Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 408 PM EDT Tue Aug 09 2022 Valid 12Z Sat Aug 13 2022 - 12Z Wed Aug 17 2022 ...Cool/wet-to-snowy pattern for August returns this weekend across the North while rounds of heavy rainfall likely across the South... ...Guidance/Predictability Assessment... The guidance shows better than usual agreement into mid-next week as an upper trough edges across western AK and a cyclone yo-yos between AK and the northeast Pacific. Since agreement was so good, used a compromise of the 12z GFS, 12z Canadian, 12z UKMET, and 12z Canadian for the pressures/500 hPa heights/winds early before bringing in 12z NAEFS/00z ECMWF ensemble mean input late which eventually compromised 50% of the blend. Most of the grids were derived from the 19z NBM except the QPF, which weighted towards 12z GFS, 12z Canadian, and 12z ECMWF guidance for realistic amplitudes. ...Sensible Weather... After a brief warm up late this week, much cooler air from the Arctic is forecast to filter across the North by this weekend with high-elevation snow possible over the Brooks Range. Meanwhile, the greatest threat of heavy rain will be focused along the coastal sections and nearby high terrain of south and southeast Alaska late this week with the passage and return of an occluded cyclone. This cyclone is forecast to wander south before returning north early to mid next week, generally maintaining its strength. The Panhandle should see a period of enhanced precipitation moving in early next week. Local amounts of 5"+ are possible from this system in the favored topography between late this week and mid next week. Meanwhile, the central portion of Alaska should be sheltered from signifcant rain chances. However, with the upper trough across the west and deep layer cyclone hovering near to offshore southern AK, much of the state should be cloudy. There might be windows of opportunity for partly cloudy skies in the west from time to time. Some of the moisture from the southern coast is forecast to penetrate and move across the interior Southeast early next week. Cool air from the Arctic will bring chilly conditions into the North Slope by the weekend with snowfall possible over the Brooks Range. The polar air is forecast to show limited southward penetration down the west coast but should remain across the North Slope into early next to mid next week. The interior will be mild, with temperatures peaking in the 60s and 70s each day. Roth/Kong 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