Alaska Extended Forecast Discussion National Weather Service College Park MD 640 PM EST Tue Dec 9 2025 Valid 12Z Sat 13 Dec 2025 - 12Z Wed 17 Dec 2025 ...Overview... The large scale pattern over Alaska during the upcoming medium range period will be rather stagnant as an omega block sets up over the region. This is anchored by a mid-upper level high over the Bering Sea, with height anomalies over 3 standard deviations above normal. This will maintain troughing over eastern Alaska into the Gulf, as a couple of low pressure systems rotate into the Gulf. Moisture will funnel into Southeast Alaska for the weekend into Monday associated with a cold front. Additionally, northerly flow on the backside of the Gulf low(s) could lead to strong gap winds for the weekend into early next week. ...Guidance Evaluation and Preferences... The guidance continues to show reasonably good agreement on the overall pattern through much of the period. The upper high will meander over the Bering Sea the entire period. To the east, a vortex will drop south across eastern Alaska to form a deep trough/closed low over the Gulf. Energy south of the Aleutians will rotate into the Gulf low to help reinforce it into next week. The main uncertainties during the period are in the details of these individual shortwaves/lows into the Gulf and with the overall ridge/trough interface location. A blend of the deterministic guidance served as a good starting point for the WPC forecast today, with increasing weighting of the ensemble means for the latter half of the period. ...Weather/Hazards Highlights... Mean low pressure for the Gulf over the weekend and into early next week should lead to moist southwesterly flow into Southeast Alaska for some precipitation. Cold temperatures in place will mean most of this precipitation falls as snow, and moderate snow totals are likely on Sunday and Monday especially. Behind the mean surface low, strong gap winds are possible given the tight pressure gradient. While the details are still uncertain, the pattern for northerly gap winds will be favorable across the Alaska Peninsula toward Cook Inlet and Prince William Sound. Outflow winds are also possible for portions of Southeast Alaska in the Yakutat and northern Panhandle vicinity. High wind areas are in place on the Day 3-7 Hazards product. Temperatures for much of Alaska will trend much colder through the period, with anomalies 20-40 degrees below normal expected by the middle of next week. This could mean daily min temperatures as low as -40 for parts of the eastern Interior, and near or below zero for southern locations such as Anchorage. Southern parts of the Panhandle may not be as anomalous as the rest of the state due to relatively warmer moist inflow. And across the North Slope, temperatures should be near or above normal. Santorelli Additional 3-7 Day Hazard Information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range Alaskan products including 500mb, surface fronts/pressures progs and sensible weather grids can also be found at: https://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif https://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml https://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html