textproduct: Fairbanks

SYNOPSIS

Generally unsettled weather is expected the next several days. North to northeast winds on the Western Arctic Coast and through the Bering Strait are expected to continue today, although blowing snow potential will be limited. Several rounds of snow and rain will be possbiel across our area and will generally move in a southwest-to-northeast trajectory. While some areas of precipitation will continue in the Interior and across the Norton Sound area over the next couple days, a much wetter stretch of weather is expected from Saturday onward as a low begins to affect Western Alaska. Strong easterly winds will be possible from then through Saturday night over some coastal locations and across the northern Bering Sea as this occurs. A broad area of snow will be possible extending from the YK Delta and across the Western/ Central Interior, although some details are still uncertain.

KEY WEATHER MESSAGES

- High temperatures remain in the 30s and low 40s with low temps in the teens and 20s. Warmest temps are expected to reside in the Middle/Upper Tanana Valley.

- Scattered snow showers are expected to persist through this afternoon, especially north and west of Fairbanks with up to 1 inch of snow possible. Expect a half inch or less in Fairbanks.

- Light snow showers are expected again from tonight through the weekend with light accumulations expected.

- Heavy snow is expected in the Southern Alaska Range, particularly along the Richardson Highway this morning through Saturday afternoon. Winter Weather Advisory Issued. * Snowfall accumulations south of Trims Camp may be as high as 6 to 12 inches with up to 18 inches possible in the higher terrain, away from the road.

West Coast and Western Interior... - Breezy northeasterly winds will continue through at least Thursday with the strongest winds from the Bering Strait to St. Lawrence Island. Expected gusts up to 35 mph.

- Mixed rain and snow showers in the Western Interior valleys through Friday afternoon with mostly snow above 1000ft. * Snow amounts will be around 1 to 3 inches (most in the terrain) through Friday afternoon. * Another round of snow, heavier and steadier arrives Saturday afternoon.

- Similar temperatures are expected today compared to yesterday. A cooling trend arrives on Friday with highs in the teens and 20s from Shungnak to St. Lawrence Island. Highs in the low 30s from Nome to Hooper Bay and mid to upper 30s in the Interior. * Expect a continued cooling trend into Saturday with 20s to near 30 hanging on in the YK Delta, teens and low 20s north of there along the coast and upper 20s to mid 30s in the Interior.

North Slope and Brooks Range.. - Periods of gusty winds on the northwest Arctic Coast continue through the end of the week. Gusts as high as 45 mph are possible between Point Hope and Point Lay. Periods of blowing snow may reduce visibility but largely remain over 1 mile.

- Cold temperatures continue through the end of the week with highs in the single digits above zero while overnight lows reach as cold as the teens below zero.

FORECAST ANALYSIS AND DISCUSSION

An unsettled weather pattern will continue across Northern Alaska over the next several days. The period begins with a ~520 dm upper level low at 500 mb over the southeastern Bering Sea. This low is nearly vertically stacked with a weak surface low (~1004 mb) and is bringing some light snow showers to the YK Delta and Lower Yukon Valley. There is ridging on its east side focused over the Gulf of Alaska supporting southwest flow across the area and which will aid in a continuing progressive flow pattern. Some light snow showers are occurring in the Central/Eastern Interior with a weak front/shortwave moving through the area; given relatively dry air in the valleys, much of this is falling as virga. Arctic troughing (around 508 dm at 500 mb with 850 mb) will dip southward into the North Slope by this afternoon and gradually shift southward across Western Alaska. This will be associated with a fair amount of cold air, with 850 mb temperatures around 20C and will lead to cooling surface temperatures in some areas as it shifts south.

Moving into tomorrow/Friday, as the Bering Sea low moves inland, precipitation will diminish in the YK Delta and Lower Yukon Valley while spreading northward into the northwestern Interior. This precipitation will generally be light enough that regular diurnal warming could lead to snow transitioning to rain during the afternoon in some of these areas where it gets warm enough. By Friday evening, troughing will spread southward across Western Alaska, pushing the ridge east and flattening out its western periphery to have a more meridional orientation. This will support nearly due south flow across the Alaska Range, with gap winds through Isabel Pass and weak downsloping in the southern Interior. As this occurs, troughing moving into southcentral Alaska with substantive moisture will cross the Alaska Range. This will support scattered to numerous showers across the Central and Eastern Interior, with many of these showers being convectively- driven, especially in the higher terrain. Precipitation type could be diurnally-driven in the valleys, with rain more likely during the afternoon/evening hours. The southern side of the Alaska Range, especially on the eastern side, could see upwards of an inch of liquid-equivalent precipitation, which could add up to several inches of snow, even with some melting in the lower elevations. During this general time frame, high pressure north of Siberia shifts southeast, with an approaching ~970 mb low in the southern Bering Sea and weak low pressure over Alaska. This will support a northerly gradient wind strengthening through the Chukchi Sea and Bering Seas from Saturday into Sunday. The strongest winds will be in areas with very dry air, but preexisting snowfall could blow in some areas, although there is uncertainty.

Saturday afternoon and evening, a warm front on the leading edge of the Bering low will begin to move inland over the YK Delta, bringing brisk east to northeast winds to the northern Bering Sea. Over the open water, winds are likely to reach gale force. The strongest winds will likely occur over the western YK Delta and St. Lawrence Island. As the front moves inland, an expansive area of precipitation will extend across the southern YK Delta and the Western/Central Interior. There is a chance for blowing snow conditions in spots where high winds can combine with falling snow. Northerly winds on the west side of the low will help to pull cold air with the Arctic trough southward, dropping highs in much of Western Alaska below freezing through early next week. Moving into Sunday, the ridging over the Gulf/North Pacific flattens out, allowing for generally zonal flow across the area at the 500 mb level. While this is normally not conducive to southerly gap flow through the mountains, the 700 and especially 850 mb upper low over Western Alaska will have a nearly southerly gradient, with a 5 to 7 mb gradient across the mountains. This will permit breezy/gusty winds through the passes.

EXTENDED FORECAST DAYS 4-7

To start out the extended time frame, an extensive area of precipitation (mostly snow) will extend from the YK Delta northeast across western portions of the Interior. There is uncertainty on exactly how far east or west this area will be. A majority of model guidance places the band along an axis extending from the YK Delta to near Bettles, although a few outliers extend it in a more northward direction, reaching into the Western Brooks Range. Regardless, in the area of this primary band, liquid-equivalent precipitation could range from 0.2 to 0.5 inches. While the southern portions of this area could see some daytime transition to rain when it is warmest, most precipitation will likely fall as snow. While there is uncertainty on totals in part due to uncertain snow ratios, there is some model support for ratios of 15:1 or higher, which could potentially support over six inches of snow in many areas. Some light snow will also be possible over the North Slope beginning this weekend and running through early next week. By Monday, some of the precipitation in the Western/Central Interior could begin pushing into the Eastern Interior, with scattered snow/rain showers remaining possible through late in the week. During the midweek timeframe, cold air over Western Alaska could briefly intrude into the central and eastern parts of the state, which could drop highs even in the warmer valleys to near or below freezing.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Winter Weather Advisory for AKZ850. PK...Brisk Wind Advisory for PKZ806-807. Brisk Wind Advisory for PKZ810. Gale Warning for PKZ811-857. Brisk Wind Advisory for PKZ812. Small Craft Advisory for PKZ816. Heavy Freezing Spray Warning for PKZ816. Brisk Wind Advisory for PKZ817-854-856. Brisk Wind Advisory for PKZ851-858.