textproduct: Fairbanks

SYNOPSIS

Another fairly active day across Coastal and Mountainous regions of Alaska while much of the interior remains quiet. An extended period of Blizzard conditions has begun across the Arctic Coast and will persist for the next several days due to strong northeast winds and blowing snow. The prolonged high wind event continues for parts of the West Coast and Bering for the next 24 hours before the area of strongest winds shifts north of the Bering Strait. Heavy snow has been going largely according to forecast within the Eastern Alaska Range and Upper Tanana Valley. A narrow band of heavy snow stretching from around Eagle down to Isabel Pass may lead to locally higher snowfall amounts this evening, especially within the mountains. A warming trend has begun from southeast to northwest across Northern Alaska as increasing clouds and southerly flow bring surface temperatures back towards normal in the single digits above and below zero. Most cold weather, wind, and snow products expire over the next 12-18 hours while watches and warning continue along the Arctic and NW Coast. Relatively benign conditions set up over the majority of Northern Alaska later this week and into the weekend with near normal temperatures and dry conditions.

KEY WEATHER MESSAGES

Central and Eastern Interior...

- Winter weather headlines in effect for the eastern Alaska range passes and Upper Tanana Valley through tonight as snow increases from the southeast. Highest accumulations within Alaska range passes.

- Temperatures moderate through the end of the week with highs in the single digits above zero. The increasing sun angle brings a return to daily diurnal temperature curves.

- Winds ramp up across higher elevations, peaking today and Wednesday as a Tanana Valley Jet sets up near Delta Junction and southerly gap winds increase through Alaska Range Passes.

West Coast and Western Interior...

- A prolonged high wind event ongoing across Western Alaska and the Bering with wind gusts of 45-70 mph where warnings are in effect. Near Blizzard conditions will continue at times near the Bering Strait and for the NW Coast. - Temperatures begin to moderate Wednesday afternoon back toward zero and the single digits as the main core of cold air moves west over the Bering Sea.

- Light snow south of the Seward Peninsula Wednesday and Thursday with accumulations less than 1 inch.

North Slope and Brooks Range...

- Another round of Winter Storm Watches for blizzard conditions have been issued from Utqiagvik to Kaktovik along the Arctic Coast. Expect blizzard or near blizzard conditions from late this evening through Thursday morning.

- A prolonged high wind event continues for the NW Arctic Coast with gusts up to 60-70 mph through Thursday. Blizzard conditions at times from Kivalina to Point Hope.

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

- Temperatures begin to moderate Wednesday with most areas seeing temperatures between 0 and -20 F through the weekend.

FORECAST ANALYSIS AND DISCUSSION

A complex meteorological set up remains in place over Alaska bringing a wide range of weather conditions to different parts of the state. A 495dm upper low has been influencing the state for the past several days, bringing a much colder arctic airmass to the region. This upper low is finally shifting towards the West Coast and will make its way westward into the Bering by tomorrow. Southerly flow setting up on the back side of the low are in addition to increasing moisture advection from the Gulf are working to kick out the arctic airmass in place. This sets the stage for lows in the Gulf to bring energy and moisture northward to portions of the Eastern Interior, increasing wind and snow chances near the Alaska Range today and tomorrow.

Wind: At the surface, an anomalously strong 1055mb+ Arctic high remains in the high arctic while lower pressure in the Bering and Pacific result in a tight northerly pressure gradient across the state. This set up has led to blizzard conditions from high winds and blowing snow across portions of the West Coast, NW Coast, and Arctic Coast. As lower pressure moves into the Bering, the high wind and blizzard threat shifts northward, north of the Seward Peninsula by tomorrow. However, expect this same pattern to remain in place across far Northern Alaska through the end of the week where Blizzard Warnings remain in effect.

Southerly flow has begun within the Alaska range passes and in portions of the Tanana Valley as a low in the Gulf swings a front from the southeast into the area. A strong southerly gradient across the Alaska Range and 700mb jet of 40-55kts will lead gusty winds through the Eastern Alaska Range Passes and Delta Junction over the next 24 hours. Towards Thursday and the end of the week, the gradient and mid level jet become more easterly and less favorable for strong winds in this region, therefore expect much light flow for the end of the period.

Snow: Focusing on the far Eastern Interior toward the Yukon border, Upper Tanana Valley and Eastern Alaska range for the snow portion of the discussion. Satellite imagery shows a SW to NE oriented front extending from the Gulf northeast into the Yukon with a wave along it moving into Prince William Sound. A unique meteorological set up has lead to a slow moving band of heavy snow to move west across the eastern interior and Alaska range today. Aloft, a coupled jet has placed the region in an area of enhanced upper level divergence and lift. A quasi stationary boundary on the SE side of the upper polar low has been the focus for snow shower development in this region over the past 24 hours as Gulf moisture advects northwest into the region over the boundary. At the same time, the frontal boundary and associated wave pushing in from the Gulf is working to increase lift locally and enhance snow development. RAOB soundings from Fairbanks and Whitehorse today show steep mid and upper level lapse rates above a strong low level inversion. The incoming front and southerly flow have saturated the area above the inversion and dendritic growth zone, creating an environment conducive for heavy snow. With enhanced lift in the same region, a narrow band of heavy snow has formed from the Central Yukon to near Eagle to Delta Junction to Isabel Pass. This band has resulted in 1/4 mile or less visibility at times and high snowfall rates. This can also be seen on satellite based snowfall products such as AK-SFR imaging, confirming the presence of the band. Expect periods of heavy snow through the Upper Tanana Valley and Eastern Alaska range to continue over the next several hours as the band slowly works north and west. While this band will make its way towards Fairbanks, increasing southerly winds through the Alaska range may enhance downsloping the north. This band should weaken some as it interacts with mid level dry air closer to Fairbanks, resulting in lighter snow and only minor accumulations around Fairbanks and in areas that are more prone to downsloping off the Alaska Range.

Temperatures: Increasing clouds from the southeast and southerly flow will quickly eradicate the arctic airmass over the state. A significant warming trend occurs aloft the next 24 hours with 850mb temps rising from the -20s to +0s in a short amount of time. With upper ridging building in from NW Canada and low level easterly flow setting up through the end of the week, the mild airmass is expected to remain in place through the weekend with highs near to above normal in the single digits...maybe even low teens.

EXTENDED FORECAST DAYS 4-7

Benign conditions persist over the Interior and much of the West Coast into the extended period, however there are signs on the horizon of a more active pattern setting up around the day 7 period and beyond. The polar low responsible for the arctic air pushes off into Russia while weak upper ridging extends from Northwest Canada into the Interior. The trajectory and orientation of the ridging overhead should keep the numerous waves and lows in the Gulf in southern and southwest Alaska. Easterly/southeasterly flow persists at the surface into the weekend with well above normal 850mb and surface temperature anomalies. Overall relatively mild and dry conditions persist for the interior

The most active region in the extended will be the Arctic and NW Coast which will be under the influence of a polar airmass and the strong 1050mb+ arctic high. The northeasterly pressure gradient remains tight next week with an intense low level jet setting up along the coast Sunday through the middle of next week. Periods of high winds and near Blizzard conditions persist in this area with this set up with Point Hope and surrounding areas likely dealing with the worst conditions through the period. Despite a brief warm up this weekend, expect colder air with double digits below zero temps for next week. Periods of snow and snow showers remain in the forecast for the Brooks Range as waves of energy drop down from the high arctic this weekend and next week.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Blizzard Warning for AKZ801. Winter Weather Advisory for AKZ849. Winter Storm Warning for AKZ850. Extreme Cold Warning for AKZ813. Blizzard Warning for AKZ815. High Wind Warning for AKZ820-821-827. Cold Weather Advisory for AKZ803>805-808. Winter Storm Watch for AKZ803>805. Winter Storm Warning for AKZ832. Extreme Cold Warning for AKZ806-807. PK...Brisk Wind Advisory for PKZ801. Brisk Wind Advisory for PKZ802-803. Brisk Wind Advisory for PKZ804-852-853. Brisk Wind Advisory for PKZ805-809. Gale Warning for PKZ806-807. Gale Warning for PKZ810-814-816-817-851-854-856-857. Storm Warning for PKZ811. Gale Warning for PKZ812-858-861. Gale Warning for PKZ813. Gale Warning for PKZ815-860. Gale Warning for PKZ859.