Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 547 PM EDT Mon Jul 19 2021 Valid 12Z Fri Jul 23 2021 - 12Z Tue Jul 27 2021 ...Guidance/Predictability Evaluation... Today's WPC Alaskan medium range product suite was primarily derived from a composite blend of reasonably well clustered guidance of the 12 UTC GFS/ECMWF/Canadian/UKMET and the 19 UTC National Blend of Models for days 4/5 (Friday-Saturday). Overall predictability seems above normal for this period, but increasing forecast spread into early next week seems best addressed by the still compatible 12 UTC GEFS/NAEFS/ECMWF ensemble means. WPC continuity is well maintained with this strategy in conjunction with manual adjustments to ensure low depth consistent with favorable upper support and predictability over the Gulf of Alaska. ...Weather/Threats Highlights... A fairly stagnant high latitude pattern will feature a Bering Strait closed low/trough that would support lingering precipitation chances with ejecting impulses over northwest Alaska and into the Brooks Range as a shielding/warming upper ridge settles over eastern portions of the Interior/North Slope. A less certain system track emerges by the weekend into the north-central Bering Sea and lead affects may reach western Alaska early next week. A modest undercutting system track offers some timing/focus variance, but should keep the southern Bering Sea, Aleutians, Southwest AK and the Alaskan Peninsula/Kodiak Island unsettled. This flow works into a lead Gulf of Alaska closed low/trough position. Main surface low positions there hold offshore and associated frontal systems will present an extended maritime weather focus. Less defined impulses rotating around the larger main circulation should periodically enhanced precipitation inland over southeastern and south-central Alaska, as well as farther inland into the southeast Interior underneath the ridge. Schichtel Hazards: 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