Alaska Extended Forecast Discussion National Weather Service College Park MD 627 PM EST Mon Dec 8 2025 Valid 12Z Fri 12 Dec 2025 - 12Z Tue 16 Dec 2025 ...Overview... The large scale pattern over Alaska will be anchored by a mid- upper high drifting over the Bering Sea, with height anomalies over 3 standard deviations above normal. On the eastern side of this ridge, shortwave energy is forecast to drop southward atop eastern portions of the Mainland late week/into the weekend and form troughing with a possible embedded upper low near the Gulf of Alaska, as the eastern side of an omega block. This shortwave and an associated frontal system should lead to some snow across the North Slope into the Interior particularly on Friday. Surface high pressure across Alaska will initially block strong Pacific cyclones from reaching the state, keeping precipitation limited elsewhere. But the upper trough/low formation over the Gulf could lead to lower surface pressures and moisture funneling into Southeast Alaska for the weekend into Monday. 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... Models show reasonably good agreement on the overall pattern described above early in the period. The upper high atop the southern Bering Sea Friday is forecast to drift northwest toward eastern Siberia over the weekend, coincident with vorticity moving south through the eastern side. The ridge/trough interface will be uncertain given the differences in how far west/east the energy drops south. A multi-model deterministic blend favoring the ECMWF worked well as a middle ground solution though. By Sunday and beyond, model differences increase with the result of the vort max(es) feeding into the Gulf and vicinity. The 12Z GFS and ECMWF aligned well with each other as well as the EC-AIFS in producing a Gulf upper low, but the CMC was farther east into western Canada with this energy, which was also reflected in the CMC ensemble mean. Leaned away from the lower probability CMC-type solutions at this point. Within the generally favorable pattern for surface lows to form underneath the upper trough/low in the Gulf, there is considerable spread in the details. The 12Z ECMWF seemed stronger than preferred by early next week as it took a surface low in the 950s mb toward Southeast Alaska. The details of these lows will affect sensible weather like the direction and strength of gap winds. The eventual evolution of upper energy will be dependent on the track of an Arctic upper low north of the state, which is also uncertain. Thus for now, the WPC forecast gradually increased the proportion of ensemble means to over half Days 7-8 given the increasing spread. ...Weather/Hazards Highlights... A round of light to moderate snow is likely for the North Slope, Brooks Range, and Interior late this week as shortwave energy passes over. Then as the shortwave develops into an upper low in the Gulf, the lowering heights will allow for surface pressures to decrease closer to the southern coast of Alaska. Mean low pressure for the Gulf over the weekend and into early next week should lead to moist southwesterly flow into Southeast for some precipitation. The 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 uncertain, the pattern for northerly gap winds will be favorable across the Alaska Peninsula toward Cook Inlet. Outflow winds are also possible for portions of Southeast Alaska in the Yakutat vicinity. High winds areas are in place on the Day 3-7 Hazards product. Temperatures will continue to be bitterly cold in the eastern Mainland into Friday morning, with lows in the -30s in areas like the Yukon Flats. Meanwhile milder than average temperatures are likely across the western Mainland and North Slope underneath the upper high, with near to slightly above average temperatures reaching across the Interior Friday and Saturday. But as the upper ridge edges westward and troughing returns to the south-central part of the state, colder temperatures will return by early next week, with widespread anomalies 20-40 degrees below normal. Fairbanks is expected to see another few days of temperatures staying well below 0F, while single digit highs are possible in Anchorage. Colder than average temperatures are likely across Southeast Alaska as well, though the southern parts of the Panhandle should see increasing temperatures as the period progresses due to the relatively warmer moist inflow. Meanwhile the North Slope looks to stay above normal most days, though the anomalies should not be as high as the late week period. Tate 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