textproduct: Fairbanks

SYNOPSIS

Unsettled weather continues across Northern Alaska. A front pushing into the area today will yield strong east to northeast winds across the West Coast, with an extensive band of precipitation bringing the potential for several inches of snow to the Western and Central Interior. In areas of the West Coast where strong winds can combine with fallen or falling snow, blowing snow conditions reducing visibility will be possible. Heavy snow is ongoing for the eastern Alaska Range south of Trims camp and will continue through this afternoon before diminishing. As the next round of precipitation with the front enters the Central/Eastern Interior, this heavy precipitation will pick up again, with slick conditions possible at times. There is some uncertainty on potential snow totals in the Middle/Upper Tanana Valley, but with showery activity in the area, up to a few inches could occur. Temperatures will be cooler in Western Alaska today but will recover tomorrow, with a more significant drop on Tuesday next week. The Central and Eastern Interior will also see temperatures fall to a lesser extent during the latter time frame. Another system will affect the area by the middle of next week, with more snow and mixed precipitation possible, especially in Western Alaska.

KEY WEATHER MESSAGES

Central and Eastern Interior... - Moderate snow is expected in the Eastern AK Range south of Trims Camp through this afternoon with another 3 to 6 inches of snow expected.

- More impactful weather arrives on Sunday as a front pushes snow, heavy at times to much of the Interior. The snow has a 40% chance to mix with rain Sunday evening into early Monday morning in the Middle Tanana Valley as temperatures rise near and above freezing. * Any rain changes back to snow on Monday resulting in a slushy mess of accumulations in the valleys. The higher terrain above 1000ft will likely remain all snow throughout the event. * Snowfall totals will range between 2 and 4 inches in the valleys with between 3 and 7 inches in the terrain around Fairbanks. * One important note is, if there is rain, it can lead to flooding or pooling/ponding of water since the ground is still frozen, leaving nowhere for the water to drain.

- Any wet/slushy spots will likely refreeze Monday morning and especially Tuesday morning as temperatures drop below freezing.

West Coast and Western Interior... - A front will bring very strong wind to most of the West Coast, with the strongest wind being in the Bering Strait, where northeast winds could gust up to 65 mph.

- This same front also provides snow beginning this morning in the Yukon Delta and gradually traversing north and east through tonight and Sunday. * Rain will likely mix with the snow in the Lower Yukon and Upper Kuskokwim Valleys from Mountain Village to McGrath with the best chances being Sunday afternoon through Monday morning. * Prior to the rain, snow amounts will be around 4 to 7 inches. North of the mixing line, snow amounts will range between 5 to 10 inches from Ruby to Kaltag (highest in Kaltag) and 3 to 6 inches in the Kobuk Valley.

- Any rain across the area will change back to light snow and snow showers Monday afternoon which will linger into Tuesday.

- Winds will also gradually weaken on Monday and Tuesday. Another system looks to move into the area on Wednesday.

North Slope and Brooks Range.. - Generally quiet weather on the North Slope with unseasonably cold temperatures continuing into next week.

- Light snow continues in the Central Brooks Range through this evening with only light accumulations around 1 to 2 inches expected. - Another area of snow arrives on Sunday, particularly late in the day and gradually traverses north to the coast Sunday night and Monday. * This second round of snow will bring another 1 to 3 inches in the North-Central Brooks Range with around 1 inch on the North Slope.

FORECAST ANALYSIS AND DISCUSSION

Active, unsettled weather continues through next week across Northern Alaska. Elongated troughing aloft from over the Arctic (with minimum 500 mb heights of around 512 dm) extends across the North Slope and the Seward Peninsula. At the 850 mb level, temperatures are around 22C at 850 mb over the North Slope and 15C over the Seward Peninsula. Cold air associated with this area of troughing along with northerly winds will permit colder surface high temperatures today in Western Alaska; highs on the Seward Peninsula/coastal areas are expected to be in the single digits and teens above zero, with highs in the Western Interior in the mid to upper 20s from around Galena north. Scattered showers continue across an area extending from Norton Sound to the Central Brooks Range and are receiving dynamic support from a shortwave trough moving northeastward across the Interior. More numerous showers are occurring across the Alaska Range and will persist through the next few days. Snow will be heaviest on the southern side of the Eastern Alaska Range south of Trims Camp; near the Richardson Highway, some surface melting during the daytime periods followed by later refreezing could result in slick road conditions.

The primary weather maker for the next few days will be an extratropical cyclone over the southern Bering Sea. The minimum central pressure of the low-pressure center of this system is estimated to be around 960 mb. While the surface low will be fairly strong (and vertically-stacked with its corresponding upper low), it will not directly affect land at this intensity; the primary impacts will instead occur along the leading warm front well east of the low, where brisk easterly to northeasterly winds will blow across the northern Bering Sea and adjacent coastal areas. In the Bering Strait and through the Chukchi Sea, they will have a more northerly orientation. The front will move ashore over the YK Delta by this afternoon/evening and with it, a broad line of precipitation will begin to affect the area while moving in a consistent southwest-to-northeast direction. Ridging over the eastern Aleutians ahead of this system will push eastward, with meridional flow setting up over southcentral Alaska. By this afternoon and evening, snow showers in the southern Alaska Range should dwindle. Tonight into tomorrow, ahead of the upcoming front, additional showers will develop in the Central/Eastern Interior and may be convectively driven, with many forming off the higher terrain. These showers will likely continue through Saturday evening, and their precipitation type could be diurnally- driven in the valleys, with rain more likely during the afternoon/evening hours. Heavy snow on the south side of the Alaska Range will likewise resume tonight, with upslope flow supporting high snowfall rates at times. There could still be some messiness, with potential icy/slick conditions again possible.

The front itself will largely affect the Western and Central Interior from Sunday through Tuesday. In these areas, liquid- equivalent precipitation could range significantly, with lower totals around 0.2 inches on the margins to higher totals of ~0.7 inches near the center of the main band. In spite of some briefly warmer temperatures with the initial warm front, temperatures even in valleys locations in the Western Interior will remain fairly cool, with most precipitation falling as snow. The best chances for any daytime rain mixing in with snow will be in the Lower Upper Kuskokwim and Lower Yukon Valleys. Snow ratios could be high; models soundings indicate potential for saturated dendritic growth zones which could support ratios of 15:1 or higher at times. This will allow for many areas to potentially receive 6 inches or more of snow through Tuesday morning, especially between the Lower Yukon Valley and Bettles. The Dalton Highway Summits, White Mountains, and Yukon Uplands could also potentially see several inches of snow accumulation. There is uncertainty on snow totals for the Middle and Upper Tanana Valleys, but ensemble guidance supports the potential for at least a few tenths of an inch of liquid equivalent precipitation with numerous showers in the area, especially Sunday night into Monday morning. If this were to verify, multiple inches of snow would be possible in the area (although this could be affected by melting during afternoon periods).

While snow totals across much of the West Coast/St. Lawrence Island will likely be lower than inland, blowing snow will be possible where fresh or especially falling snow can combine with strong winds. Blizzard conditions are possible over both the YK Delta and St. Lawrence Island, but potential will depend on how much snowfall either area can get (and how winds coincide with falling snow). On Sunday, while there will generally be zonal flow aloft over the Alaska Range, which is not usually supportive of gap winds, there will be a strong surface pressure gradient of about 6 to 8 mb across the mountains. This will permit breezy/gusty winds through the passes. Easterly winds will also pick up on the eastern Arctic Coast from Sunday into Monday night as high pressure develops over the Beaufort Sea.

EXTENDED FORECAST DAYS 4-7

Tuesday in Wednesday, cold air with the Arctic trough will again dip into Western Alaska, dropping highs below freezing. It will then wrap eastward behind the last remaining snow showers in the Interior from the previous system and cause high temperatures on Tuesday to fall into the mid or low 30s even in the warmer valley areas. This will be short-lived, as another system entering the eastern Bering Sea pushes a warm front across the area which will push the cold air back out. Along the front, as with the previous system, winds will generally be easterly and strongest over the water. It will also bring another round of precipitation, with better chances for rain or rain/snow mix in the Western Interior than with the first system given the warmer airmass. The precipitation band moves in a more south-to-north direction, which will also limit the precipitation in the Central/Eastern Interior to a greater extent while allowing for much more to fall over the western North Slope. By the late week period, highs in parts of the Interior could rise into the 50s, with highs on the West Coast rising back above freezing and highs on the North Slope rising into the teens above.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Wind Advisory for AKZ849. Winter Weather Advisory for AKZ850. Winter Storm Watch for AKZ850. Winter Storm Watch for AKZ824. Winter Storm Warning for AKZ825. Winter Storm Watch for AKZ827. Winter Storm Watch for AKZ829. Winter Storm Watch for AKZ832. PK...Brisk Wind Advisory for PKZ801. Gale Warning for PKZ802. Brisk Wind Advisory for PKZ803-852. Brisk Wind Advisory for PKZ804-805. Brisk Wind Advisory for PKZ806-807-810-811-856-857. Heavy Freezing Spray Warning for PKZ816. Gale Warning for PKZ816-817. Gale Warning for PKZ850. Storm Warning for PKZ851. Gale Warning for PKZ853. Storm Warning for PKZ854.