Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 449 PM EDT Fri Aug 12 2022 Valid 12Z Tue Aug 16 2022 - 12Z Sat Aug 20 2022 ...Cool/wet-to-snowy pattern for the North while rounds of heavy rainfall likely across the South & Panhandle... ...Guidance/Predictability Assessment... The guidance maintains the pattern of a the western AK upper trough/upper low, which causes cyclones to navigate around its periphery through the Aleutians towards Southern AK. The guidance shows relatively good agreement, so used a compromise of the 12z GFS, 12z Canadian, 12z UKMET, and 12z ECMWF for the pressures/500 hPa heights/winds mid next week and a combination of the 12z ECMWF/12z GFS/12z Canadian/00z ECMWF ensemble mean/12z NAEFS mean to deal with detail issues and uncertainty late next week which led to reasonable continuity for a forecast at that range. The grids were derived from the 19z NBM except the QPF, which weighted towards deterministic guidance for realistic amplitudes. ...Sensible Weather... Cooler air from the Arctic remains across the North 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 and the AK panhandle through the foreseeable future as south to southwest flow off the Pacific continues around the southeast and eastern peripheries of the closed mid-level low. Local amounts of 6"+ are possible from this system in the favored topography early and mid next week. Meanwhile, the central portion of Alaska should be sheltered from significant rain chances/amounts. However, with the upper trough across the west and cyclone moving in from the west and south, much of the state should be cloudy. Cool air from the Arctic will continue chilly conditions along the North Slope 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 to warm, with temperatures peaking in the 60s each day. Roth - Heavy rain across portions of the Alaska Panhandle and mainland Alaska, Mon-Fri, Aug 15-Aug 19. - Much below normal temperatures across portions of mainland Alaska, Mon-Wed, Aug 15-Aug 17. 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