textproduct: Fairbanks

SYNOPSIS

The next round of Arctic air is already entering Alaska from the northeast and will continue to engulf the rest of the state over the next 24 hours. Widespread double digit below zero temperatures as low as -20F to -50F are expected to fill in regionwide through Tuesday, with even colder wind chills. Northerly and northeasterly gap winds substantially increase tonight and persist into Wednesday across the Brooks Range, along the West Coast, and into the Bering Strait where winter weather and high wind headlines are already in place. As these winds usher in the incoming arctic airmass, wind chill values fall into the -50 to -75 range across much of the North Slope, prompting the issuance of widespread Cold Weather Advisories and Extreme Cold Watches. More sheltered locations within the Interior may not see such strong winds or as cold wind chills, however still expect air temperatures to plummet into the -20 to -45 range through Wednesday.

Snow chances through Monday will remain confined to the Southeast Interior and North Slope/Brooks Range, ahead of a more organized push of moisture Tuesday into Wednesday expanding those chances areawide out of the southeast. Winter weather advisories and warnings have been issued for the Eastern Alaska range passes and the Upper Tanana Valley, with highest snowfall amounts within the passes on Tuesday. A Blizzard Warning has been issued for the Northeast Arctic coast for Monday where several inches of new snow and wind gusts to 60 mph will make for dangerous travel and whiteout conditions. Scattered snow showers overspread the interior from the Southeast Tuesday and Wednesday as flow switches around to the southeast. Expect a warming trend closer to near normal for this time of year after Wednesday with highs reaching the single digits above zero. Clearing skies overnight should still lead to colder overnight lows as radiational cooling allows lows to fall below guidance in the zero to -20 range.

KEY WEATHER MESSAGES

Central and Eastern Interior...

- Winter weather headlines posted for the eastern Alaska range passes and Upper Tanana Valley Monday and Tuesday as snow increases from the southeast. Highest accumulations within Alaska range passes.

- Temperatures trend colder through Wednesday with coldest valley locations reaching down to -30F to -45F

- Winds ramp up across higher elevations, peaking on Tuesday and Wednesday as gusty winds expand to the Middle Tanana Valley around Delta and through Alaska Range Passes.

- Warmer temperatures will also build in midweek, returning to more seasonal levels to finish out the week as drier conditions prevail Thursday onward.

West Coast and Western Interior...

- A prolonged high wind event beginning across Western Alaska, with wind gusts of 30-60 mph becoming widespread along the West Coast and in the Bering where High Wind Warnings are in effect. - Temperatures plummeting back below zero through Thursday with lows -10F to -30F and even colder wind chills.

- More widespread light snow chances will build in regionwide southeast to northwest late Tuesday into Wednesday, shifting to the West Coast for Thursday, as warner temperatures also work back in mid to late week.

North Slope and Brooks Range..

- Wind gusts up to 60 mph and light snow are expected tonight into Monday for the Eastern Beaufort Sea Coast where a Blizzard Warning is now in effect.

- Widespread double digit below zero temperatures expected to fill in regionwide through midweek. Coldest locations are expected to drop to around -30F to -50F.

- Cold Weather Advisories and Extreme Cold Warnings have been expanded to include all of the Brooks Range and North Slope through Wednesday for wind chills as cold as -55 to -75F.

- Winds remain elevated through midweek with gusts up to around 30-50 mph, peaking for most Tuesday into Wednesday. A High Wind Watch has been issued for the NW Arctic Coast where gusts up to 70 mph remain possible Tuesday through Wednesday night.

FORECAST ANALYSIS AND DISCUSSION

A significant pattern change is underway for all of Northern Alaska as a polar airmass moves into from the Northeast bringing a several day stretch of significantly colder temperatures, strong winds, and dangerous wind chills. A 1050mb+ surface high sets up over the high arctic and Siberia, while a polar surface low nears the northeast arctic coast and another low pressure sets up in the north Pacific. This sets the stage for a strong northeasterly outflow event across most of Northern Alaska tonight and persisting into the middle of next week. Strong cold air advection causes 850mb temperatures to plummet quickly into the minus 20C to 35C range over the North Slope, with that same airmass filtering south of the Brooks range into early next week. Sub-zero highs have already expanded across the Interior today and will push further south and west by tomorrow. An arctic airmass this deep supports surface temperatures as low as -50F or lower for the North Slope and in the -25F to -45F range over the interior, with Tuesday being the coldest day of the week.

A tightening pressure gradient and stronger winds aloft will lead to increasing surface winds over the coming days... particularly along the Arctic/West Coasts and across higher elevations. The upper polar low tracks southwest towards the Bering Sea by midweek, maintaining strong winds through Tuesday as strongest winds ultimately shift north Tuesday night into Wednesday. Winds in stronger corridors along the coasts and higher elevations will see wind gusts around 30- 50 mph, locally stronger up to 60-70 mph especially for the NW Arctic Coast southwest to St. Lawrence Island. A mix of warnings and watches have been issued to capture where strongest winds are expected through midweek. Confidence has increased in widespread dangerous wind chills across the Brooks Range and North slope, therefore Cold Weather Advisories and Extreme Cold Watches have been expected across that region to account for wind chills in the -60F to -75F range through Wednesday. Additionally, will be monitoring the blowing snow potential for the arctic coast as additional winter weather products may be needed for Tuesday for low visibility and near whiteout conditions. On Tuesday, there is also increasing potential for strong gap winds to fill in through the Alaska Range Passes and across the Middle Tanana Valley around Delta Junction with wind gusts in excess of 40-50 mph possible.

Snow chances through Monday remain confined to the Eastern North Slope/Brooks Range and Southeast Interior, ahead of a regionwide expansion Tuesday into Wednesday. As the upper polar low descends over the state from the high arctic, flow switches around to the south in the Upper Tanana Valley and Eastern Alaska range allowing for moisture advection from the pacific northward into the region. A mid level frontal boundary on the southside of the polar low remains nearly stationary over the Upper Tanana Valley and is the focus for scattered snow showers in that region. As moisture advection increases the next 24 to 48 hours, the region will also be in an area of enhanced lift in the entrance region of a jet streak aloft. This in addition to waves of energy advecting in from the south will result in widespread snowfall accumulations within the Eastern Alaska range and Upper Tanana valley. Winter Weather products have been expanded for these areas to include Northway and Tok and through Isabel Pass. Highest snowfall amounts upwards of foot expected within the mountains and passes, with lower amounts 2-7 inches within the upper Tanana Valley.

The track of an upper level low over Northern Alaska towards the Bering Sea will advect moisture from the Gulf of Alaska during this timeframe, tapping into a larger plume of moisture from a series of stronger surface lows in the Pacific.. As a result, snow shower chances expand regionwide southeast to northwest Tuesday into Wednesday. Snowfall accumulations should be confined to the southeast portion of the state where winter weather headlines are in place with lighter snow showers and only minor accumulations for the interior midweek. Downsloping off the Alaska range will keep conditions much drier in portions of the eastern interior and around Fairbanks.

EXTENDED FORECAST DAYS 4-7

Active weather continues into the extended across all of Northern Alaska as an upper polar low traverses the state and moves off into the Bering Wednesday through the end of next week. As the polar low heads west, the next pattern change begins as southeasterly flow sets up across Eastern Alaska bringing increased moisture and warmer temperatures back northward. The arctic airmass quickly retreats into Siberia with a significant increase in 850 mb and low level temperatures, aided by downsloping off the Alaska range. During this time, numerous systems work there way into the Gulf of Alaska, sending waves of energy northwestward into the interior. Expect an increase in snow shower activity each day beginning Wednesday through end of the week. Downsloping off the Alaska range will likely keep areas just north of there, including Fairbanks, fairly dry with the most widespread snow showers in higher elevations and throughout the Central Interior. Max temperatures rise above zero for many locations by the end of the week with larger diurnal ranges and sub zero lows as clearer skies at night allow for good radiational cooling. Fairly dry conditions set up for the end of the week and into the weekend as the main storm track remains over the Pacific and Southern Alaska while subtle downsloping off the Alaska range persists.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...High Wind Watch for AKZ801. Cold Weather Advisory for AKZ809-811. Winter Storm Watch for AKZ850. Cold Weather Advisory for AKZ812. High Wind Warning for AKZ820-821-827. Winter Storm Watch for AKZ832. Blizzard Warning for AKZ805. PK...Brisk Wind Advisory for PKZ801. Brisk Wind Advisory for PKZ802-804-805-810-811-850-852-853-857. Brisk Wind Advisory for PKZ803. Gale Warning for PKZ806-807-856. Brisk Wind Advisory for PKZ813-858. Brisk Wind Advisory for PKZ814. Gale Warning for PKZ815. Gale Warning for PKZ816-817-851-854. Brisk Wind Advisory for PKZ859. Brisk Wind Advisory for PKZ860. Gale Warning for PKZ861.