textproduct: Fairbanks

SYNOPSIS

A fairly active pattern is expected over the weekend for much of the state. A low is slowly moving north over St. Lawrence Island bringing a mix of rain and snow up the West Coast as it progresses. A series of shortwaves will be moving up and over a strengthening ridge in the eastern portion of the state. This may result in warning level wind gusts through the Alaska Range during the day on Friday. The south/southwest flow will persist over the West Coast for much of the period, allowing for continuous precipitation and gusty winds through the end of the weekend. Around normal temperatures are expected across the state. However, the positioning of the low in the NW Arctic may allow for some cooler minimum temperatures for portions of the West Coast and North Slope by the end of the weekend.

KEY WEATHER MESSAGES

Central and Eastern Interior... - Southerly wind speeds are expected to increase through the Alaska Range passes late tonight as a High Wind Warning goes into effect. Wind gusts through the passes are expected to be around 70 to 75 mph. The strongest winds will occur between Friday morning and Friday evening. - A Wind Advisory is also in effect for Delta Junction at the same time, with expected gusts around 55 mph.

- Southerly flow over the Alaska Range and drier conditions will continue to support near normal to above normal temperatures this week, with highs in the 40s/50s and lows in the 20s/30s.

- The next chance for scattered rain showers across the Interior will begin early Saturday morning and lasting throughout the day with the shortwave passage.

West Coast and Western Interior... - Precipitation is expected to persist across much of the West Coast over the next several days. - Precipitation is expected to be mostly snow at higher elevations and in the overnight hours and mostly rain at lower elevations and during the day. Snow accumulations are more likely for higher elevations.

- Gusty winds will continue through much of the weekend with speeds between 25 and 35 mph. The higher wind speeds will be toward the northern portions of the West Coast.

- Temperatures will range from highs in the 30s/40s along the coast to 40s/50s farther inland with lows around 30.

North Slope and Brooks Range.. - A front associated with the first low will continue to bring light additional snowfall accumulations expected in this region. Winds will increase in the Brooks Range this morning with gusts up to around 30 mph.

- Another low will bring rain/snow showers to the Western Brooks Range and North Slope by this evening, spreading eastward by early Saturday morning. Winds will increase as the precipitation begins with gusts up to around 35-45 mph for the Arctic Coast and higher elevations of the Brooks Range. Patchy areas of blowing snow could reduce visibility at times.

- Temperatures will gradually warm throughout the rest of this week, ranging from highs in the 30s/40s for the Brooks Range and Western Arctic Coast to 20s/30s for the Arctic Coast and Plains. Lows will mostly be in the teens/20s to low 30s farther south.

FORECAST ANALYSIS AND DISCUSSION

Not much change to the overall forecast as persistence continues to hold strong. A broad trough stretches across the Bering from the Chukchi to south of the Aleutians. Meanwhile, a subtle ridge is set up over the Al-Can border and will continue to push N/NE through the end of the week. This sets up broad south to southwesterly flow across most of the state, suitable for wet conditions over the West Coast and windy conditions through the Alaska Range.

As of this afternoon, an upper-level low sits over St. Lawrence Island and expected to continue moving north, just past the Bering Strait before stalling out by Friday afternoon. A shortwave will move over the Alaska Range Friday afternoon, setting up the potential for gusts as high as 75 mph through the Alaska Range passes. With the S/SW orientation of the upper-level flow and the tight gradient portrayed by numerous models, confidence for warning level winds are higher for Isabel Pass than Windy Pass. As the shortwave reaches the Brooks Range around Saturday, it will become shredded as the some of the energy continues to ride over the ridge axis and some gets wrapped into the low just north of the Bering Strait. With the positioning of this low, a cooler airmass will move over the western portion of the state, by Saturday, as a weak cold front wraps around the low and moves over the West Coast. The energy associated with this front will continue to support the wet conditions across most of the West Coast, eventually expanding across the south slopes of the Brooks Range. This will eventually spread across portions of the Interior as the southerly flow turns more southwesterly. However, precipitation will be light as it will have to punch through a very dry layer at the surface, that was set up by the southerly flow.

As the front moves over the Brooks Range Saturday, portions of the Arctic Plains will remain dry due to downsloping. However, some of the moisture will reach the Arctic Coast bringing their next chance for mixed precipitation. With the southerly flow coming over the Brooks Range, the downsloping may produce a warm nose at the mid- levels. This brings a slight chance for freezing drizzle across the Arctic Coast as the front moves over Saturday afternoon/evening.

The low, previously stationary just north of the Bering Strait, will begin to slowly move N/NE as another ridge builds in from the western Bering by the end of the weekend. This may continue to support the cooler upper-level temperatures across the West Coast by the start of next week.

EXTENDED FORECAST DAYS 4-7

The pattern is expected to look fairly by the start of the extended portion of the forecast. All models are showing ridging continuing over the mush of the eastern Gulf of Alaska, with some of it stretching up the Al-Can border. Models also show the potential for another low to moving north from the Gulf and coming across the Alaska Range, similarly to the pattern that is seen in the short term. However, the EC shows a slightly different solution with the system being much weaker which will allow it to move farther east as it rides over the ridge axis. This solution would not be suitable for another round of gap winds through the Alaksa Range. If the gap winds were to occur, the current time frame for the strongest winds will be Monday night into Tuesday.

Looking back over the NW Arctic Coast, models are not in agreement when it comes to the track of the upper level low. The track of this low will also play a role into how well the southerly orientation sets up over the Alaska Range. Models are also showing the potential for another ridge to continue to strengthen over the western Bering. With a bunch of moving parts and various solutions being seen amongst models, this will continue to be watched over the next several couple of days.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...High Wind Warning for AKZ847-849. Wind Advisory for AKZ837. PK...Small Craft Advisory for PKZ804. Brisk Wind Advisory for PKZ805-852. Brisk Wind Advisory for PKZ807. Brisk Wind Advisory for PKZ808. Brisk Wind Advisory for PKZ809-855. Brisk Wind Advisory for PKZ811-812-857-858. Brisk Wind Advisory for PKZ813-814-859-860. Brisk Wind Advisory for PKZ815-861. Brisk Wind Advisory for PKZ856.