Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 618 PM EST Wed Feb 02 2022 Valid 12Z Sun Feb 06 2022 - 12Z Thu Feb 10 2022 ...Overview... An upper-level trough axis will extend through northwestern Alaska through next week, stretching westward from an upper low over northern Canada and possibly serving to connect an upper low initially spinning west of the Aleutians Sunday and drifting east. Farther south, expect a more progressive pattern of shortwaves and surface low pressures from the Aleutians and southwestern mainland to the Panhandle. These features will spread periods of precipitation into the southern part of the state and possibly northward into central and northern parts of the mainland by the middle of next week. Precipitation could be heavy particularly from the Kenai Peninsula into the Panhandle. ...Guidance/Predictability Assessment... Model guidance is in fairly good agreement with the trough axis extending from northeast to southwest through much of the mainland, while the southeastern part of the state sees general ridging disrupted by shortwave energy especially early in the week. However, ample differences in the details remain, including the possibility for an upper low to close off within the troughing pattern. Most recent guidance does close off a low but the timing of its development and the placement differ considerably. The ECMWF deterministic run and the ensemble mean are showing solutions farther east with the closed low compared to other guidance, with the low/trough axis remaining over western Alaska rather than drifting into the Bering Sea by around Wednesday. At this point attempted to take a middle ground position with the trough axis (and with the temperature forecasts that are similarly affected) since both the eastern EC and the western GFS/CMC solutions seemed reasonable. In terms of features farther south, an initial surface low near the Kenai Peninsula Sunday has good agreement among guidance, while models also agree upon a large surface low/frontal system tracking south of the Aleutians through the early part of the week, but then end up diverging with its track and with possibly another surface low upstream. Thus the WPC forecast utilized a multi-model blend of deterministic guidance (12Z ECMWF, CMC, and UKMET at 06Z/12Z GFS) early in the period when there was better agreement, and gradually incorporated more GEFS/EC ensemble means to about 60%Âby day 8. ...Weather/Hazard Highlights... The overall pattern with troughing over western Alaska will promote deep layer southwesterly flow, bringing moisture to especially southern Alaska through the period, while rounds of surface low pressure will help to focus the moisture and produce precipitation. Multiple rounds of rain in the low/coastal areas and heavy, wet snow in the higher elevations should span from the Alaska Peninsula into the Southeast and Panhandle through much of next week. There is also a chance for gusty winds and rough seas with these systems in the vicinity of the Aleutians and Alaska Peninsula to Southcentral Alaska and the Panhandle. Snow may become more likely farther north into much of the mainland by the middle of next week as a surface low is currently expected to track into the southwestern mainland. Temperature readings during the period will be generally near to below normal across much of the state through the early part of the week but moderating by Wednesday and Thursday, while warmer than average temperatures are likely in southeastern Alaska and the Panhandle underneath overall ridging. Tate Hazards: - Heavy precipitation across portions of the Alaska Panhandle into southern coastal Alaska, Sat-Wed, Feb 5-Feb 9. - Heavy precipitation across portions of southern coastal Alaska, Tue-Wed, Feb 8-Feb 9. 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