Area Forecast Discussion
Issued by NWS Fairbanks, AK
Issued by NWS Fairbanks, AK
836 FXAK69 PAFG 200743 AFDAFG Northern Alaska Forecast Discussion National Weather Service Fairbanks AK 1143 PM AKDT Thu Sep 19 2024 .SYNOPSIS... An arctic trough digging south from the NW Arctic to the Interior will be the main weather concern over the next few days. Heavy snow is expected over the Brooks Range, with snow levels dropping to 1000 feet over the Interior this weekend. North winds behind the trough will keep the West Coast dry and storm-free. && .DISCUSSION... Upper Levels and Analysis... A 533 dam arctic trough is digging southeast across the NW Arctic this morning. There is a secondary basal shortwave trough over the Alaska Range and Southcentral. A 552 dam transitory ridge axis is over the Bering Sea. There is an elongated 998 mb low over the S Gulf of Alaska. There is a weak 1011 mb low approximately 100 nm N of Utqiagvik with the associated arctic front moving into the Lisburne Peninsula. Forecast and Model Discussion... The arctic trough over the NW Arctic digs southeast through Saturday, merging with energy and moisture over the Gulf of AK, bringing periods of rain and mixed snow as low as 1000 feet across the Interior to the southern slopes of the Brooks Range. Heavy snow will fall over the northern slopes of the Brooks Range to the crest, with 6 to 12 inches from Umiat to to the Dalton Hwy corridor. Models are fairly well clustered but the NAM 00z is a significant outlier with the track of the arctic trough, with the NAM much further south. We will favor a ECMWF/Canadian/ICON/NBM blend to bring in snow chances down to 1000 feet for the Interior. Central and Eastern Interior... Isolated to scattered showers today will consolidate into more organized rain showers Saturday, mainly along and east of the Parks/Elliot Hwy corridors to the Alaska Hwy. Mixed snow will be possible Saturday down to 1000 feet, but any accumulations will likely be 1500 feet or higher. Generally looking at 1 to 2 inches of snowfall above 2000 feet, possibly 3 inches or more over the higher elevations of the Steese Hwy. Otherwise, it will be mostly a cold rain with a possible stray snowflake over the Tanana Valley. Saturday night and Sunday it will be drying out as the trough axis shifts north, although rain/snow shower chances will persist over the higher terrain, while drier northeast winds move into the remainder of the Interior. Lows each night after tonight will be dropping into the low 30s and colder for Interior valleys, so any remnant plants should be brought in. West Coast and Western Interior... Sporadic light rain showers over the coastal regions will move inland today then end by tomorrow. An arctic trough will dig into the Interior and will bring northeast winds to the region, keeping it dry through the weekend. Over coastal regions, the northeast winds are quite brisk by Sunday, with 15 to 30 mph winds expected. Temps will be on the downtrend with the colder air moving south. North Slope and Brooks Range... An arctic front shifts east across the region, and the arctic low will shift south, bringing heavy accumulating snow to the Brooks Range and the plains to the north, from Umiat to the Dalton Hwy Corridor, including Toolik Field Station. Precip may start as mixed rain/snow this morning, but will turn to all snow above 1000 feet. Coastal regions will see mixed rain/snow showers with no accumulations. We expect 6 to 12 inches of snow accumulations, and we will upgrade the winter storm watch to a warning for the Atigun Pass, Anaktuvuk Pass, and plains north of the Brooks Range. Upper troughing will remain so snow chances will go all the way into Monday, but the warning will be in effect for Friday morning through Sunday morning, even with lighter snow going into next week. Extended Forecast Days 4-7... Monday and beyond, arctic troughing will be in place over the Western Interior with a strong low moving into the Gulf of AK. Eventually warmer air will move back into the Gulf and will try and move north. This will likely keep rain/snow showers possible over the Mainland, especially the eastern half of the Interior. The W Interior looks drier with north winds, while the arctic air persists from the Brooks Range north. Snow chances continue into midweek for the Brooks Range and Arctic. Coastal Hazard Potential Days 3 and 4...None. && .HYDROLOGY... No concerns. && .AFG WATCHES/WARNINGS/ADVISORIES... AK...Winter Storm Warning for AKZ809. PK...None. && $$ Ahsenmacher