textproduct: Fairbanks

SYNOPSIS

Well below normal temperatures for early March continue for the majority of Alaska through the rest of the week. The increasing sun angle is allowing for a brief reprieve from the brunt of the cold as afternoon highs are now rising to near zero. The only active weather in the region today is confined to the Northeast Arctic Coast where snow and blowing snow are leading to reduced visibility. Relatively benign weather expected tomorrow as conditions improve along the Arctic Coast; however there will be a chance of snow in the upper Tanana Valley and along the Alaska/Canadian border with only minor accumulations possible. Focus shifts to late week as a more pronounced system moves up the Aleutians and into South Central Alaska bringing a round of accumulating snow to the Alaska range and possibly portions of the Interior into the weekend. At the same time, northerly winds ramp up through the Bering Strait Thursday into the weekend which may result in blowing snow and reduced visibility for portions of the West Coast and St. Lawrence Island. Into the extended, much colder than normal weather persists as reinforcing shots of arctic air settle into the state from Siberia.

KEY WEATHER MESSAGES

Central and Eastern Interior...

- Daytime highs moderate into the single digits below and above zero due to the increasing sun angles and sufficient daytime heating

- A brief round of light snow expected for the Upper Tanana Valley and forty mile country on Wednesday, minor accumulations possible

- Another chance for accumulating snowfall for most of the southeast Interior and Alaska Range late week into the weekend. Winter Storm Watch for heavy snow has been issued for the Eastern Alaska Range south of Trims Camp late Thursday night through Saturday.

West Coast and Western Interior...

- Anomalous cold continues across the West Coast with lows in the -20s and -30s along the coast and the -30s and -40s across the Western Interior.

- Northerly winds through the Bering Strait are expected to remain somewhat strong with sustained winds between 20-25 mph, gusting to 40-45 mph at times through Tuesday. Minor blowing snow conditions may develop due to plenty of fresh snow on the ground across the Seward Peninsula.

- Another round of strong northerly winds through the Bering Strait are expected later this week and into the weekend. Blowing snow concerns for coastal communities from Point Hope to the western Seward Peninsula and St Lawrence Island.

North Slope and Brooks Range...

- Winter Weather Advisory remains in effect through Wednesday morning for the Northeast Arctic Coast for reduced visibility from falling and blowing snow

- While temperatures across the central and eastern North Slope will remain fairly steady the next few days, noticeably colder conditions will be setting in across western parts of the North Slope.

FORECAST ANALYSIS AND DISCUSSION

The extended stretch of well below normal temperatures persists through the first week of March for the majority of Northern Alaska. Upper troughing remains in place over the YK Delta while surface high pressure extends from Siberia into Alaska keeping the very cold airmass in place. Lows once again this morning fell into the -25F to -45F range, with the coldest locations being interior valleys. The increasing sun angle will result in significant diurnal ranges on any clear day this time of year with afternoon highs now reaching zero and the single digits above in this pattern. Expect similar conditions through the rest of the week featuring large temperature swings between morning lows and afternoon highs for the majority of the Interior and West Coast.

Across the North Slope and Arctic Coast, low to mid level stratus and isolated snow showers have kept temperatures steadier in the teens below zero to near zero. An upper low remains in place over the Canadian Archipelago with numerous shortwaves rotating about it and into the arctic coast. PABR upper air soundings indicate a strong subsidence inversion at 750mb trapping moisture in the lowest 7,000ft agl. Shortwaves rotating around the upper low are helping advect moisture from the unfrozen Atlantic over the Poles and into Alaska, keeping the threat for clouds and scattered snow showers around. Expect this similar pattern to continue for the next several day; however winds along the NE Arctic Coast should slowly diminish Wednesday and Thursday as the gradient weakens some.

Watching for the chance of light snow on Wednesday for the Upper Tanana Valley and Forty Mile Country as a shortwave rotates around the upper low in the YK Delta, moving into the Gulf then northward along the Alaska/Canada border. There is enough moisture advected over the Wrangell St. Elias and into the SE Interior to support snow showers as this wave moves in. Model soundings show a very cold profile, mostly colder than the Dendritic Growth Zone, so expect smaller snowflakes and snow grains leading to only minor snowfall accumulations. Best chances for snow exist from Tok to Northway to Eagle and points east. Low confidence exists if upper clouds from this reach Fairbanks as the main forcing for ascent and moisture advection will all be to the east. In the case Fairbanks does see cloud cover, afternoon temperatures may be warmer than what is in the forecast.

EXTENDED FORECAST DAYS 4-7

Focus shifts to the next strong storm system to impact portions of the Interior and Alaska Range Friday through the weekend. A developing low moves northeast on the north side of a strong north pacific ridge, tracking up the AK Peninsula, then becoming quasi- stationary over South Central Alaska this weekend. While there is still low confidence on all of the finer details and evolution of this next system, confidence is increasing for heavy snow accumulations on the south side of the Alaska range with lighter snowfall accumulations in the Central and Eastern Interior Friday through at least Saturday. Winter Storm Watches have been posted for Isabell Pass and the Eastern Alaska Range and more winter weather headlines may be needed for surrounding areas as confidence increases.

Watching the track of this system closely as a slight shift east or west of the Alaska Range can significantly affect moisture advection northward into the Interior. Confidence is increasing in minor snow accumulations in the Central and Eastern Interior with brief periods of moderate to heavy snow at times Friday and Saturday, including the Fairbanks area. With the track of the mid level low potentially directly overhead, will have to watch if and where a deformation band sets up on the NW side of the surface low. A general rule of thumb is that the deformation band can develop directly under or in the vicinity of the 850mb low. If this occurs on the north side of the Alaska Range, there could be heavier snow accumulations in the interior. Confidence on the exact track is still low, so will keep any accumulations lighter for now and will update the forecast accordingly over the next several days.

For much of the West and North Slope, expect cold and fairly dry conditions to continue as northerly winds on the north side of the aforementioned system keep the arctic airmass in place.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Winter Storm Watch for AKZ850. Winter Weather Advisory for AKZ805. PK...Brisk Wind Advisory for PKZ803. Brisk Wind Advisory for PKZ804. Brisk Wind Advisory for PKZ805. Brisk Wind Advisory for PKZ806-807-811. Brisk Wind Advisory for PKZ810. Brisk Wind Advisory for PKZ815-861. Brisk Wind Advisory for PKZ816-817-851-854. Brisk Wind Advisory for PKZ852. Brisk Wind Advisory for PKZ856. Brisk Wind Advisory for PKZ857.