Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 552 PM EST Sat Jan 09 2021 Valid 12Z Wed Jan 13 2021 - 12Z Sun Jan 17 2021 ...Active Pattern Continues Across Gulf of Alaska Next Week... ...Guidance/Uncertainty Assessment... A pair of shortwave troughs and/or closed lows are forecast over the Gulf of Alaska during the period with an increasingly amplified upper level pattern. The first system has reasonable agreement on day 4 but the 12Z GFS quickly falls out of favor in the preferred blend as it becomes too amplified and fast with the upper level energy. This becomes even more apparent for the second system, as the GFS takes it well east/south compared to the other deterministic guidance. As such, the WPC blend incorporated little of the 12Z GFS and instead focused on the better agreement seen in the 12Z ECMWF/CMC. By day 7-8, with the typical model biases coming into play, the blend used more of the ECENS/GEFS. ...Weather/Hazards Highlights... A pair of storm systems are forecast to impact the southern/southeast coasts next week, the first should be ongoing/weakening on day 4 with low pressure over the eastern Aleutians. A brief lull with some ridging in place for day 5 will be quickly followed by another deepening low pressure lifting toward the southern coast and is likely to bring significant precipitation, high winds, and significant waves. For much of the interior regions, above normal temperatures and below normal precipitation is expected. Taylor 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 across portions of the Alaska Panhandle and mainland Alaska, Mon, 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