Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 522 PM EST Sat Dec 28 2024 Valid 12Z Wed Jan 01 2025 - 12Z Sun Jan 05 2025 ...Overview with Guidance Evaluation and Preferences... Agreement among ensemble means from global models remain relatively well in depicting a tilted omega blocking pattern across the Alaskan domain gradually lifting northward across mainland Alaska and then evolving into a closed high over the Arctic Ocean during the medium-range forecast period. Much of mainland Alaska will then be under an upper-level col for the first few days of 2025. Today, models begin to indicate the possibility for an upper-level vorticity center to develop over northwestern Alaska and then slide southwest into the Bering Sea by next weekend. There was also a tendency for a stronger upper high to develop over northeastern Siberia late next week to the southwest of the high over the Arctic Ocean. Meanwhile, the main cyclone tracks will remain well south of the Gulf of Alaska. These cyclones show a tendency to weaken as they head toward the Gulf. A deeper cyclone will appear to slide south of the Aleutians through the latter half of next week, likely broadening and strengthening the northeasterly flow across the Bering Sea and through the Aleutians. The WPC forecast was based on a consensus blend of the 12Z GFS/GEFS, 12Z ECMWF and 00Z/12Z EC mean, and the 12Z CMC/CMC mean. This solution maintained good continuity with the previous WPC forecast package. The 06Z GFS did not appear to agree with the rest of the guidance regarding the individual cyclone tracks and thus was not included in the blend. ...Weather/Hazards Highlights... No hazardous weather is anticipated for the Alaskan domain through the medium-range forecast period. Much of mainland Alaska will be under a dry and persistent east to northeasterly flow near the surface with only modest amounts of precipitation along the southern coastlines including the Panhandle and the Aleutians. A stronger low pressure system edging closer toward the Gulf of Alaska could provide a period of gustier winds to the southeastern coastal sections of the Alaska Peninsula and Kodiak Island on Tuesday before sliding off to the east and weakens. The ECMWF solutions including its AI version favor a closer approach of this cyclone to the eastern Aleutians. By the latter half of next week, a general increase in precipitation chances and amounts can be expected for the western and central Aleutians when a deeper cyclone is predicted to slide to the south. After recovering from temperatures well below normal levels early in the week across the North Slope, a persistent east to northeasterly flow being fed by a strengthening surface high pressure system centered over the Arctic Ocean (with central pressure possibly above 1050 mb) late next week will keep temperatures below normal for much of mainland Alaska. Minimum temperatures may drop below -40 degrees daily over the Yukon Flats. Above normal temperatures will be confined farther south across the Alaska Peninsula, all of the Aleutians, and along the southern coastlines and scattered locations for the Alaska Panhandle. Kong 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