textproduct: Fairbanks

KEY MESSAGES

Central and Eastern Interior...

- An arctic cold front will push southeast through the central and eastern Interior overnight and into early Wednesday with some scattered mainly light rain showers.

- Colder Air will quickly fill in behind the front allowing for snow levels to drop to between 1000 and 1500 feet which could bring a dusting of early season snow to some of the higher terrain north and east of Fairbanks.

- Along with colder temperatures, gusty west winds will likely follow the front through the Tanana Valley Wednesday, potentially gusting as high as 20 to 30 mph in spots.

- Wednesday's highs will be in the 40's and 50's followed by the first hard freeze of the season for Fairbanks and other Interior spots with lows falling into the 20's to about 30 as skies clear and winds diminish Wednesday night into Thursday morning.

- A warm front will push north over the Alaska Range and into the Interior late week and into the weekend with strong southerly winds affecting the Alaska Range passes and additional rainfall Thursday through the upcoming weekend.

West Coast and Western Interior...

- A storm in the Bering will begin to bring a warm front across the Yukon Delta with increasing chances for rain Wednesday. Increasing moisture with this system will allow for widespread rainfall across the rest of the west coast Wednesday night through Friday.

- The western Interior will also see significant rainfall Thursday and Friday as the Bering system taps into an atmospheric river allowing for ample moisture transport into western Alaska.

- Total rainfall for western Alaska through the end of the week will range from .05" to 1.50" with the potential for upwards of 2" in spots, especially the southern Seward Peninsula and across St Lawrence Island.

- Strong SE winds are likely Thursday throughout the Norton Sound with winds shifting to the S/SW Thursday night into Friday across the west coast. Winds gusting 20 to 40 mph will be common across western Alaska through Friday with gusts potentially ranging from 30 to 50 mph for St Lawrence Island.

- Heavy surf conditions will be likely Thursday into Friday with water levels reaching 1 to 3 feet above the normal high tide level.

North Slope and Brooks Range...

- Snowfall will be the primary concern for the North Slope and Brooks Range through Wednesday as a series of Arctic fronts move through the area.

- Strong onshore flow from the Chukchi across the Northwest Arctic coastline will continue to produce convective bands of snow or rain/snow through Wednesday evening. Some of the individual precipitation bands could be heavy at times.

- Across the central and Eastern Brooks Range and adjacent North Slope area, steady upslope snowfall will allow for another round of significant snowfall through early Thursday. Additional snow totals of 3 to 6 inches will be common at elevations above 2000 feet with lower elevations seeing between 1 and 3 inches of new snowfall.

- Another round of steady snowfall is likely across the western Brooks Range Thursday into Friday as a storm in the Bering sends more moisture north into the region.

SYNOPSIS

Winter is in the process of making an appearance across northern Alaska as an Arctic cold front brings snowfall to much of the North Slope and Brooks Range while potentially setting up the first hard freeze of the season for portions of the Interior through Thursday morning. Meanwhile a system in the Bering will begin to take over for the rest of the week and weekend. This system will bring high surf to the West Coast along with periods of moderate to heavy rain Wednesday into the weekend. This system will also bring back southerly flow that will allow for increased winds through the Alaska Range passes late in the week and allow for increasing temperatures for the Interior.

SHORT TERM /THROUGH FRIDAY NIGHT/

An elongated Arctic trough remains in place across all but southwest Alaska as of Tuesday afternoon allowing for generally cooler and somewhat unsettled conditions. This trough is anchored by a fairly robust closed upper low located across the southcentral Beaufort Sea. This feature is forcing a strong Arctic cold front southwards across the Brooks range and towards the Interior as upper shortwave energy rotates around this upper low. These features combined will likely produce steady and somewhat significant snowfall for the central and eastern Brooks Range and adjacent portions of the North Slope this evening through Wednesday. Heaviest snowfall will likely occur along a line stretching from Anaktuvuk Pass to Atigun Pass and then up towards the eastern Arctic coastline near Kaktovik. Elevations above 2000 feet could see between 3 and 6 inches of additional snowfall with 1 to 3 inch snowfall totals below that elevation. Closer to the coast snowfall totals may be a bit trickier as some of the precipitation may initially fall as a rain or a rain/snow mix before it gets cold enough to become strictly snowfall. However 2 to 3 inches is still possible in these regions as well. Further to the west, strong west flow behind this front continues to produce "ocean effect" type bands of snow and rain showers. Some of these showers will be heavy at times and this activity will likely continue into later Wednesday before the wind speed drops off a bit.

Meanwhile as the cold front makes it's way south and east through the Interior, additional bands of mainly rain showers will develop along the from itself this evening and overnight with the precipitation shifting to near the Canadian border by midday Wednesday. Brisk west and northwest winds behind the front will bring noticeably colder conditions to the interior and will lower snow levels to between 1000 and 1500 feet overnight tonight and early Wednesday. There is the potential for a dusting to a few inches of snow for the higher terrain of the White Mountains, but lower elevations should only see lighter rain. But with clearing skies by Wednesday night, low temperatures are expected to drop to below freezing for a large portion of the interior, including Fairbanks where the first actual "hard freeze" of the season will be possible. But this early taste of Interior winter will be short-lived as a storm system in the Bering will begin to push warmer and more moist conditions into the Interior later Thursday and into the weekend.

Speaking of the Bering system, a closed upper low currently in the vicinity of the western Aleutians will be slowly shifting to a position in the northern Bering over the next several days. Southerly flow around this system will initially push a warm front across the Yukon Delta Wednesday afternoon signaling the beginning of a significant rainfall event for western Alaska in the days ahead. This frontal band of precipitation will expand northwards into the Norton Sound and Seward Peninsula as well as portions of the western and central Interior Thursday and Friday. In addition GFS and ECMWF IVT products indicate a significant Atmospheric River setting up behind the warm front which will further enhance rainfall across the West Coast into Friday. While the general consensus is for anywhere from .50" to 1.50" of rainfall in the days ahead, there will be locations under the AR that could easily see upwards of 2" inches of rainfall including the southern Seward Peninsula as well as St Lawrence Island.

Another aspect of this Bering system will be the enhanced wind field around the parent circulation. With the low over the Bering and a north Pacific ridge nosing into eastern Alaska, the gradient will support enhanced southerly flow. Over the Norton Sound gusty SE winds will be the norm Thursday with more a southerly fetch over the eastern Bering Sea. As the flow shifts to the S/SW Thursday Evening and into early Friday, increased water levels are expected along the west coast. High surf will be likely with guidance suggesting a general water level rise of 1 to 3 feet for most west coast locations by Thursday night and early Friday.

LONG TERM /SATURDAY THROUGH TUESDAY/

Saturday through Sunday a Bering Sea low will begin to track east towards Alaska, weakening the north Pacific ridge, and forcing it east out of our area. During this time, the associated warm front will extend from the West Coast of Alaska into the Interior, bringing wetter weather, with a gradual warming in temperatures following this front. This low will remain relatively stationary within the Bering Sea until a new low approaches Sunday evening.

As the extended comes to an end, another low pressure system originating from the roughly 40N, will track northeast towards Alaska Sunday evening. There is potential for this low to form a triple point with the preceding bering sea low, which could have significant implications for this systems strength, such as the strength of wind gusts, or amount of precipitation.

The impacts of this system will greatly depend on the path the low takes. As the low pressure system approaches Alaska into Monday, the path of this system remains uncertain. If the storm tracks north through the Bering Sea and enter Alaska through the YK-Delta there will be higher chances for more substantial rainfall early next week. However, if the system trends toward the Gulf, and approaches Alsaka from the south, the moisture associated with this storm will be focused outside of our area. This system will need to be remained monitored until the models demonstrate better agreement on its strength and impact on Alaska.

Coastal Hazard Potential... While the Bering Sea storm will provide a focus for heavy rain and surf, minimal coastal concerns are expected. Initially, the strongest winds Thursday look to remain from the S/SE and favor more offshore flow. Winds shifting to the S/SW late Thursday into Friday however, could lead to higher storm surge around the Yukon Delta and Norton Sound region. High surf is possible in this area, with water levels potentially reaching 1 to 3 feet above the normal high tide.

FIRE WEATHER

The low from the northern Gulf of Alaska continues to push farther S/SE along the Alaska Peninsula. This has provided the Upper Tanana with another day of broken to overcast clouds and isolated rain showers. Majority of the rainfall has remain SE of Tok with totals between 0.05" and 0.2" of additional QPF over the last 12 hours. A NW-SE moving cold front will begin dropping another round of showers across the Upper Tanana beginning early Wednesday morning. A cold, Arctic airmass will accompany this system which may allow for some higher elevations to see a rain/snow mix. Regarding QPF values, an additional 0.05" to 0.15" can be expected across the Upper Tanana Valley through Wednesday night. With the passing cold front, this will allow for a gradual cooling trend over the next day or so, with the coldest timeframe expected Wednesday night into Thursday morning. In addition, the passing front will bring another round of gusty, W/NW winds Wednesday afternoon with potential gusts up to 30 mph. A strong ridge will begin to build in behind this ridge from the Gulf of Alaska. This ridging will result in a weak chinooking pattern across the eastern Alaska Range. This will allow for warmer temperatures and drier conditions to return across the Upper Tanana with highs around 70 degrees and minimum RHs between 40 and 50 percent by the start of the weekend.

HYDROLOGY

Overall rainfall amounts Wednesday through Friday night continue to indicate around 0.5 to 1.5 inches across the Central/Western Interior, Brooks Range, and Western Alaska. Locally higher totals up to around 2 inches will be possible across the West Coast. Expect water level rises on area rivers and streams as a result of this rainfall, but no flooding is anticipated at this time.

AFG WATCHES/WARNINGS/ADVISORIES

AK...None. MARINE...Small Craft Advisory from 1 PM to 6 PM AKDT Wednesday for PKZ801-816-850. Small Craft Advisory from 4 AM to 7 AM AKDT Wednesday for PKZ811-812-857. Small Craft Advisory from 4 PM to 6 PM AKDT Wednesday for PKZ817. Small Craft Advisory from 1 AM to 6 PM AKDT Wednesday for PKZ851.