Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 643 PM EST Sat Mar 05 2022 Valid 12Z Wed Mar 09 2022 - 12Z Sun Mar 13 2022 ...Overview... A persistent upper high atop eastern Russia and the Chukchi Sea will help promote above normal temperatures particularly for northern and eastern parts of Alaska during the period (next Wednesday to Sunday). Mainland Alaska will generally be in a col pattern between this feature, rounds of upper troughing/lows over the Aleutians, ridging over the East Pacific that should get shunted eastward by late week, and periods of troughing in the northeastern part of the state. This should lead to unsettled weather particularly over the Aleutians, with some precipitation spreading east in the southern half of the mainland and Panhandle. ...Guidance/Predictability Assessment... Recent model guidance is generally most agreeable with the upper high to the northwest of Alaska, with more variability among models to the south and east. Upper lows and energy are forecast to meander across the Aleutians and the surrounding waters, supporting development of likely several surface lows during the period. The details of these smaller scale features within this broader troughing pattern are quite uncertain and will likely take a few more days for models to converge properly. Regardless, models generally show some of this energy spilling eastward to shunt the East Pacific ridge east into North America by late week, though with some timing differences. Another uncertain part of the forecast is how much troughing/energy can influence eastern Alaska at times, to the east of the blocking upper high. In general the 12Z guidance suite indicated stronger energy there compared to previous cycles (with the ECMWF the strongest) by late next week, which led to a more stationary high compared to the previous forecast that had the high migrating farther into the Chukchi Sea. There is low confidence with these high latitude features though. Given the somewhat agreeable overall pattern but the ample differences in the details, the WPC forecast was based on a blend of the ECMWF/GFS/UKMET early in the period, transitioning to a ECMWF/ECens mean/GFS/GEFS mean by the latter part of next week into the weekend. The CMC was excluded this time given some differences from consensus particularly in the northern Pacific. ...Weather/Hazard Highlights... A series of lows (and triple point lows) will rotate through and reform near the Aleutians through the extended period. This will keep much of this part of the region unsettled, with periods of enhanced rains/winds for the Aleutians. Modest precipitation is expected to spread eastward into southern parts of the mainland and then the Panhandle for the latter part of the week as ridging shifts away from the state. The heaviest amounts are forecast along the coast, but some snow should spread farther north in the mainland as well. Milder temperatures than normal are forecast for much of the mainland through at least midweek, particularly in terms of low temperatures that should be 15-30F above average, while highs 10-20F above normal are expected especially for northern and western parts of the state. Temperatures should moderate closer to normal by next weekend but remain above average for western Alaska, while the Panhandle and eastern mainland are cooler. 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