Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 640 PM EST Sun Jan 30 2022 Valid 12Z Thu Feb 03 2022 - 12Z Mon Feb 07 2022 ...Overview... The large scale pattern over Alaska will be fairly stagnant late this week into early next week, with a col generally in place over Alaska, separating deep layer low pressure west of the Aleutians and an upper high retreating well northwest of the state while an upper low slowly drifts east over far northern Canada--these features create some semblance of an omega block. The upper level gyre just west of the Aleutians will produce shortwaves pivoting around it, sending them eastward along the southern part of the state. These shortwaves should produce rounds of surface low pressure tracking across southern coastal Alaska along with multiple rounds of precipitation, with the heaviest rain/snow from the Kenai Peninsula to the southeast Panhandle. ...Guidance/Uncertainty Assessment... The 12Z suite of model guidance remains in fair agreement with the overall pattern described above, but with substantial timing and track differences in smaller scale features such as the individual shortwaves and associated surface lows tracking across the Bering Sea, northern Pacific, and the Gulf of Alaska. Additionally, model differences were noted with the timing of the high northwest of the state retreating north with time. Per coordination with the Alaska Weather Forecast Offices, models tend to be too fast to erode a high/blocking pattern in this position near Siberia, so favored holding onto the ridge axis into northwest Alaska through the latter part of the week before a trough axis could dip into northern Alaska by early next week. With deterministic guidance generally quicker to erode this ridge than preferred, today's WPC medium range forecast was based on a blend of half ensemble mean guidance and half deterministic models (06Z/12Z GFS and 12Z ECMWF) early in the period, increasing to about 70 percent ensemble means by the end. This also worked given the uncertainty in individual models with the shortwave features and surface lows, though some deepening of the lows along coastal southern Alaska was drawn manually to maintain some strength of those features. ...Weather/Hazard Highlights... Several low pressure/frontal systems tracking near coastal southern Alaska will draw moisture into the southern part of the state and provide forcing for rounds of precipitation across the Alaska Peninsula, Southcentral Alaska, and into the Panhandle late this week into early next week. Gusty winds are also possible from the Aleutians eastward across the coastal Alaska. Then farther north, arctic high pressure will be in place across northern Alaska, keeping the Interior dry through late week. Some snow showers over the northern mainland may be possible early next week as the high retreats. Below normal temperatures across much of the Interior will gradually retreat to the North Slope by early next week, while generally above average temperatures are forecast for southern Alaska. 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