textproduct: Fairbanks

SYNOPSIS

Cold weather continues across most of Northern Alaska, but that will change later this morning and through the weekend as a low moves off of Siberia. The low will shift east and move along the Arctic coast from west to east, bringing widespread snowfall of at least an inch with much warmer temperatures to most of Alaska north of the AK Range. On the North Slope, winds will increase significantly today as the low moves in, which could result in blowing snow and reduced visibilities at times, especially where they combine with falling snow. Early next week, while there is uncertainty due to potential snow and cloud cover in the area, very cold conditions over the region could drop temperatures into the -40s or colder at times across much of Eastern Alaska, even outside typical cold spots.

KEY WEATHER MESSAGES

Central and Eastern Interior... - This evening, a system will move into the area and yield snow totals widely reaching 1 to 3 inches through the weekend, with higher totals of over 4 inches possible from the north slopes of the Western AK Range to the White Mountains.

- Winds will begin to increase out of the north through Windy and Isabel Passes Friday afternoon and lasting through Saturday morning, with blowing snow and reduced visibilities down to 1/2 mile or less possible at times.

- Cold weather will subside today across the Interior as this system pushes out the cold air mass currently in place. Considerably warmer temperatures are likely on Friday, with highs widely rising into the positive single or double digits.

- Early next week, while there is uncertainty due to the chance for light snow or cloud cover, much colder air is going to settle back into the area, especially over the eastern half of the Interior. Some areas, such as the Yukon Flats and Upper Tanana Valley, could see temperatures drop enough to necessitate Cold Weather products.

West Coast and Western Interior... - From today through the weekend, much warmer temperatures are expected, with increasing clouds and around 2-6 inches of snow, with locally higher amounts farther north and inland over higher terrain. Winds will also increase with gusts approaching 35 mph around the Seward Peninsula and 50 mph from Kotzebue Sound and northwest. Pockets of sleet and/or freezing rain may mix with snow in the YK Delta/Norton Sound area as it begins to taper off late Thursday. - Temperatures will return to more seasonal values with initially drier conditions going into the early part of next week.

North Slope and Brooks Range... - Southerly winds will begin to increase through Anaktuvuk Pass ahead of the approaching low pressure system by late this evening. Ground blizzards and whiteout conditions are possible through Friday with these winds. They will shift westerly after passage of the front, which will allow them to weaken, but snowfall will likely continue through the weekend.

- Snow is expected to move in across the region going into the weekend as a low moves along the Arctic coast from west to east. 1 to 4 inches of snow are widely possible across the area. Higher totals are possible in the Brooks Range and Arctic plains, mostly east of the Dalton Highway. Portions of the eastern Brooks Range southeast of Sagwon may receive between 6-8 inches of snow.

- Through the weekend, widespread winds of 25 to 40 mph, with higher gusts, will shift from SW to W and could combine with falling/fresh snow to allow for blowing snow, which could reduce visibilities at times.

FORECAST ANALYSIS AND DISCUSSION

A broad ridge is extending from the North Pacific across the Bering Sea and into the Chukchi Sea, while general troughing is extending from the high Arctic/Canadian Archipelago southwest into Eastern Alaska. While cold air remains in place this morning across most of Northern Alaska, a low over Siberia will shift north into the Chukchi Sea later this morning before shifting eastward along the Arctic Coast. As it moves east, it will produce 1-3 inches of snow across most of Alaska north of the Alaska Range. Higher totals will be possible in parts of northwestern Alaska, the southern Seward Peninsula, and in the Arctic plains and eastern Brooks Range east of the Dalton Highway. An area extending from the western Alaska Range to the White Mountains may also see up to 4-6 inches of snow.

As the low shifts east, winds will significantly increase across the North Slope, with many areas seeing sustained winds up to 25 to 40 mph, with higher gusts. Parts of the eastern Arctic coast may see sustained winds approaching 50 mph. Where these winds combine with falling snow, they may result in blowing snow-induced visibility restrictions, potentially reaching blizzard criteria (especially on the eastern Arctic coast). Winter Storm Watches have been issued on this basis for Zones 804 and 805 from Nuiqsut east, with Winter Weather Advisories elsewhere. There will also be westerly winds across the Interior, which may result in blowing snow in the more elevated areas. In the Alaska Range, a Winter Weather Advisory is in effect--after initial west winds, the winds may turn to the north Friday afternoon resulting in a funneling effect in the passes, strengthening the winds there.

After the low exits the area Saturday morning, most snow and winds will fall off across the Interior, with colder conditions reconsolidating. The primary exception is the North Slope, which could see a series of lows moving into the area beginning Saturday night, each of which could drop light snow in the area and increase the winds/blowing snow again, especially on the eastern Arctic coast. A quick burst of snow is also possible on the Western Seward Peninsula, St. Lawrence Island, and the YK Delta coast on Saturday with a weak surface low/shortwave aloft.

EXTENDED FORECAST DAYS 4-7

From Monday through late next week, the ridge aloft will build into the central to northern Bering Sea, with extensive troughing across northwestern Canada. On the North Slope, a series of lows is possible on the North Slope moving in from over the Arctic, each of which may produce light snow and bring up the winds (and a possibility of blowing snow), especially on the eastern Arctic coast.

Elsewhere, while periods of very cold air are expected on Monday, there is increased uncertainty on the likelihood for snowfall or the persistence of the cold air in the area. While most models/ their ensembles support increased north winds with light snow over Western Alaska late Monday into Tuesday, some extend the snow as far east as the Eastern Interior, while others keep it farther west. This has a significant effect on cloud cover and temperatures, with the drier and clearer solutions being much more conducive to temperatures near or below -40F. The best confidence for such temperatures is on Monday, when temperatures at the 850 mb level across much of Eastern Alaska will range from -25 to -30C. Thereafter through most of the rest of the third week of December, model guidance suggests the periphery of the ridge aloft could shift into the Interior, pushing out the cold air, although the cold air could reconsolidate at times.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Winter Weather Advisory for AKZ801>803-806-807-813>824. Winter Weather Advisory for AKZ847>850. Winter Storm Watch for AKZ804-805. Winter Weather Advisory for AKZ808>810. PK...Brisk Wind Advisory for PKZ801. Brisk Wind Advisory for PKZ802-803-808-852. Brisk Wind Advisory for PKZ804. Brisk Wind Advisory for PKZ805-855. Gale Warning for PKZ806-817-854. Gale Warning for PKZ807-856. Gale Warning for PKZ809. Gale Warning for PKZ810. Gale Warning for PKZ811-857. Gale Warning for PKZ812-858. Gale Warning for PKZ813-859. Gale Warning for PKZ814-860. Gale Warning for PKZ815-861. Gale Warning for PKZ816-851. Heavy Freezing Spray Warning for PKZ817-854. Brisk Wind Advisory for PKZ850. Brisk Wind Advisory for PKZ853.