Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 738 PM EDT Mon May 23 2022 Valid 12Z Fri May 27 2022 - 12Z Tue May 31 2022 ...Overview... An upper high centered over the Bering Sea late this week is forecast to slowly shift eastward over the mainland by early next week. This blocky high will separate an upper low well northwest of Alaska that may send rounds of troughing into the northern mainland from a train of lows and upper-level energy in the North Pacific. Generally light precipitation is forecast with this pattern, especially for the western mainland under the ridge influence, until early next week when energy spilling southward west of the ridge could produce a low pressure system closer to the Aleutians and the southern mainland along with higher rain chances. ...Guidance/Predictability Assessment... Model guidance remains in generally good agreement with the fairly slowly evolving pattern described above, especially with the blocky ridge initially across the Bering Sea shifting into the mainland. Model agreement in today's 12Z guidance has become better with the orientation of the upper low in the northern latitudes, and agree that most energy spilling southeastward from it around the high should likely be east of Alaska into northwest Canada. Meanwhile there are some uncertainties with the details of North Pacific energy late this week, though nothing too egregious for the medium range time frame. However as energy spills across the Russian Far East around Saturday, models diverge somewhat with its track as an upper low/trough forms early next week--with the CMC taking it eastward while the GFS and ECMWF are more agreeable with the feature diving south and then eventually east. Then there are some remaining questions about the feature phasing with energy already in the North Pacific, as well as the track of resulting surface low(s), but there is general consensus for a surface low to track closer to the Aleutians and southern Alaska. Since the 12Z guidance was in reasonable agreement, the WPC forecast blend for the early part of the period was based on deterministic guidance led by the GFS and ECMWF, and added in influence of the GEFS and EC ensemble means to about 40 percent by the end of the period. ...Weather and Hazard Highlights... Generally light precipitation is forecast for Alaska through next week, with one area of focus over the North Slope and Brooks Range as frontal systems linger there. The eastern mainland and parts of the Panhandle will also see rounds of light showers. Western Alaska could remain dry initially given the ridge pattern, but precipitation may increase early next week for the Aleutians and Alaska Peninsula spreading into the southern mainland as low pressure may approach. Periods of warmer than normal temperatures are expected for the western mainland into the central part of the state under the upper ridge influence. Parts of the Panhandle and the far southeastern mainland will likely be cooler than normal, while the North Slope could see a mix of above and below normal temperatures. Tate No significant hazards are expected over Alaska during this forecast period. 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