Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 743 PM EDT Fri Mar 31 2023 Valid 12Z Tue Apr 04 2023 - 12Z Sat Apr 08 2023 ...Overview with Guidance Evaluation/Predictability Assessment and Weather/Hazard Highlights... The medium range forecast period for Alaska will begin on Tuesday with an occluded cyclone center ready to make landfall over southwestern Alaska while a triple-point low moves into the Gulf of Alaska. Since a couple of days ago, models and ensembles have settled into this current forecast regime for this area, allowing the triple-point low to move through the upper ridge and lingering the low over the Gulf of Alaska through the middle of next week. There is further convergence of the model solutions toward this regime today. With this regime in place, the triple-point low is forecast to linger over the Gulf of Alaska into late next week as the next cold upper trough/low from eastern Russia moves across the Bering Sea and begins to interact/merge with the lingering low over the Gulf by Saturday. Models and ensembles show excellent agreement on this interaction/merger. The exception was the 00Z ECMWF which allows robust cyclogenesis to occur south of the Alaska Peninsula. This scenario is supported neither by the 00Z nor the 12Z EC ensemble means. The proximity of this system to land means that a higher chance of precipitation will overspread the southern coastline and down into the Panhandle starting next Tuesday. These precipitation chances are forecast to linger along the southern periphery of Alaska going into next weekend. It appears that the precipitation amounts are maximized over the Panhandle late next week with the ECMWF having the most robust solution, but we are not expecting to see them reach excessive levels at this point. In addition, the system will likely bring a period snow across southwestern Alaska Tuesday and Wednesday. Farther upstream, additional smaller scale low pressure systems moving across the North Pacific will continue to introduce uncertainty to the pattern affecting the Aleutians in the longer range forecasts although model agreements appear excellent at this point in time. Meanwhile, northern Alaska will start out milder than normal but well below hazards levels. Temperatures for the rest of mainland Alaska will average close to normal. There is some spread seen in the deterministic solutions regarding a lingering upper low over the Arctic Ocean to the north of Alaska. Ensemble means are in good agreement regarding this feature through Day 8. The WPC Alaskan forecast package begins with 40% from the 12Z EC and EC mean, 40% from the 12Z GFS and GEFS, and 20% CMC and CMC mean, transitioning to mostly a blend of the ensemble means, with smaller contributions from the deterministic solutions through Day 8. Kong Hazards: - No significant hazards are expected over Alaska during this forecast period. 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