031 FXAK68 PAFC 310158 AFDAFC Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 458 PM AKST Tue Dec 30 2025 .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3/Tonight through Friday)... Ridging in the Bering Sea and troughing over Southcentral and the Gulf of Alaska continue to define the upper-level pattern this afternoon. The trough is anchored by a vertically-stacked low pressure system in the east-central Gulf, while a closed upper- level low sits over interior Alaska. Conditions are largely cold and dry across Southcentral as the Gulf low slowly tracks toward Southeast Alaska. This will be punctuated by some light snow as a band of precipitation extending from the Susitna Valley across the Alaska Range into the Interior drops south tonight, aided by the closed upper-low to the north swinging a shortwave trough across Southcentral. Light snow is most likely near the Alaska Range, with accumulations up to an inch or so possible along the Denali Highway and near Paxson. Some flurries and lighter accumulations are possible further south in the Matanuska Valley and even Anchorage (the best chance would be on the Hillside and higher elevations of Eagle River) later this evening as the snow works its way south. By around midnight tonight, this band of precipitation will begin to interact with the moist easterly flow wrapping around the Gulf low and bring slightly heavier precipitation to Prince William Sound and portions of the Copper River Basin. Meanwhile, a separate potent shortwave trough tracking over the top of the Bering ridge digs southeastward across Southwest Alaska and digs into the western Gulf tonight into Wednesday. Cold advection associated with the trough spreads across Southcentral, with winds already increasing through the coastal mountain gaps this evening. Wind gusts in Whittier already approaching 65 mph are reducing visibility to one half mile by lofting low density snow that fell earlier this morning. Low visibilities look to continue through the night, at minimum, until the transportable snow is mostly scoured out. While the strongest area of cold advection will be across the Alaska Peninsula, the western Gulf coastal waters, and Kodiak Island, cold air deepens across the rest of Southcentral as well, so gap winds look to ramp up again through Wednesday (New Year's Eve). Fortunately, one gap that will be spared with this northwesterly flow event is the Matanuska Valley, where winds will remain fairly light. Gusty winds, already ongoing through Thompson Pass, are also expected to reduce visibility to one half mile or less as snow returns after midnight. Visibility is expected to improve as now comes to an end across Prince William Sound and the Copper Basin Wednesday evening. In all, snow accumulations up to around 3 inches are expected near the coast, with decreasing amounts further inland/north. After that point, dry and cold conditions will settle back in across the region as the upper trough marches eastward. Gap winds will begin to gradually diminish Thursday into Friday with the loss of the upper-level forcing from the trough. Meanwhile, temperatures will gradually trend downward into the weekend. We are monitoring the potential for wind chills 40 below zero or lower developing across the Copper Basin and mountain passes of the Alaska Range as early as Wednesday night. By Friday, ambient temperatures in the single digits above and below zero are expected across the Cook Inlet region (Anchorage, western Kenai, Mat-Su) and even much of the north Gulf coast (including Seward, Whittier, Valdez, and Cordova). Meanwhile, the Copper Basin will likely be in the range of 20 to 30 below zero. Cold temperatures look to stick around through Monday next week. Quesada && .SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days 1 through 3: Today through Thursday)... A stout upper ridge is making slow but steady progress eastwards today, allowing dry conditions to spread across the central/eastern Aleutians and Pribilofs. Farther west, a front associated with an North Pacific low has pushed over the western Aleutians from the south, spreading low-end Gale force winds, and moderate rainfall into the western Chain. Across the AKPen, very strong and gusty north winds persist this morning, fueled by strong northerly flow between the Bering ridge and a deep low meandering across the Gulf. These strong winds will continue through tonight, remaining storm-force through the southern gaps and passes, through tonight diminishing Wednesday morning. Winds causing the resuspended ash from several of the volcanoes along the AKPen have diminished, and the ash is no longer airborne. The Bering front will continue to make steady northeast progress into the western and central Bering through midweek, spreading mainly rain across the Aleutian Chain as it moves across. Precipitation could start out as snow in the Pribilofs as the front moves in Wednesday afternoon, but a fairly quick transition to rain is likely by Wednesday evening as warmer air along the boundary pushes through. Across Southwest, a weak low and trailing front currently moving across the far northern Bering is on track to push a quick shot of snow showers across the Kuskokwim Delta this evening into early Wednesday. Moisture support for snow along this incoming front still looks unimpressive, with up to an inch of new snowfall for areas of the Kusko Delta anticipated as the front races past tonight, before deteriorating. Across the rest of Southwest, cold and dry conditions will persist through Thursday as north winds gradually die down. For the AKPen region, very strong and gusty northerly winds will continue today, weakening slightly by Wednesday, then coming down more sharply by Thursday as the Bering ridge erodes and as the Gulf low weakens. By the end of the workweek, a shift toward more active weather across the Bering Sea and Southwest coastline is expected with a broad trough moving in. No significantly deep lows on the horizon yet, however the passage of several shortwaves through the area may be the beginning of a longer term shift out of the high pressure benign pattern. -AS/CL && .LONG TERM FORECAST (Days 4 through 7: Friday through Monday)... Very cold, dry weather will persist into the weekend across mainland Alaska, while the Aleutians remain near- or just above-average in terms of temperatures thanks to a strong amplified upper-level ridge that remains in place across the central Bering Sea. Models are beginning to converge to a solution which features a deep low crossing over the Aleutians and into the Bering late Saturday into Sunday, helping shift that large ridge eastward a bit. Strong winds, large waves, and heavy precipitation are all a possibility with this low as it shifts north, with the strongest winds currently expected to be from approximately Atka west. For Southcentral, the main hazard for the weekend will be the continuation of strong gap winds through Sunday before the pressure gradient relaxes. Temperatures will be quite cold, with highs near 0 for Anchorage and the Kenai Peninsula, with lows closer to 10 below. The Copper River Basin will remain frigid, with temperatures largely hovering between 20 and 40 below. Models diverge, and thus confidence lowers, as we head into the beginning of next week. There's still reasonable consensus that a strong front associated with this low will rotate east into mainland Alaska, helping break down the ridge that would then be across the Gulf of Alaska north. A strong triple point low may also develop across the northern Gulf, which would bring heavy precip/snow to much of the Southcentral Coast. Details are still murky with this one, but this would ultimately be the next chance of significant snow accumulation for much of the area. Stay tuned. && .AVIATION... PANC...Gusty winds will finally die down today, slowly diminishing through the morning hours. A weak upper short-wave digging into Southcentral from the Interior tonight, will keep some clouds overhead, though mostly mid to high clouds. There is a just a slight chance of ceilings dropping to 5000 feet or a bit lower as the trough crosses overhead between 09Z and 15Z. && $$