Area Forecast Discussion
Issued by NWS Anchorage, AK
Issued by NWS Anchorage, AK
544 FXAK68 PAFC 290127 AFDAFC Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 427 PM AKST Fri Nov 28 2025 .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Tonight through Monday)... An upper level shortwave trough stretching from the western Alaska Range to the northern Gulf continues to make steady northeast progress into Southcentral this afternoon. A swath of moisture has moved up into the Copper Basin, where forcing and lift ahead of the incoming trough are supporting widespread light snowfall. Farther south, warmer temperatures are yielding mostly cold rain near Valdez and Cordova near sea level. Behind the trough passage, the western half of Southcentral is clearing out as a transient upper ridge begins to build into place from Southwest. Patchy areas of fog have developed where calm winds and clear skies have helped the near surface air radiate and cool to saturation. So far, this has been mostly concentrated across the western Kenai Peninsula. However, areas farther north into Anchorage could easily fog up later this evening as temperatures cool off a few degrees under clear skies and light northeast winds. Saturday will mark the beginning of what could truly be described as a prolonged stretch of weather chaos. A strong warm front associated with a large low moving over the North Pacific is expected to lift across the Gulf throughout the day, sending a renewed surge of moisture and lift straight north into Southcentral. Precipitation will overspread much of the outlook area from south to north, first reaching Kodiak and the Kenai Peninsula early in the morning, then spreading into the interior later in the day. A nose of warm air will move in aloft as temperatures above freezing stream northwest overtop of cooler temperatures in place across the Mat-Su, Anchorage and western Kenai Peninsula right around the same time precipitation moving in ahead of the front arrives. This will create a favorable temperatures profile for a wintry mix of sleet, snow and freezing rain, roughly along an axis from Anchor Point up to Willow and Palmer. Winter Weather Advisories are now set to go into effect midday Saturday for this entire corridor. Across the Winter Weather Advisory areas, icing amounts do not look likely to be all that significant (no more than 0.10") due to a couple limiting factors. First off, increasing easterly flow will increase downslope drying with time, limiting precipitation intensity. Secondly, east to northeast winds will pick up sharply at the surface by Saturday evening as a northeast to southwest pressure gradient tightens ahead of the approaching frontal wave. This will tend to increase mixing with time, allowing temperatures to warm a few degrees above freezing across most of the Mat Valley, Anchorage and western Kenai Peninsula from Saturday night into early Sunday. However, there could be a few cold pockets that linger into Sunday where winds do not materialize, such as east Anchorage and the southern end of the Susitna Valley. This could allow isolated areas to still see occasional periods of freezing rain lingering into much of Sunday. Looking more into the start of next week, the active and warm pattern shows no signs of abating. From Sunday into Monday, a shortwave trough and attendant surface low will move north into the eastern Gulf as the front moves into the Gulf coast and weakens. Models have struggled mightily to hone in on the track of this system, though there has been a fairly distinct west shift for the expected trajectory of this system. The consensus is that the low will stall just south of the the Kenai Peninsula, then possibly shift more northeast towards Prince William Sound as the upper trough continues to lift north somewhere over the eastern half of Southcentral. This could actually favor a period of accumulating wet snow across the western Kenai Peninsula up into Anchorage and the Matanuska Valley, depending on exactly where the upper trough tracks and how much temperatures can cool back down in the lower levels as precipitation moves back in from the west. It is worth emphasizing, however, that this is a complex pattern with a lot of room for more changes to how things evolve. Be sure to monitor the forecast for updates as we continue to follow this very active pattern into early next week. -AS && .SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days 1 through 3)... **Key Message: A Winter Storm Watch has been issued for the Kuskokwim Delta and Kuskokwim Valley from late Saturday night through Tuesday afternoon for up to 2" of snowfall and up to 0.25" of ice accumulation.** Diving into the details, satellite imagery reveals a rather large gale force low with its front driving northward from the North Pacific towards the eastern half of the Aleutian Chain. Gale force winds with up to storm force wind gusts overspread the Chain tonight. A couple areas of interest will be Cold Bay and Dutch Harbor. Cold Bay`s favorable southeasterly wind direction funneling through the terrain there will lead to strong, gusty winds. Meanwhile, Dutch Harbor is especially vulnerable to a southeasterly to easterly wind direction, and the peak duration of winds will likely be Friday evening through Saturday morning. Upper level features disagree on placement and timing, but the bottom line is by Saturday afternoon, frontal precipitation drives into the Bristol Bay region and coastal areas of Southwest Alaska. The airmass currently across Southwest Alaska is not terribly cold, but should be cold enough at the surface and aloft to support a quick round of snow or rain/snow mix for these locations before changing over to a period of freezing rain. The GFS and EC seem to be the colder solutions model wise, while the NAM is the warmest model. Forecaster confidence leans more NAM than the GFS and EC for a couple of reasons. First, southeast winds at the surface, 925 mb, and 850 mb will bring in a push of relatively warmer air for coastal Southwest Alaska. Secondly, freezing rain is a self limiting p-type, meaning latent heat of freezing will actually cause the airmass at the surface to moderate with no direct supply of reinforcing colder air to offset the warming. So, the idea for Bristol Bay areas will be a fairly fast snow to freezing rain to rain transition. It will take a bit longer for precipitation to move farther northward across the Yukon-Kuskokwim Delta, with most of the guidance indicating snow could fall Sunday morning. For these areas under the Winter Storm Watch, warm air intrusion will make its appearance also, though with temperatures well below freezing and surface winds shifting more northerly, a changeover to freezing rain will likely be a long duration event. For these locations, we will see a period of snow transitioning to freezing rain as a band sets up shop for the Yukon-Kuskokwim Delta region and points farther inland across the Valley. Because cold air is dense and wants to sink, this makes it tough to erode, so valley locations have increased freezing rain potential and could see more ice accumulation than nearby areas. Sunday morning, the gale force low devolves into a strong complex low pressure system, and the guidance suggests that an area of low pressure could form on its eastern periphery across the western Gulf. If this is the case, the low will retrograde northwestward and move across Southwest Alaska and send a second wave of moisture across the region, adding to what snow and ice has already fallen. The most uncertain part of the forecast is if this in fact materializes, and if it does, how much more warm intrusion will take place as surface winds northwest of the low shift to out of the northeast. Pattern recognition points to this re-estabilishing the warm nose effect, which would lead to another round of freezing rain and just plain rain for some areas that are a bit warmer. Precipitation will linger well into late Monday and Tuesday, as this system will likely be a long duration freezing rain/snow event for the Yukon-Kuksokwim Delta and Kuskokwim Valley. -AM && .LONG TERM FORECAST (Days 4 through 7 - Tuesday through Friday)... Uncertainty continues to be an issue in the long term. A North Pacific low is projected to track into the Bering Sea with the leading front bringing widespread precipitation and gale force to storm force winds from the northeast direction across much of the Bering Sea. Winds along the western periphery of the low will become northerly as it crosses the western Aleutians. Precipitation type is the main challenge for the mainland for the early part of next week as cool temperatures remain at the surface and warmer air filters across the region aloft. Although the low weakens in the southern Bering, it is not entirely clear how long this forecast challenge will persist through the rest of the week. This system appears to bring a prolonged pattern, especially for southwest Alaska with strong winds, precipitation, and warm southerly air moving over cool northerly air. For the Gulf and Southcentral, waves of surface lows and fronts will transit the Gulf, but some uncertainty remains to its strength and trajectory into the northern Gulf or eastern Gulf. At the least, expect showers to continue for coastal areas with less clarity for the long term weather conditions farther inland. Toward the last half of the week though, a strong front moves into the western Bering Sea from a Kamchatka low. Storm force gusts seem more likely along the front but may be stunted progress as it bumps into a narrow area of high pressure in the central Aleutians and Bering Sea. An upper level blocking pattern seems possible with high pressure to the north and areas of low pressure with embedded disturbances transiting south and along the Aleutians. Breezy gap winds across Southcentral will be possible for the latter half of the week. && .AVIATION... PANC...VFR conditions with ceilings above 5000 ft and light northerly winds will persist through this evening. Vicinity mixed precipitation showers are also possible this afternoon/early evening, although the bulk of any shower activity should remain east of the terminal. Fog and/or low stratus may also develop tonight as winds at and near the surface slacken while low-level moisture lingers underneath a transient ridge moving over the region. This introduces potential for IFR visibility through Saturday morning. Later on Saturday, any fog would be scoured out by increasing northerly winds. Precipitation chances then increase by Saturday afternoon with the arrival of another frontal system. Any steady precipitation would likely fall as freezing rain, with a glaze of ice accumulation possible. -TM/Quesada && $$