Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 743 PM EDT Tue Jun 01 2021 Valid 12Z Sat Jun 05 2021 - 12Z Wed Jun 09 2021 ...Overview and Guidance Evaluation... A deep upper-level low is forecast to be located between northwestern Alaska and Siberia at the start of the medium-range period this weekend. The ECMWF and CMC tend to dig this upper low southeastward down the West Coast early next week toward the Gulf of Alaska. Their ensemble means do not support this scenario, however. A general model compromise was used to derive the WPC Alaska medium-range grids. This blend included the 12Z GFS/GEFS, 12Z CMC/CMC mean, and the 12Z ECMWF/00Z EC mean, trending toward the ensemble means for Days 7-8. With a general model compromise, the upper low is kept nearly stationary between Alaska and Siberia during the weekend before lifting and opening up into the Arctic Ocean, a scenario that agrees better with the GFS. But some troughing is maintained near the west coast of AK into early next week. Elsewhere, upper troughing and a surface front appear to linger near/south of the western Aleutians as weakening impulses push northward toward the area from the northern Pacific. This blend also agrees well with continuity. ...Weather/Threats Highlights... Some enhanced precipitation will linger across the Alaska Panhandle associated with weakening low pressure systems. Some moderate precipitation is also forecast near the Tanana River Valley in southeastern Alaska this weekend before diminishing early next week. Increasing chance of rain can be expected for western Alaska and the Aleutians early next week due to approaching frontal systems. Temperatures are expected to be above normal for western coastal sections of Alaska but below normal for the North Slope and for southern and southeastern Alaska. Much of the interior sections should see highs into the 60s but it will remain quite chilly north of the Brooks Range where highs should remain in the 30s and 40s. Kong Additional 3-7 Day Hazard information can be found on the WPC medium range hazards 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