textproduct: Fairbanks

SYNOPSIS

An active pattern continues across a good portion of the state. Southerly flow over the Alaska Range is expected to provide gusty winds through the passes through Saturday afternoon. A series of shortwaves will be moving north through the Interior and over the Brooks Range through the end of the weekend. This will continue to provide chances for precipitation across much of the Central and Western Interior through the end of the weekend. These shortwaves will also develop a low level jet across the state which may allow for gusty conditions across the Interior on Saturday, which will be dependent on where the rain showers occur. Another low over the Bering Strait continues to spin, providing isolated areas of rain/snow to portions of the northern West Coast. This low is expected to move north along the Arctic Coast, bringing a cooler air mass, down from Siberia, over the West Coast by the mid weekend.

KEY WEATHER MESSAGES

Central and Eastern Interior... - High Wind Warnings remain in effect through Saturday afternoon. Wind gusts through the Alaska Range passes are expected to be as high as 75 mph. The strongest winds will occur through the early evening hours, tonight. A Wind Advisory is also in effect for Delta Junction for the same time period, with expected gusts around 55 mph.

- Winds will increase across the Interior on Saturday. Elevations above 1500ft could see gusts peaking around 40 mph with gusts to around 30 mph at lower elevations. The strongest winds will be in the afternoon, around peak heating.

- The next chance for scattered rain showers across the Interior will begin late tonight/early Saturday morning. Areas around the Alaska Range are expected to remain drier.

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 in the Nulato Hills and the hills north of Nome.

- 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.. - Blizzard warning remains in effect for Point Lay through 7pm tonight.

- Another low will continue to bring rain/snow showers to the Western Brooks Range and North Slope, 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. Winds are expected to remain elevated through Saturday night.

- 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

A fairly active pattern remains in place as the last week in April comes to an end. Southerly flow continues to dominate over much of the state. Observations overnight showed gusts peaking around 73 mph through both Isabel Pass and Windy Pass. Meanwhile, fresh snowfall along the NW Arctic has allowed for late season blizzard conditions over Point Lay.

As the weekend begins, much of the state will continue to be under the influence of southerly to southwesterly flow aloft. This trough has been tapping into a prominent atmospheric river that stretches from the central portion of the state to the Northern Pacific Basin. The upper-level shortwave, currently moving over the Alaska Range, will continue to push north across the Yukon Flats to the eastern Brooks Range. As this shortwave progresses, chances for precipitation will occur beneath this area are an abundant amount of moisture is available from the atmospheric river. A slight warm nose bay set up from the down sloping across portions of the Arctic Plains. This may allow for a chance for freezing drizzle during the day on Saturday. As the shortwave lifts to the NE, the trough axis will shift NE along with it, placing much of the state under the southwesterly flow aloft. This shift will also increase the chances for precipitation as a cold front moves eastward across the West Coast Saturday night. In addition, a low level jet is expected to set up by tomorrow morning, stretching from McGrath to the Yukon Flats, bringing chances for gusty winds during the day. Any areas that continue to see precipitation may not get as much surface heating, which may limit how much of those strong winds reach the surface. Elevations above 1500ft could see gusts peaking around 40 mph with gusts to around 30 mph at lower elevations. The strongest winds will be in the afternoon, around peak heating.

Looking back over the Bering, an upper-level low will continue to spin over the Bering Strait and begin to start shifting N/NE by Saturday night. This is also the main driver that is bringing the previously mentioned cold front across the state. With this low moving north, portions of the West Coast and North Slope will see a slight decrease in temperatures with a colder airmass moving SE from Siberia. Some of the energy from this low moving up the Arctic Coast will get wrapped back into another shortwave bringing the cold airmass over the West Coast. In addition, another streamline of vorticity will be moving north, with a SW-NE orientation, at the same time as the next low works its way across the West Coast. This will continue to support chances for isolated showers for the Central and Western Interior through the end of the weekend. This energy will be moving north with the help of another building ridge over the Alaskan Panhandle. In addition, another low will be moving north toward Kodiak Island by Monday afternoon. These could work together to set up another round of gusty winds through the Alaska Range and Tanana Valley by Tuesday. More on this in the extended portion of the discussion.

EXTENDED FORECAST DAYS 4-7

As previously mentioned in the forecast discussion, a low will be traveling northward along a ridge over northwest Canada, reaching Prince William Sound on Tuesday. As a result, upper-level winds will be angled southerly across the Alaska Range again Tuesday morning. We expect gap winds through the Alaska Range to strengthen, potentially to High Wind Warning criteria once again. However, this low is fairly transitory meaning the strongest winds should be less persistent going past Tuesday. In addition to the strong winds, the low will bring widespread precipitation to the Western and Central Interior. The eastern Interior should remain drier due to downsloping from the Alaska Range. Precipitation should continue north across the Brooks Range and North Slope by the end of the Day Tuesday.

At this point, the upper-level and surface features of the low split off from one another. The surface low spreads out across the north slope and Canada, while the upper-level low gets tangled up with another upper-level low over the northwest Arctic Coast. This amalgamated low will linger over the West Coast resulting in colder temperatures for the West Coast and Western Interior through the rest of the extended period. Models diverge towards the end of the week regarding the strength and path of the low, but the trend appears to favor the GFS solution in which the low weakens and is pushed to the northeast as high pressure looks to build in over the majority of the state by the end of the week. As a result, we should see generally warmer temperatures for most of Alaska by the end of next week.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Blizzard Warning for AKZ801. High Wind Warning for AKZ837-849. Wind Advisory for AKZ847. PK...Brisk Wind Advisory for PKZ809>811. Brisk Wind Advisory for PKZ812. Brisk Wind Advisory for PKZ813-815-858. Brisk Wind Advisory for PKZ814. Brisk Wind Advisory for PKZ854. Brisk Wind Advisory for PKZ857. Brisk Wind Advisory for PKZ859>861.