Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 744 PM EDT Tue Apr 25 2023 Valid 12Z Sat Apr 29 2023 - 12Z Wed May 03 2023 ...Synoptic Overview... A strong upper low will slowly drop southward across the Bering Sea through the end of the week before settling near the central Aleutians by the start of the upcoming week. Meanwhile, a separate low pressure system from the central Pacific is expected to track towards the Gulf of Alaska and reach the general vicinity of the southeast Panhandle region by Sunday and weakening going into Monday. Upper level ridging will build in across western Canada and into far eastern Alaska ahead of the approaching Gulf low, and a separate ridge axis begins developing across the central Gulf early next week between the Aleutians low and the Panhandle low. ...Guidance Evaluation/Predictability Assessment... The latest run of the guidance continues to show some improvement in the clustering with respect to the strong low over the Bering Sea and also for the approaching low pressure system to the Panhandle/southern coast region. Some latitudinal differences remain with the core of the low, and some timing differences with shortwave energy pivoting around the southern periphery of that low. There is a hint that the low may be deepening toward the end of the extended period which could impact how much/how far inland the QPF spreads. Preferred a general blend of the NBM,12Z/06Z GFS, 12Z/00Z ECWMF, 12Z CMC and GEFS/EC ensemble means for the forecast suite. ...Weather/Hazard Highlights... A fetch of deep moisture will be directed onshore, spreading from the Southeast to southern Mainland this weekend as the mid-to-upper cyclone drops slowly across the Bering Sea. With the steady influx of moisture and the approach of the front to the Panhandle, there will be support for moderate to locally heavy rainfall in the lower elevations and snow in the mountains. The PW values will be nearing 0.75-1 inch which is approximately 2 std. dev. above normal for the end of April. This onshore moisture flux will also modify the cold air mass inland with highs reaching 45-55 degrees for many inland areas. A multi-day total of liquid equivalent precipitation may be 3-6 inch range in orographically favored locations remain in the forecast. The remainder of southern Alaska should remain unsettled overall as assorted cyclones impact the southeast Panhandle and the Alaska Peninsula. The various low pressure systems should lead to periods of gale force winds, with the possibility of some storm force gusts, across portions of the Gulf of Alaska and Bering Sea. The northern coast of Alaska also has the threat of gales late week into the weekend as the pressure gradient tightens over the region. Campbell/Hamrick 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