Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 507 PM EST Thu Jan 07 2021 Valid 12Z Mon Jan 11 2021 - 12Z Fri Jan 15 2021 ...Deep lows offer heavy precipitation and wind/waves threats from the Gulf of Alaska to Southern/Southeast Alaska Sun-Mon... ...Guidance/Uncertainty Assessment... The WPC Alaskan product suite was derived from a composite of reasonably clustered guidance from the 12 UTC GFS/ECMWF/UKMET/Canadian and the 19 UTC National Blend of Models (NBM) Monday before rapid transition to more compatible GEFS/ECMWF ensemble means and the NBM Tue-next Fri. This Alaskan office collaborated plan seems consistent with quick growing forecast spread and avoids ugly embedded system run to run continuity issues in the models. Offshore lows were manually deepened in WPC surface progs to be more consistent with favorable upper support predictability and to counter weakening effects inherent from the blending process. ...Weather/Hazards Highlights... There remains a well defined guidance signal favoring closed upper low/trough and deep cyclogenesis emergence into the Gulf of Alaska Sun/Mon whose enhanced onshore moisture fetch and circulation is expected to fuel a threat of heavy precipitation and high winds/waves from the Gulf into southern and southeast Alaska. Subsequent energies and system interactions/developments are all over the place in deterministic guidance, albeit in a overall favorable larger scale pattern in guidance. Accordingly, expect an unsettled pattern with multiple lows to persist next week over the Gulf, with main onshore effect focus into southern/southeast Alaska. Significant system details may not be revealed until shorter time frames, perhaps 3-4 days in advance. The ensemble mean based WPC surface progs hint at but do not explicitly depict these less predictable lows around a main centered low position. Given potential intensity of these systems, there may be strong winds and hazardous marine conditions. This pattern should also favor some much above normal temperatures into the Interior next week. Schichtel Additional 3-7 Day Hazard information can be found on the WPC medium range hazards chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php Hazards: - Heavy precipitation for southern Alaska and the Alaska Panhandle, Sun-Mon, Jan 10-Jan 11. - High winds for southern Alaska, Sun-Mon, Jan 10-Jan 11. 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