187 FXAK69 PAFG 231559 AFDAFG Northern Alaska Forecast Discussion National Weather Service Fairbanks AK 659 AM AKST Sun Feb 23 2020 SYNOPSIS... Highlights are: Cold winds chills, SE winds 15 to 25 mph and low visibility in snow and blowing snow along the West Coast will taper off by afternoon as winds decrease and temperatures increase. Cold winds chills in zone 201 will continue through Mon AM, and spread to zone 202 from midnight tonight through Mon AM. Light snow over the Eastern Interior will diminish from the west today. The Alaska Highway from Tok to the Alcan Border with see NW winds 15 to 25 mph and snow and blowing snow today. The Richardson Highway from Trims Camp south, and the Parks Highway south of Denali Park Entrance will see similar conditions today. Clearing over the Western and Central Interior has allowed temps to fall into the 20s and 30s below this morning, with these cold temps moving into the Eastern Interior tonight. Expect well below normal temps most of Northern Alaska this week. Aloft... A strong trough aloft from Wrangel Island to the Eastern Gulf of Alaska will move to Utqiagvik to Big Delta by 3pm Sun, to Barter Island to Northway by 3am Mon, and east of the Alcan Border on Mon. Light snow east of this trough will taper off along the trough with clearing west of the trough. Expect an inch or less of snow with this over the Eastern Interior today. Surface temps will fall into the 20s and 30s below in the clearing west of the trough. A ridge aloft stretching from the Western Gulf of Alaska into the southeast Bering Sea will build over southern Alaska Mon and Tue. This will keep skies partly to mostly cloudy, and keep most clouds and weather over the West Coast and North Slope for Mon and Tue. 850 MB temps are colder than -20C over most of Northern Alaska, with warming over Western Alaska Sun and Mon, with slight warming over the remainder of Alaska Mon night and Tue. Surface... A 997 mb low near Wrangel Island will move north today and tonight. A low pressure trough that lies from this low to north of Utqiagvik to MacKenzie Bay will move north tonight and Sun. Flurries and light fog along this feature will move north of the coast this afternoon. A weather front from the Wrangel Island Low Point Hope to the Bering Strait then southwest will move east to Barter Island to the Bering Strait to a 1018 mb low in the Gulf of Anadyr by 3pm Sun, with that low moving to near POint Hope as a 1023 mb low by 3am Tue. There is snow and blowing snow, and SE winds 15 to 25 mph along this feature over the West Coast now that will taper off this afternoon. Snow will redevelop along the front tonight and Mon bringing snow to zone 213 tonight and Mon and to NW Alaska on Mon night and Tue. Expect 1-3 inches of snow with this. && .DISCUSSION... Models verify well aloft at 00Z, and show similar solutions aloft through 3pm Mon. After that time, the GFS and NAM have a short wave in the Gulf of Alaska further east than the ECMF. At this time favor the GFS and NAM solution. Due to the strong dynamics associated with this feature which would allow it to dig into the ridge, we favor the GFS and NAM solutions over the ECMF for Mon night and Tue. At the surface at 06Z, the low near Wrangel Island it about 8 MB deeper than any models indicate, and the wave near the Bering Strait is also several MB deeper than any models indicate. Expect lower pressures than models indicate in those areas to persist through noon today, then to come more in line with models tonight as the Wrangel Is low moves north. The affect of this is that winds along the West Coast are much stronger than models indicate now, especially along the wave low near the Bering Strait. Those winds should remain stronger than models indicate through this afternoon, then come more in line with models tonight. With precipitation, models show similar solutions through Mon, with slight differences on Mon night and Tue. We will use a blend of model precip fields for pops and amounts. All the models are too low with pops along the West Coast now. We will bump pops up to likely along the West Coast west of Golovin and Kivalina where precip is occuring now, with likely pops moving into the remainder of the West Coast this morning. Bottom line is we will use a blend of the NAM, GFS and ECMF for precip but bump up pops to likely today along the West Coast, and we will use a blend of the NAM and GFS for surface temps and winds, but increase winds 10 kt (and 15kt at Capes) in a narrow band ahead of the incoming wave along the West Coast today. Coastal Hazard Potential Days 3 and 4...None. && .AFG WATCHES/WARNINGS/ADVISORIES... Wind Chill Advisory for AKZ201-AKZ202-AKZ207-AKZ209. Winter Weather Advisory for AKZ213-AKZ214. Brisk Wind Advisory for PKZ200-PKZ210-PKZ220-PKZ225. && $$ JB FEB 20 |