Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 634 PM EST Tue Jan 11 2022 Valid 12Z Sat Jan 15 2022 - 12Z Wed Jan 19 2022 ...Guidance/Uncertainty Assessment... Generally, the synoptic pattern for this cycle shows average to above average agreement across Alaska. Early on, a pair of weaker shortwave troughs will pass through, one affecting the southern mainland while another wave lifts into the Panhandle region. Both of these systems gradually become absorbed into the mean flow. Afterward, guidance continues to show a deep, large closed low settling across the western Aleutians becoming occluded by day 4. Model spread within this feature is high, with several embedded pieces of vorticity rotating through the flow that are difficult to time and pinpoint in the time range. There are signals of low pressure developing on the southern periphery of this system that then lifts northeast toward the mainland. Most of the deterministic models have this signal but with wide range in timing and track. As a result, the WPC blend initialized with a blend of the latest available deterministic guidance but then became heavily weighted towards the ECENS and GEFS means for days 6-8 given the higher than normal spread and affects to sensible weather. ...Weather/Hazard Highlights... A series of low pressure systems will impact the Alaska panhandle for the first few days of the medium range period, the first arriving late on day 3 into day 4. It is quickly followed by another system for the 16th/17th, both of which could bring widespread moderate to locally heavy precipitation (mountain snow, valley rain) as well as high winds and waves along the coast. The rest of the mainland is expected to be relatively dry (a weakening system will pass through the southern mainland days 3-4) as a closed low settles over the Aleutians. By the end of forecast period, waves of low pressure will become possible underneath the closed low and this could bring widespread precipitation to the eastern Aleutians and the southern mainland days 7-8. Some of this precipitation could be heavy along with high winds and waves. Taylor Hazards: - Heavy precipitation across portions of the Alaska Panhandle, Fri, Jan 14. - High winds across portions of the Alaska Panhandle, Fri, Jan 14. 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