Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 751 PM EDT Wed Apr 20 2022 Valid 12Z Sun Apr 24 2022 - 12Z Thu Apr 28 2022 ...Guidance/Predictability Assessment... The extended range period over Alaska features a weakening surface low over the Gulf while a couple of systems move into the Bering Sea and near the Aleutians. With the Gulf low, the latest models continue to show some timing/placement differences, but a general model blend seems to serve as a good starting point. Later in the period, there is question on how quickly the low exits into western Canada, but there is some general consensus that low pressure in some form should meander in the Gulf as another system approaches upstream. Meanwhile, a deep surface low just south of Kamchatka on Sunday/Day 4 will drift very slowly eastward towards the western Bering, but may eventually weaken early next week as another system to its south moves in. By day 6, some larger problems begin to arise in the evolution of a shortwave rounding the base of broader troughing in the Bering Sea and what eventually becomes a surface low south of the Alaska Peninsula by day 8. The GFS is a little weaker and faster than the ECMWF and brings a surface low along the Aleutians around day 7, while the 12z ECMWF is much sharper with the wave and spins up a surface low which moves well south of the Aleutians. The 12z CMC track is also south of the Aleutians but significantly faster than the ECMWF and GFS and was not included in the blend for the second half of the period. The ensemble means support something a little slower anyways, with a (albeit weaker) placement in between the GFS and ECMWF. Interestingly, by day 8/Wednesday, the low position is pretty reasonably clustered between the GFS, ECMWF, CMC so its more a case of models taking a different evolution, but with a similar end result. The WPC forecast for the second half of the period leans more on the ensemble means to help mitigate these differences. Some of the deterministic GFS and ECMWF were maintained through day 8 through just for a little added system definition. ...Overview Weather/Hazard Highlights... Low pressure in the Gulf will continue some light to locally moderate precipitation across the southern Coast and Panhandle regions, which should wane with time as the low weakens and pushes into western Canada. Mainly light precipitation will progress across the Aleutians associated with a couple of cold fronts through the period and broad troughing shifting east through the Bering. Most of the Mainland should remain dry, save for some scattered activity moving into the western half of the state ahead of the Bering Sea trough. Temperatures across the Mainland should be mostly above normal and trending warmer through the period. Southern regions, from the Aleutians to the Panhandle, should remain near or below average owing to increased clouds and precipitation. Santorelli 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