Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 550 PM EST Mon Feb 17 2025 Valid 12Z Fri Feb 21 2025 - 12Z Tue Feb 25 2025 ...Overview... A parade of shortwaves and surface lows rounding the base of a broad trough/upper low in the Bering Sea/Aleutians will continue to bring an active/wet pattern to coastal portions of Alaska, particularly the Southern Coast and into the Southeast/Panhandle. The guidance shows three main lows within this pattern - the first into the southern Panhandle on Friday, another low into the Gulf/Southern Coast Sunday into Monday, and a third bigger low lifting north towards the Gulf next Tuesday. This should bring daily chances for moderate to locally heavy precipitation to these regions. Meanwhile, upper ridging will persist over much of the Mainland, bringing a period of much above normal temperatures across the state. ...Guidance Evaluation and Preferences... There continues to be general agreement on the large scale pattern described above, but a lot of variability and uncertainty with individual lows and shortwaves into the Southern Coast and Panhandle. This lends still to a low confidence forecast in the specifics, including track and intensity of any given low, but there is some noticeable consistency in the low pressure systems described above. This generally sets up a pattern of persistent onshore flow into Southeast Alaska. There was enough agreement early in the period for a multi-model blend. But increasing variability in low placements and tracks forced a gradual increase in the ensemble means into the blend by later in the period. The Day 8 blend included 60 percent ensemble means with 40 percent total of the 12z GFS, ECMWF, and CMC. This approach maintained reasonable continuity with yesterdays WPC forecast as well. ...Weather/Hazards Highlights... Multiple shortwaves rounding the base of the upper trough will lead to a generally wet pattern from the eastern Aleutians to the Southeast/Panhandle. The most likely focus for moderate to locally heavy precipitation remains across the Kenai/Prince William Sound region as well as the Panhandle as a series of surface lows affect these regions. Precipitation should be in the form of rain along the coast, but likely snow in the higher elevations. Some locations could receive several inches of rain over the several day period. A weak front through the interior portions of the state may also bring some light showers to some places. Upper ridging persisting through the period will keep temperatures well above normal through the period over the entire state, with some locations across especially southwest and southern Alaska possible to see daytime highs 20 to 30 degrees 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