textproduct: Fairbanks

SYNOPSIS

As a low pressure system works east through Southcentral Alaska today into Wednesday, snow showers will persist across the Interior, shifting west to east before becoming increasingly isolated Wednesday night into Thursday. Additional snow amounts of 1-4" are expected across the Interior south of Bettles, with locally higher amounts up to 8" in the Alaska Range. On the backside of this system, wind gusts up to 50 mph will continue from the NW Arctic Coast and Western Brooks Range through the Bering Straight to St. Lawrence Island today, with winds subsiding tonight into Wednesday. Looking north, very cold wind chills as low as 70 below zero look to also continue across the Eastern North Slope today into tonight. As clearer skies make a return mid to late week upon the exit of this system, temperatures will trend colder across Northern Alaska heading into the weekend. A frontal boundary remains on track to lift north from the Gulf of Alaska this weekend, bringing an increase in clouds, snow chances, warmer temperatures, and gusty winds along the West Coast and across higher elevations.

KEY WEATHER MESSAGES

Central and Eastern Interior...

- Snow chances will continue to shift east across the Interior through Wednesday, tapering off Wednesday night into Thursday. Total snow accumulations of 1-4" are expected with locally higher amounts up to 8" in the Alaska Range.

- Elevated E/NE winds will persist today into tonight across higher elevations and the Middle Tanana Valley, shifting south to the Alaska Range and Upper Tanana Valley for Wednesday.

- Warmer temperatures have returned to the Interior, with colder conditions expected to build back in Wednesday into Thursday as snow ends west to east and skies become increasingly clear. Widespread 30s/40s below zero will return as a result. Coldest areas will get down to around 50 below zero.

- Another round of snow and slightly warmer temperatures are expected to build back into the Interior Friday through the weekend as a front lifts north from the Gulf of Alaska.

West Coast and Western Interior...

- Wind gusts up to 50 mph will continue today from the NW Arctic Coast through the Bering Straight to St. Lawrence Island, leading to areas of low visibility ahead of winds subsiding tonight. Isolated snow showers will persist today along the West Coast.

- Light snow will continue to shift east across the Western Interior today, with an additional 1-2" expected especially closer to the Central Interior. Dry conditions will return for Wednesday and Thursday, as snow showers continue for St. Lawrence Island.

- Following a brief warmup, colder conditions will build back in tonight into Wednesday, as snow ends west to east and skies become increasingly clear. Widespread 20s/30s below zero will return as a result, with even colder wind chills at times. Coldest areas will get down to around 40 below zero.

- Another round of snow and slightly warmer temperatures are expected to build back into the Interior Friday through the weekend as a front lifts north from the Gulf of Alaska. Gusty winds are also favored to develop along the West Coast during this timeframe.

North Slope and Brooks Range...

- Very cold and dry conditions will remain in place over the North Slope. Widespread temperatures in the 20s/30s below zero will persist, with 40s/50s below zero in the coldest spots.

- Wind chills as low as 70 below zero will continue for the Eastern North Slope, where a Cold Weather Advisory remains in effect through tonight.

- Northeasterly winds gusting up to 50 mph continue across the NW Arctic Coast and Western Brooks Range through tonight, resulting in blowing snow reducing visibility to near or below 1/2 miles at time.

- Snow showers look to return by the weekend up north, as moisture from the Gulf of Alaska lifts north over the Interior towards the North Slope.

FORECAST ANALYSIS AND DISCUSSION

Today through Thursday Night. Early morning satellite imagery shows a 965 mb surface low working east through Southcentral Alaska, with a 500 mb low around 486 dm centered over the Western Interior. This setup will continue to allow for snow to shift east across the Interior, as isolated snow showers and gusty winds persist along the West Coast. Winter Weather Advisories remain in effect from the NW Arctic Coast through the Bering Straight to St. Lawrence Island today, with wind gusts up to 50 mph leading to visibility down to around 1/2 mile at times, ahead of winds subsiding later today into tonight. The timing of these advisories will continue to be monitored as winds taper off later today. Across the Interior, snow showers will progress east as that low in Southcentral shifts southeast towards the Gulf of Alaska. This track will ultimately cutoff moisture transport further north Wednesday night into Thursday, but until then, we are looking at an additional 1-4" of snow through then with up to 8" in the Alaska Range.

Outside the Alaska Range, we could see locally higher totals across the Central Interior dependent on snow ratios and where some of the heavier snow bands set up. Should this event overachieve our current forecast in this corridor as some CAMS are pointing towards the potential of this morning, we could see totals closer to 4-8" which we will continue to monitor. This solution will also depend on moisture transport over the Alaska Range, with some newer model runs showing the potential for more efficient wrap around bands of snow to fill in across the Interior later today into Wednesday. Atmospheric profiles are considerably colder than our December snowfalls and only a fraction of the DGZ is included early in the event. By this afternoon, the profile is expected to be colder than the DGZ, suggesting SLRs should drop to around 10:1, but if the event average stays around climatology of around 16:1, we could see forecast totals overachieve in this corridor. The latest NBM 5.0 shows these ratios staying around 16:1 throughout the event, which we will continue to evaluate throughout for any changes to the forecast.

Following widespread cloud cover and an increase in winds that brought warmer temperatures to much of the Interior over the past 24- 48 hours, clearer skies and lighter winds building in out of the west will support the return of colder conditions as snow tapers off. Widespread 30s/40s below zero are expected to return later this week, with coldest areas dropping back to around 50 below zero. Up on the North Slope and in the Brooks Range, a persistent very cold and dry pattern continues to prevail, with a Cold Weather Advisory remaining in effect for the Eastern North Slope. Wind chills as low as 70 below zero will continue through midweek for this corridor with widespread air temperatures in the 20s/30s/40s below zero.

EXTENDED FORECAST DAYS 4-7

Friday through next Tuesday. Increasing confidence continues to support a series of strong low pressure systems moving into the NE Pacific and Gulf of Alaska to finish out this week into early next week. The first system, a surface low around 950-960 mb, will lift northeast into the Gulf of Alaska for Friday, with a front extending north towards Northern Alaska. This setup would support wrap around moisture as S/SW flow begins to prevail aloft, bringing about the return of widespread snow chances building in out of the SE to NW for Friday into Saturday across the Interior. Winds will also steadily increase along the West Coast and across higher elevations during this timeframe. As this first system weakens and moves inland, another low looks to fill in behind following a similar track, helping to keep snow chances around into early next week. One close aspect of these systems that we will be watching for through next week is if will we end up seeing an Alaska Range chinook event, which could bring stronger winds and warmer, drier air into the Interior. Even without that, temperatures are expected to trend warmer overall given increased cloud cover and snow chances through the extended forecast, still remaining broadly below normal.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Winter Weather Advisory for AKZ801-815-820-821-827. Cold Weather Advisory for AKZ804-805-808>810. PK...Brisk Wind Advisory for PKZ801-802-805-810-850-852. Brisk Wind Advisory for PKZ804. Gale Warning for PKZ806-807-817-854-856. Brisk Wind Advisory for PKZ808. Brisk Wind Advisory for PKZ811-857. Gale Warning for PKZ816. Heavy Freezing Spray Warning for PKZ816-817-851-854. Gale Warning for PKZ853. Brisk Wind Advisory for PKZ855. Brisk Wind Advisory for PKZ858.