textproduct: Fairbanks

SYNOPSIS

Relatively stable weather expected for the first part of the week with northerly flow and unseasonably cold Interior temperatures expected. More moderate, but still cool temperatures expected along the coast with occasional periods of gusty winds, northerly for the West Coast and westerly for the Arctic Coast. Periods of blowing snow possible through Alaska Range passes as northerly winds increase Sunday due to a building low in the Gulf of Alaska. This same low brings some light snow to the southeastern Interior Sunday and Monday. The colder weather for the region is very likely to last through the end of the week.

KEY WEATHER MESSAGES

Central and Eastern Interior...

- Well below normal to near record cold temperatures for this time of year continue this upcoming week. More moderate temperatures Sunday morning cool with lows once again in the 30s and 40s this week.

- North winds increase through the Alaska Range passes Sunday through mid next week. A Winter Storm Watch for near blizzard conditions has been issued for the Alaska range passes.

- Mainly dry for the majority of the Interior, with the exception of the Upper Tanana Valley and far eastern Interior where snow is possible Sunday through Monday. Gusty northwesterly winds through the Upper Tanana Valley Sunday night through Monday may lead to periods of blowing and drifting snow.

West Coast and Western Interior...

- Northerly winds along the West Coast weaken Sunday morning.

- Relatively milder conditions continue through this weekend, but below normal temperatures return next week with double digit subzero lows.

- Another period of gusty northerly winds and light snow possible for the Bering Strait and West Coast mid to late week.

North Slope and Brooks Range...

- Light to moderate westerly winds across the Arctic Coast through the week. 10 to 20 mph generally, strongest along the eastern Arctic Coast occasionally gusting up to 30 mph. Periods of reduced visibility due to blowing snow possible.

- Light snow and periods of blowing snow likely Sunday along the northern slopes of the Brooks Range. Accumulations generally between trace and 0.5 inches.

- Temperatures cool slightly and remain mostly steady through the week with highs in the single digits and teens below 0 and lows in the 20s to teens below 0.

FORECAST ANALYSIS AND DISCUSSION

For Sunday through Tuesday night. At the start of the forecast period, the overall pattern is dominated by a strong 570 decameter upper level high at the top of a ridge pattern in the Western Bering Sea. This feature effectively blocks weather from the west eliminating the most common moisture source for Northern Alaska and promoting flow from the north. This results in a relatively dry and cold pattern for Northern Alaska which will likely last as long as that ridge remains in place.

A strong 481 decameter upper level low north of the Hudson Bay, far to the east in Canada, provides the greatest variation in weather over the next several days by slinging shortwave lows into the region from the north. As these shortwaves are coming from the far north over the frozen Arctic Ocean they are relatively dry but will provide some light snowfall to the North Slope and parts of the West Coast as they move south. They also increase the pressure gradient along the West Coast increasing wind speeds when the stronger shortwaves move through the pattern.

On Sunday one of these stronger shortwaves continues south into the Gulf of Alaska allowing the pressure gradient along the West Coast to weaken which lowers their winds, but increases northerly winds through Alaska Range passes as it moves into the Gulf of Alaska. Once in the Gulf of Alaska this shortwave becomes able to better sustain itself and forms into a more distinct and independent low pressure system. This 'new' low in the Gulf of Alaska complicates the otherwise simple pattern slightly by increasing cloud cover over Interior Alaska and pushing some light snow around the mountains and into the Southeastern Interior Sunday into Monday. Higher pressure builds into the Interior in the wake of the shortwave as cold air is pulled from the north to settle over the Interior. Cloud cover will slightly mitigate the coldest valley temperatures by limiting nighttime cooling, but gaps in cloud cover will allow for notable and unseasonably cold low temperatures across the Interior as strong inversions develop. Unseasonably cold temperatures are expected across the region through the much of the week as this colder, denser air settles into the region.

EXTENDED FORECAST DAYS 4-7

For Wednesday through next Sunday. At the start of the extended forecast period Wednesday, another strong shortwave moves through the region from the north bringing another round of gusty northerly winds along the West Coast and through mountain passes as well as some additional light snow along the West Coast. This reinforces the previously weakening low in the Gulf of Alaska and weakens the Bering Sea ridge making a pattern change slightly more likely for the next week. Otherwise conditions remain relatively dry and cold through the end of the week.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Winter Storm Watch for AKZ848-850. PK...Brisk Wind Advisory for PKZ806-807-816-817-850-851-856. Brisk Wind Advisory for PKZ853-854.