Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 623 PM EDT Sun Jun 02 2024 Valid 12Z Thu Jun 06 2024 - 12Z Mon Jun 10 2024 ...Guidance Evaluation and Preferences... Prefer a composite of reasonably clustered 12 UTC GFS/ECMWF/UKMET models and the 12 UTC GEFS mean in a pattern with near average predictability. Increased blend weighting of the best compatible 12 UTC GEFS mean by next weekend amid growing forecast spread. This solution now lifts a deeper storm system northward into the Gulf of Alaska later this week. This seems reasonable considering recent flow history within a well defined and energetic upper flow train already set-up from east Asia and the mid-latitudes of the Pacific toward Alaska as now shown in water vapor satellite loops. These types of trends often show a positive signal within the more predictable first half of medium range time scales, especially when sensitive data initialization data is over land for upstream activity which is at least partially the case in this scenario. The 00 UTC ECMWF ensembles had less support for this solution compared to most other guidance, but the latest 12 UTC ECMWF ensembles version is trending a bit more favorably. ...Weather/Hazards Highlights... A leading and initially quite wet/moist surface low/system will steadily lose influence into Thursday while rotating back across the northern Gulf of Alaska as northern stream upper low/trough energies dig down through the Bering Sea and eastern Aleutians. Expect lingering light to moderate rains over southern coastal areas of the state. Easterly wrapping flow and impulses offer an additional threat of precipitation inland across SouthCentral/Alaska Range and into the Interior through late week followed with continued building of warming upper ridging over the Mainland. To the south, now expect a deepened storm system will lift from the central Pacific to the Gulf of Alaska late week into next weekend as an upstream deepened system now exiting eastern Asia ejects earnestly across the north Pacific to the south of the Aleutians and toward the Gulf of Alaska within a dynamic wave train. The combination of these systems offer multi-day high wind/wave and heavy rain threats for Gulf maritime interests and from the Aleutians through SouthCentral to monitor heading into next weekend. Schichtel 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