Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 659 PM EST Sat Dec 10 2022 Valid 12Z Wed Dec 14 2022 - 12Z Sun Dec 18 2022 ...Synoptic Overview... The overall weather pattern across the Alaska domain is expected to remain rather active for the middle to end of the week as a strong low pressure system lifts northward across the eastern Aleutians and the Alaska Peninsula, with deep onshore flow and heavy precipitation for southern coastal areas. Another system may enter the Bering Sea region by next weekend, but future forecasts will refine this potential further. Meanwhile, an upper level ridge will likely build in across mainland Alaska going into next weekend, with some potential for an omega block pattern trying to develop. ...Guidance/Predictability Assessment and Preferences... The 12Z model guidance suite has come into a little better agreement for the middle of the week. However, the 18Z GFS is to the southeast of the model consensus with the closed low affecting the southern portion of the state, and would have a greater impact on the southeast Panhandle if this solution verifies. There is a decent model signal for a significant storm system emerging from eastern Siberia late next week into Saturday, although big timing and latitudinal differences are apparent. The fronts/pressures forecast was primarily derived from a nearly deterministic 12Z model blend, and slightly increasing the proportion of the EC/GEFS means with each successive day, while still maintaining some previous WPC continuity. ...Weather/Hazards Highlights... This pattern should lead to increasingly milder conditions across much of the Interior as Pacific moisture advects northward across the state. The southwestern portion of the mainland should have the greatest expanse of above normal temperatures as onshore flow persists for much of the forecast period. The strong low pressure system near the Alaska Peninsula and northern Gulf Thursday/Friday will likely lead to an atmospheric river event with extremely heavy mountain snow for the southern mountains and several inches of rain near the coast. Hamrick 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