Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 638 PM EST Sat Feb 11 2023 Valid 12Z Wed Feb 15 2023 - 12Z Sun Feb 19 2023 ...Overview... A closed low is anticipated to track to be near the Bering Strait while another notable closed low tracks across the northern Pacific; likely merging into a single trough leading to much below average temperatures for western Alaska. With a potentially strong low pressure at the surface parts of Alaska with could have high winds and light to moderate precipitation. This appears most likely for the Aleutians but it is becoming more likely for the southern coast as well, dependent on the eventual storm track. Yet another surface/upper low over the Bering Sea later next week could also produce a round of winds and precipitation for the Aleutians and perhaps beyond. ...Model Guidance/Predictability Assessment... The synoptic pattern begins fairly clustered near the surface and upper levels, with the ECWMF and the CMC on the western edge while the GFS and UKMET leading on the eastern periphery. Like several runs of the past few days the solutions diverge beyond day 5. Recent runs of the GFS have signaled a low tracking toward Bristol Bay and then inland. The latest cycle continues that track but even further north into western portions of the Mainland. The other guidance has trended a little further north than previous but not nearly as far north as Bristol Bay. The GEFS mean is better clustered the ECWMF and the EC ensemble means than with is parent solution. Farther upstream, an upper low looks to develop near the Kamchatka Peninsula along with a potentially large and strong surface low. The guidance continues to differ on how far east it will track thus increasing forecast uncertainty for the mid-to-late periods. Regardless energies rounding the low on the southern/eastern side, as well as frontal systems, could affect Alaska, especially the Aleutians. But the details will have to be ironed out in future forecasts. The WPC preferred blend was a compromise of the 12Z ECMWF/CMC/GFS along with increasing weights of the 00Z EC ensemble/12Z GEFS mean. ...Weather/Hazard Highlights... Most of the active weather will focus from the Aleutians to the Southeast through the course of the extended period. Pacific moisture will be directed onshore across the southern Mainland and into the Panhandle as a surface low enters and remains over the Gulf of Alaska, while weakening. Light snow chances across the central mainland are forecast to decrease as well. The weather will become more active by midweek for the south-central and southeast portion of the state as an upper troughing and surface low pressure tracking eastward likely through the northern Pacific. The specifics with this system remains a bit uncertain given the model difference and the amounts and location will be dependent on where it tracks. This system will usher in another round of precipitation for southern Alaska with snow possible for inland locations along with enhanced winds in the Aleutians. Additionally, another round of precipitation and winds are likely to affect the Aleutians as a frontal system stemming from a Bering Sea low comes in, which could spread farther east by the latter half of the week. The upper trough over the western/southern mainland will lead to below normal temperatures where temperatures are forecast to be below normal by 20-30F and perhaps locally lower, while eastern parts of the mainland have a mix of above and below average temperatures. Temperatures should moderate closer to normal across western Alaska by Thursday-Friday. Campbell 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