textproduct: Fairbanks

SYNOPSIS

A disturbance in the northern Gulf of Alaska has allowed for an abundance of rain/snow to fall across the Interior over the past 12 to 15 hours. The heaviest periods have passed, however some showers may continue to linger through portions of the day. As the low begins to push SE, this will briefly increase the gradient across the Alaska Range allowing for northerly winds to gust between 30 and 40 mph. This may result in periods of blowing snow through the passes. Over the West Coast, the stronger winds over the Bering Strait should lighten throughout the day with a much quieter weather day compared to previous days. This will be short- lived as another system will begin to make its way over the YK- Delta Tuesday afternoon, bringing another round of diurnally driven precipitation. The front will eventually stall around the central portion of the state as another upper-level low moves south from the Arctic. This will also set up a seasonably colder airmass across the Arctic Plains which will allow for lows in minus teens by Wednesday morning. Active weather is expected to continue through most of the week as the upper- levels return to a west/southwesterly orientation and a series of shortwaves move east from the Bering Sea.

KEY WEATHER MESSAGES

Central and Eastern Interior... - Rain/Snow mix is expected to continue across the Eastern Alaska Range and Upper Tanana Valley throughout the day with lighter accumulations lingering into early Tuesday. Winter Storm Warnings and Winter Weather Advisories have been issued. Most of the heaviest snow has already fallen.

- Light snowfall is expected across the Fortymile Country and White Mountains through the rest of the day. North to northeasterly wind gusts of 20 to 30 mph could lead to areas of blowing snow. Conditions are expected to improve by Tuesday. - Northerly winds gust up to 40 mph through the Alaska Range Passes today. Northwesterly wind gusts up to 30 mph are possible through the Upper Tanana Valley. There may be areas of reduced visibility when paired with falling snow. Near whiteout conditions are locally possible where the strongest gusts and heaviest snow overlap.

West Coast and Western Interior... - Gusty north winds will remain elevated along the Bering Strait throughout the day, with gusts as high as 30 mph. Patches of fog and blowing snow may persist through the end of the day as well.

- Temperatures cool throughout the week with highs in the 20s and overnight lows in the teens to single digits above zero. Slick and icy surfaces may form where liquid or melting precipitation freezes overnight.

- Another round of precipitation approaches the West Coast Tuesday bringing periods of light rain, snow, and mixed precipitation to portions of the West Coast and Western Interior Tuesday through the end of the week. Precipitation will be most consistent for areas south of the Bering Strait along the West Coast and south of Huslia across the Western Interior.

North Slope and Brooks Range.. - Scattered snow showers linger across the Brooks Range into next week, especially along southern facing slopes. Travel through Anaktuvuk Pass or Atigun Pass may be slightly impacted by light snowfall and breezy northerly winds.

- Temperatures rapidly cool Today and Tuesday and then remain cool through the end of the week. Highs fall to the single digits above zero while overnight lows reach as cold as the teens below zero. - Periods of gusty winds return to the northwest Arctic Coast Tuesday through the end of the week. Gusts as high as 40 mph between Point Hope and Point Lay. This may result in additional chances for blowing snow.

FORECAST ANALYSIS AND DISCUSSION

Unsettled weather continues across a good portion of the Interior thanks to an upper level 520 decameter low that has planted itself in the northern the Gulf of Alaska. The placement of this low has allowed for sufficient moisture wrap around into the Interior, resulting in the widespread rain/snow showers. Looking farther west, the bulk of the previous front has moved on. However some low-lying clouds and patchy areas of fog continue across some portions of the coast. Similar conditions can also be seen across the North Slope.

The upper-level low in the northern gulf will continue to spin in place through parts of the morning before beginning to shift SE toward the Alaska Panhandle. A couple of features are working in tandem, resulting in this movement. First off, an Arctic low will be pushing south over the North Slope. Accompanying this system will be a colder/drier airmass that is looking to set up across the Arctic Plains. The other feature is a ridge building up over the Bering, ahead of a low spinning in the far western Bering. Extending from this low, behind the ridge, is a front which will begin to move across the SW portion of the state by Tuesday afternoon. This is expected to bring another period of gusty winds and mixed precipitation to the YK-Delta and the Interior. The strongest N/NE winds are expected around St. Lawrence Island, the Bering Strait, and the Lisburne Peninsula. This may result in additional chances for blowing snow, especially over the NW Arctic coast. The northern progression of this front will be largely dependent on how far south the Arctic low moves. Latest guidance is showing the front stalling once it reaches the central portion of the state. At this point, the system is expected to get stretched out zonally, setting up another round of upper level west/southwest flow across a good portion of the state. Most of the precipitation from this system will start off as snow, with the help of the cold air advection from the systems this past week. When the SW flow sets up, aloft, around Wednesday afternoon this will allow for chances of rain to return to valleys below 1500ft. The chances for rain will be short-lived as most of the precipitation will return to mostly snow during the overnight hours. Similarly to the previous systems, precipitation types for this front will be diurnally driven.

One other part of this pattern that will be monitored is an upper-level ridge and surface high that will be simultaneously building over the Gulf of Alaska. This next front moving across the state will be tapping into another substantial pocket of moisture from the tropics. If the ridge is able the build up enough strength quick enough, this will allow for a much better transport of moisture into the central portion of the state. With most of the activity in the southern half of the state, this will allow for a more benign pattern over the North Slope. However, the cold air brought in from the north will allow for minimum temperatures in the minus teens to return by Wednesday morning and likely persist through a good portion of the week.

EXTENDED FORECAST DAYS 4-7

This active pattern across the southern half of the state is expected to continue into the later parts of the week. Models are also continuing to show signs of a stronger low to move across the Aleutians and move over the YK-Delta. Similarly to what was mentioned in the short-term portion of the discussion, the strength of the ridge in the gulf/western Pacific will be one of the main drivers in determining how far north this system is able to push. Current guidance is showing the associated front to begin to move over the YK-Delta sometime Saturday afternoon. Models are also showing the potential for another low to work its way south from the Arctic which will continue to support the westerly flow across the state throughout the extended forecast. A bit of uncertainty remains in place regarding timing and how much moisture will be able to move across the state. This will continue to be monitored over the next several model runs.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Winter Storm Warning for AKZ836-849. Winter Weather Advisory for AKZ848-850. Winter Weather Advisory for AKZ837-847. Winter Weather Advisory for AKZ834. PK...Brisk Wind Advisory for PKZ806-807-854-856. Heavy Freezing Spray Warning for PKZ816. Brisk Wind Advisory for PKZ851.