Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 636 PM EDT Sun Jul 18 2021 Valid 12Z Thu Jul 22 2021 - 12Z Mon Jul 26 2021 ...Guidance/Predictability Evaluation... The WPC Alaskan medium range product suite was primarily derived from a composite blend of well clustered guidance of the 12 UTC GFS/ECMWF/Canadian and the 19 UTC National Blend of Models days 4-6 (Thursday-Saturday). Overall predictability seems above normal through the period for much of the domain, but does increase enough into days 7/8 to be addressed by introduction of majority weighting of the more compatible 12 UTC GEFS/NAEFS/ECMWF ensemble means. WPC continuity is well maintained in this manner along with manual adjustments to ensure offshore low depth consistent with favorable upper support and predictability. ...Weather/Threats Highlights... A stagnant high latitude pattern will feature a Bering Strait closed low and upper trough that will support lingering precipitation chances for northwest Alaska and the Brooks Range through this period as a warming upper ridge settles over the eastern Interior/North Slope. An undercutting system track will keep the Bering Sea and Aleutians periodically unsettled and lead into a significant closed low and trough to anchor over the Gulf of Alaska. Main surface low positions offshore and associated frontal systems will offer a prolonged maritime weather focus while less defined impulses rotating around the larger circulation offers periodically enhanced precipitation inland for southeastern and south-central Alaska. Schichtel 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