Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 703 PM EST Sat Jan 25 2025 Valid 12Z Thu Jan 30 2025 - 12Z Mon Feb 03 2025 ...Much colder temperatures likely mid to late next week along with gap winds... ...Overview... An amplified and fairly progressive pattern is likely for Alaska through the extended period. An upper trough axis will be atop the Mainland to the Gulf midweek, with precipitation likely for Southeast Alaska on the eastern side of the trough while northwesterly gap winds affect parts of the Alaska Peninsula/Kodiak Island and surrounding waters. Much colder temperatures compared to the near term/short range are expected under the trough, but an upper ridge moving into western Alaska late week and central Alaska next weekend should lead to warming temperatures once again. Moist inflow east of Bering Sea troughing just behind this ridge will increase precipitation chances across the Aleutians, Alaska Peninsula, and western Mainland late week into next weekend. ...Guidance Evaluation and Preferences... Most model guidance shows good agreement with the pattern described above. The exception continues to be the CMC runs that spill more Arctic energy into the western side of the first trough as it moves across the central and eastern Mainland during the latter half of this week, which widens and maintains troughing over the Mainland for longer than other guidance. With the GFS and ECMWF and their ensemble means as well as the UKMET during its period more agreeable in the trough axis proceeding east, favored that larger cluster rather than the slow CMC runs. Surface low(s) in the Gulf and vicinity show a bit more model spread, but a multi-model blend seemed to work okay. Then there is good agreement for a surface high to strengthen in the northern half of Alaska Friday and western Canada into the weekend. Upstream, the GFS/EC/ensemble mean blend worked well for the upper ridge behind the first trough. There is more spread with the details of what models generally show as troughing over the Bering Sea across the Aleutians into the northern Pacific, along with associated surface lows, but this is to be expected by Days 6-8. Included the GEFS and EC ensemble means in the model blend and increased their proportion to 60 percent by Days 7-8 amid increasing uncertainty. ...Weather/Hazards Highlights... Surface lows/frontal zones are likely to help focus Pacific moisture inflow for moderate to possibly heavy precipitation in Southeast Alaska Wednesday with some precipitation lasting into Thursday. Meanwhile northwesterly flow is likely across the Alaska Peninsula toward Southcentral, which could funnel in typical areas like on either side of Kodiak Island to create strong gap winds peaking Wednesday-Thursday. Then frontal systems and lows will be tracking across the northern Pacific/Aleutians/Bering Sea, leading to precipitation spreading across the Aleutians and Alaska Peninsula late week and gradually into the western and central Mainland next weekend. Temperatures will become much colder by midweek for all areas except the North Slope and Southeast Alaska. Periods of cold highs staying in the -20s in the Brooks Range and parts of the Interior with lows approaching -40. Coldest anomalies should continue to nudge eastward a bit during Thursday-Friday. By the weekend, western areas are likely to start to warm up under the upper ridge. 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