will continue for the Upper Tanana Valley into early next week, with those chances expanding regionwide Tuesday into Wednesday as gusty winds and warmer temperatures build into the Interior.

West Coast and Western Interior...

- Quiet and dry conditions will continue today with areas of low stratus and dense fog (particularly along the West Coast), as temperatures trend colder over the weekend.

- Northeast winds steadily increase Sunday into Monday as a much colder airmass builds in, supporting the return of widespread subzero temperatures. Coldest locations are expected to drop to around -15F to -40F through midweek with even colder wind chills.

- Wind gusts of 30-50 mph will become widespread along the West Coast early next week, with locally stronger gusts up to around 60 mph possible offshore and at St. Lawrence Island. Winds are expected to remain elevated through midweek.

- Light snow chances will build in regionwide southeast to northwest Tuesday into Wednesday, as warmer temperatures also work back in mid to late week.

North Slope and Brooks Range...

- Light snow and wind gusts of 30-40 mph will continue today across the Eastern North Slope/Brooks Range, with additional snow accumulations of 1-3" and areas of blowing snow.

- Well above normal temperatures in place now will trend much colder over the weekend into early next week as a significantly colder airmass builds in, supporting the return of widespread double digit below temperatures. Coldest locations are expected to drop to around -20F to -45F with even colder wind chills.

- Gusty winds will continue through the Brooks Range early next week, expanding further Arctic Coast early to midweek with gusts around 30-50 mph. Winds are expected to remain elevated through midweek, strengthening regionwide tuesday into Wednesday.

- Isolated light snow showers will continue early next week, becoming increasingly scattered by midweek.

FORECAST ANALYSIS AND DISCUSSION

Saturday through Monday Night. Early morning satellite imagery shows a broad NW tilted upper level trough over Northern Alaska, as a 502 dm low centered in the western Canadian Archipelago steers a front south across the Interior. Light snow will continue across the Eastern North Slope/Brooks Range today, as the front shifts south along the Alcan Border through the Eastern Interior today into tonight. An additional 1-3" of snow is expected further northeast with around a T-2" for the Eastern Interior, heaviest along the Alcan Border. Elsewhere across the region, we are looking at a generally quiet and dry day with areas of low stratus and fog particularly along the West Coast.

High confidence continues to support that aforementioned 500 mb low in the high Arctic working southwest from the Chukchi Sea and NW Canada towards the Bering Sea early next week. This system will usher in much colder temperatures across region, with widespread double digit below zero surface temperatures expected as 850 mb temperatures around -20C to -35C build in. This airmass will work to support coldest locations dropping to around -30F to -50F with even colder wind chills. The apex of the widespread coldest conditions is favored to be Monday night into Tuesday morning. While temperatures will trend even colder in an already cold Interior, this will be a significant pattern change for locations further north and west where well above normal temperatures to finish out the week will see as much as a 40-60 degree cooldown.

Gusty winds will accompany this system as it tracks from the Chukchi Sea to the Bering Sea early next week given a tightening pressure gradient particularly along the West Coast. In this corridor, we will see winds steadily ramp up Sunday into Monday with gusts to around 30-50 mph, locally stronger up to around 60 mph offshore and at St. Lawrence Island. Winds across higher elevations and the North Slope/Brooks Range will also pick up during this timeframe, with these strong winds leading to areas of blowing snow and very cold wind chills. Snow chances Sunday and Monday will remain confined to the North Slope/Brooks Range and Upper Tanana Valley as predominant dry conditions prevail elsewhere.

EXTENDED FORECAST DAYS 4-7

Tuesday through next Saturday. Ensemble models continue to remain in fairly good agreement through the extended forecast, showing that aforementioned 500 mb low continuing its progression southwest across Northern Alaska into the Bering Sea by late Tuesday into Wednesday. This upper level setup will support prevailing southeasterly flow building into the Interior Tuesday into Wednesday, as moisture from the Gulf of Alaska lifts north over the Alaska Range with widespread light snowfall midweek and warming temperatures.

Strong winds will also continue through midweek with this pattern, especially along the North Slope, West Coast, and across higher elevations. This combination of cold air and gusty winds could easily lead to a period of dangerously cold wind chills midweek. Winds will be calmer for most part across the Interior as strong inversions will make it difficult for these winds to mix down to valley floors except where valleys and channels are open to the northeast. The exception to this will be the Middle Tanana Valley around Delta Junction where winds are expected to ramp up Tuesday as winds favor a more downvalley southeasterly flow. Where winds are stronger especially further south and west, temperatures will trend warmer versus areas that keep with lighter winds. Summit winds will be stronger, especially along the Dalton Highway Summits, in addition to along the Arctic/West Coasts. We will continue to monitor the potential and narrow down the corridors for any hazard product issuance where wind chills or blowing snow with these stronger winds will lead to hazardous conditions.

Winds will subside for most Wednesday into Thursday as strongest wind shifts north to the Arctic Coast. The low in the Bering Sea will strengthen once it can tap into warmer, more moist air around a low in the North Pacific. This will help to pull in a warmer airmass back across Northern Alaska, bringing temperatures closer to a seasonal normal to finish out the work week into next week as least isolated snow chances persist.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Winter Weather Advisory for AKZ805. PK...Brisk Wind Advisory for PKZ801-810-811-850-856-857. Brisk Wind Advisory for PKZ802-804-805-853. Brisk Wind Advisory for PKZ806. Brisk Wind Advisory for PKZ807. Brisk Wind Advisory for PKZ814-860. Brisk Wind Advisory for PKZ815. Brisk Wind Advisory for PKZ816. Small Craft Advisory for PKZ817. Gale Warning for PKZ851-854. Brisk Wind Advisory for PKZ861.