Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 644 PM EST Sat Feb 05 2022 Valid 12Z Wed Feb 09 2022 - 12Z Sun Feb 13 2022 ...Overview... The pattern over Alaska during the latter half of next week into the weekend will feature an elongated upper trough over parts of the mainland, which is likely to have an embedded upper low over the Bering Sea near the western mainland Wednesday-Thursday of next week. Meanwhile overall ridging builds across the eastern Pacific and into northwestern North America. This pattern will allow for a surface low pressure system to track into south-central and southeastern Alaska around midweek, and a series of additional lows are likely to progress south of the state through the weekend. These will spread precipitation especially into southern Alaska, with some snow farther north in the mainland particularly Wednesday and Thursday. ...Guidance/Predictability Assessment... The guidance consensus since yesterday has shifted somewhat with a surface low position 12Z Wednesday. Yesterday's forecast showed the low going into the southwest mainland but is now closer to Kodiak Island on the southern side of the Alaska Peninsula. The ECMWF and EC mean are a bit east with this feature compared to the GFS/CMC, given lingering differences in the Bering Sea upper low and the shortwave energy passing through on the southern side, though the EC is supported by the UKMET. Leaned a bit toward the western position shown by the GFS/CMC suite. Guidance is becoming somewhat more agreeable in converging on a middle ground position for the Bering upper low at least initially on Wednesday, not as far west as previous GFS runs and not as far east as previous ECMWF runs. The position of the NAEFS mean worked well for this feature. That upper low drifts northeast and likely weakens for the latter part of the week, but still with notable timing differences when it lifts out and how much energy is left behind. Farther south, a storm track south of the Aleutians will take rounds of troughing and surface lows through the northern Pacific and possibly near the Aleutians/southern coastal Alaska. Some of these surface lows could be potent, but there is considerable run to run and model to model variability in their placement and strength through the end of the week. In fact the best signal for a deep storm system (deterministic models show the low in the 950s) is not until next Sunday, when guidance agrees better on a position well south of the Aleutians but still may be large enough to affect the region with strong winds. Thus the WPC forecast began with a blend of mainly deterministic models but including the NAEFS mean even at the beginning, and increased the proportion of ensemble means to 50 percent by day 6 and beyond given the large differences in the details among deterministic guidance. ...Weather/Hazard Highlights... Southwesterly flow between the Bering Sea upper low/trough and the East Pacific/far western Canada ridge will support wet weather over southern Alaska during most of next week. Individual surface lows will periodically help to focus heavier episodes of rain in low/coastal areas and heavy snow in higher elevations. Highest totals are likely to be from the southeastern coast through the Panhandle, particularly Wednesday into Thursday, while amounts over locations farther west will depend more on exact storm tracks with the series of low pressure systems. Some snow may extend farther north into the mainland especially mid-late week. Each storm could also produce brisk to strong winds and rough seas between the Aleutians/Alaska Peninsula and the Panhandle, with the most likely period of high winds next Sunday in the Aleutians if the current forecast storm track occurs. Below normal temperatures are likely across northern and western parts of the state around midweek given the upper low in the vicinity, which should gradually moderate by the end of the week and confine the below average temperatures to the far western mainland. Near to above average temperatures are forecast elsewhere, with the largest mild anomalies across the southeastern mainland. 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