Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 642 PM EST Sun Jan 3 2021 Valid 12Z Thu Jan 7 2021 - 12Z Mon Jan 11 2021 ...Overview and Guidance/Uncertainty Assessment... A rather stormy weather pattern appears likely across the Aleutians and Gulf of Alaska region for the end of the week and extending into early next week. A weakening storm system that will initially be over the northern Gulf region is forecast to be replaced by an intensifying storm that lifts northeastward from the North Pacific by this weekend. Meanwhile, another strong storm crossing the Aleutians on Saturday is expected to merge with the Gulf system by Sunday and become a large and broad low pressure gyre by the end of the forecast period. Perhaps surprisingly is a greater level of model spread early in the period regarding shortwave perturbations around the weakening low, and once the pattern becomes more amplified and defined, the deterministic CMC/EC/GFS are in above average agreement for the Day 6-8 time period, and this justified a general blend of those models, along with some of the ensemble means, for this time period as a starting point in the forecast process. ...Weather/Hazards Highlights... The multiple northeastern Pacific/Gulf systems should bring a multi-day period of moderate to occasionally heavy precipitation to areas along the southern coast and Panhandle region. The best confidence in highest five-day totals extends from near the Kenai Peninsula to the southeast Panhandle. Locations farther west will be more sensitive to the exact track of low pressure centers. Given the predicted intensity of these systems, there will likely be strong winds and hazardous marine conditions. Meanwhile, strengthening winds and increasing precipitation should reach the western Aleutians around late Friday and then extend across the rest of the islands during the weekend as the associated storm system progresses eastward. The upper level pattern will favor the establishment of generally above normal temperatures across most areas during the medium range period. Locations over the northwestern mainland will likely be the last to see above normal readings. The above normal anomalies for low temps should generally be greater than those for highs. Hamrick Additional 3-7 Day Hazard information can be found on the WPC medium range hazards 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