Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 653 PM EST Sun Feb 06 2022 Valid 12Z Thu Feb 10 2022 - 12Z Mon Feb 14 2022 ...Overview... An active storm track is expected in the northern Pacific south of the Aleutians late this week into early next week, with potential for relatively weaker surface lows to approach the Gulf and southern Alaska in southwesterly flow just east of an upper low/trough weakening over northwestern Alaska and the Bering Sea. These surface lows could enhance precipitation periodically in southern Alaska especially from the Kenai Peninsula into the Panhandle. The largest and deepest surface low should track south of the Aleutians (likely somewhere between 40-50N latitude) early next week, but given its breadth could still affect the Aleutians with high winds, rough seas, and precipitation. ...Guidance/Predictability Assessment... Recent model guidance still shows an upper low near the Bering Sea/western Alaska embedded within an elongated upper trough over northern and western parts of the mainland to start the period Thursday. Then heights tend to rise as the period progresses, though some level of troughing will be maintained. Meanwhile overall ridging builds across the eastern Pacific and into northwestern North America, but with increasing chances for it to get disrupted by a shortwave around Sunday. Model guidance shows relatively good agreement with this overall pattern. However, plenty of differences remain in the details of individual shortwaves and surface low pressure systems, especially as they potentially approach southern AK. Today's guidance is generally stronger with the aforementioned shortwave quickly moving across southern Alaska/Gulf/northern Pacific over the weekend, but with timing differences--the 12Z ECMWF and GFS were clustered east of the 12Z CMC and 06Z GFS--so tried to take a middle ground approach. This also maintains an occluded low pressure system in the Gulf of Alaska longer than the previous forecast. While some surface lows could be somewhat strong late week, but there is considerable run to run and model to model variability in their placement and strength. Guidance is most agreeable for a massive and deep (likely in the 960 mb range) low centered south of the Aleutians Sunday-Monday. However there are still considerable differences in the placement of the low, with generally the deterministic models north with its center compared to the ensemble means. This could certainly affect impacts of the low over the Aleutians, but given the breadth of the low the Aleutians could still be impacted even if the low is well south. All considered, the WPC forecast began with a blend of the deterministic GFS/ECMWF/CMC, with the blending process smoothing out some of the particulars of the individual models. Then gradually phased in the GEFS and ECMWF ensemble mean guidance to the majority by the end of the period. ...Weather/Hazard Highlights... Southwesterly flow between the Bering Sea upper low/trough and the East Pacific/far western Canada ridge will support wet weather over southern Alaska continuing into the weekend. Individual surface lows will periodically help to focus heavier episodes of rain in low/coastal areas and heavy snow in higher elevations. Highest totals are likely to be from the southeastern coast through the Panhandle, particularly through Thursday, while amounts over locations farther west will depend more on exact storm tracks with the series of low pressure systems. Some snow may extend farther north into the mainland especially mid-late week. Each storm could also produce brisk to strong winds and rough seas between the Aleutians/Alaska Peninsula and the Panhandle, with the most likely period of high winds next Sunday-Monday in the Aleutians if the current forecast storm track occurs. Below normal temperatures are expected for the far western mainland through the period underneath the trough. Near to above average temperatures are forecast elsewhere, with the largest above average anomalies across the southeastern mainland. Tate 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