Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 650 PM EST Sun Jan 07 2024 Valid 12Z Thu Jan 11 2024 - 12Z Mon Jan 15 2024 ...Stormy conditions for the Aleutians and western Alaska... ...Overview... An upper ridge axis stretching from the east Pacific northward into the eastern Interior will cause the main storm track to focus across the Bering Sea and western Alaska through the weekend, leading to an active and windy pattern as multiple low pressure systems move through the region. Another low may also sneak across the Alaska Peninsula to Kodiak Island for some enhanced winds and precipitation there late week. The upper ridge will promote milder than normal temperatures across most areas, with the exception of Southeast Alaska where continental flow ahead of the trough will bring in cold air. The upper ridge may break down early next week. ...Guidance Evaluation/Preferences... Model agreement is good regarding the larger scale ridge setting up and amplifying across eastern parts of the Mainland, but guidance struggles relatively more with the details of shortwaves and surface lows within the mean trough across the Bering/Aleutians. Into Thursday, one shortwave will support a low moving northeast across the eastern Bering while tending to weaken, with some typical variations in the low position and strength. For Thursday-Friday, a surface low from the north Pacific looks to track north toward the Alaska Peninsula/Kodiak Island with fair model agreement as well. A multi-model deterministic blend favoring the GFS and ECMWF could be used for the WPC forecast early in the forecast timeframe. An additional surface low or two should affect the Aleutians into late week. Models have trended toward showing low pressure somewhere near the western Aleutians Thursday initially separate from an upstream potentially stronger surface low approaching by late week. There is some model spread in the positions and interactions of these lows, and with these features now looking to be separate initially, some models like the ECMWF do not show the second low getting as strong as a day ago. However, the central pressure may still be notable and cause strong winds, and wind direction will depend on the exact low track. The CMC seemed to be a slow outlier with the second low. The low is likely to pivot into the eastern Bering over the weekend, but the 12Z GFS may take it northeast too quickly, so included some 06Z GFS in the model blend as well. The WPC forecast transitioned to a blend favoring the ensemble means by half by Day 7 and more Day 8, though maintaining some GFS and ECMWF components. This also worked for the potential breakdown of the ridge as troughing may track east while additional energy pivots west into northeast Alaska from northwestern Canada by early next week. ...Weather/Hazards Highlights... The north Pacific surface low approaching the Alaska Peninsula is likely to focus potentially heavy precipitation across the Alaska Peninsula into Kodiak Island and the southern Kenai Peninsula Thursday-Friday. Gusty winds may affect these areas and southwestern portions of the Mainland, possibly causing blizzard conditions. Some precipitation could track into Southeast by next weekend, but amounts do not look to be as heavy. Initially the eastern Interior should stay dry underneath the upper ridge, before the potential pattern change early next week may allow for some light precipitation there. Surface lows coming near/across the Aleutians could cause high winds and some precipitation. As the period begins Thursday, the western two-thirds of the Mainland will see milder than average temperatures, with the highest anomalies across northern and western portions of the Mainland. Above normal temperatures will expand eastward into the weekend. Meanwhile, Southeast Alaska will see cold/below normal temperatures with northeasterly flow ahead of the ridge axis, but temperatures may moderate closer to normal there by next weekend. With the potential pattern change into early next week, temperatures across the Mainland are likely to cool closer to normal as well. 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