Area Forecast Discussion
Issued by NWS Fairbanks, AK
Issued by NWS Fairbanks, AK
321 FXAK69 PAFG 251210 CCA AFDAFG Northern Alaska Forecast Discussion National Weather Service Fairbanks AK 406 AM AKDT Wed Sep 25 2024 .SYNOPSIS... Weather remains quiet and mostly unimpactful across Northern Alaska. An arctic trough will keep areas of light snow over the N Slope and Arctic through Thursday. Showers with snow levels between 1500 and 2500 feet will continue across the Interior. A mix of showers and mostly clear skies are expected across the West Coast. && .DISCUSSION... Analysis and Model Discussion... The 25/00z model suite initialized well with observations aloft and at the surface. Models are in good agreement through Saturday morning. Global models are running a bit too strong on winds on the West Coast. We will use a blend of the NBM and high resolution models for the winds, and a general blend of models with minimal hand edits for other elements. Aloft at 500 mb, an elongated north/south oriented upper level low lies over the West Coast with northerly flow to the west over the Bering Strait. Weak southerly flow is in place east of the low center, which is near Kotzebue. The low will migrate slowly to the west through the forecast period, with a ridge building over the central and eastern Interior Friday and Saturday. At the surface, gradients will remain mostly light. A NE/SW gradient across the West Coast will keep north/northeast winds of 15 to 20 mph in place there through much of the forecast period. A north/south gradient across the Brooks Range producing winds gusting to 25 mph through Anaktuvuk and Atigun Passes will weaken tonight. High pressure building over the Copper Basin will bring southerly gap winds through Alaska Range passes beginning late Friday night and early Saturday morning. Central and Eastern Interior...Quiet weather persists with highs near normal and lows above normal under cloudy skies. These conditions will persist through Friday. Patchy fog is expected this morning from Minchumina to McGrath and from Delta Junction east along the Alaska Highway. Shower coverage will decrease each day through Friday. Showers will be most numerous today and tonight over the Yukon Flats, tomorrow over the Fortymile Country, and Friday over the Upper Koyukuk Valley. Snow levels will be mainly between 1500 and 2500 feet, though a bit higher from Fairbanks southeast to the Alcan Border. Winds will be light except through Alaska Range passes beginning Friday. Highs will be in the 40s with lows in the 30s. Anecdote: The latest first freeze of the season on record at Fairbanks International Airport is September 27, 1974. Cloudy skies this week will make Saturday September 28th the first day where a freeze may be likely. Models are in good agreement that skies will be clear Saturday morning with a mid level dry slot moving north over the Alaska Range beneath the building ridge of high pressure, though gap winds through Alaska Range passes may be strong enough to produce modest adiabatic heating. At this time, a freeze appears likely on Saturday morning, but is far from certain. North Slope and Brooks Range...Snow showers are expected in the Brooks Range and north across the Arctic Plain today and tonight with an inch or less of accumulation. Along the coast, expect clouds with some areas of fog and low stratus to continue. A few light snow showers are possible mainly east of Deadhorse. Winds will be 15 mph or less. Highs will be in the 30s, except in the 20s over Brooks Range passes. Lows will be in the 20s and lower 30s. West Coast and Western Interior...Mostly sunny conditions along the coast today will transition to mostly cloudy overnight. North winds will remain around 15 mph through Thursday morning before increasing to around 25 mph through the Bering Strait. In the interior, rain and snow showers are expected today and will diminish in coverage overnight tonight. Snow levels will be near the surface. Highs everywhere will be in the low 40s with lows in the upper 20s and low 30s, except in the mid 30s at St. Lawrence Island. Coastal Hazard Potential Days 3 and 4...None. Extended Forecast For Days 4 through 7...Forecast models are in agreement that the extended forecast period beginning on Saturday will begin with a ridge in place and seasonably warm and dry conditions over the Central and Eastern Interior and North Slope, with showers and cooler conditions on the West Coast. These conditions will likely pesist until Tuesday when models show a low in the Bering Sea bringing a front to the West Coast. A potentially impactful low may follow in the Thursday/Friday timeframe, however there is still a lot of uncertainty on location and timing. The Interior looks to be much drier and cooler beginning on Saturday. A note on the first significant snow in the Fairbanks area: Ensembles show a large spread, but generally agree that the first measurable snowfall won`t be before the October 4-7 timeframe. GFS ensemble members all indicate some amount of measurable snowfall in Fairbanks by October 7. The ECMWF is less enthusiastic, but probabilities for measurable snow increase beginning around October 6. The average first measurable snow in Fairbanks is October 2 and the average first snowfall of one inch or greater is October 10. && .HYDROLOGY...No concerns. && .AFG WATCHES/WARNINGS/ADVISORIES... AK...None. PK...Small Craft Advisory for PKZ851. && $$ CHRIEST