Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 744 PM EDT Wed May 24 2023 Valid 12Z Sun May 28 2023 - 12Z Thu Jun 01 2023 ...Overview... The large scale pattern over the next week plus should be conducive for enhanced rainfall/high elevation snow along and near the southern coast into the Panhandle with an initial southern coast into northeastern Pacific upper trough (likely containing an embedded low) and then steady progression of a Bering Sea system into the Gulf of Alaska. With increased cloudiness and precipitation these areas may also be a few degrees cooler than seasonal average for late May/early June. Solutions have been quite varied over recent days regarding flow aloft farther north over the mainland and Arctic, with individual solutions varying among a modest north-south trough/weakness, east-west ridging, or a col region depending on the day. ...Guidance Evaluation/Preferences... Clustering has improved with the latest run of model guidance through much of the extended period, but particularly the first half. The last couple of forecast cycles leaned heavily on the ECWMF and the GEFS/EC ensemble means since they were the most clustered guidance, however the other global guidance have merged closer to the ECWMF track. All solutions have trended a little faster/east with systems moving from the Bering to the Gulf of Alaska and the overall mean trough that sets up over the Gulf. There continues to be a signal for some weak ridging for the portions of the Mainland. The preferred WPC blend comprised of a multi-model blend (slightly heavier on the ECWMF), the NBM and increasing weights of the GEFS/EC ensemble means for the later periods. ...Sensible Weather and Potential Hazards... Much of the Southeast and southern coast will have ongoing rain, although the rainfall intensity will be decreasing through the day as the upper system opens. Meanwhile, the system over the Bering Sea (with a surrounding area of brisk winds late this week) will spread precipitation across the eastern Aleutians/Alaska Peninsula late this week, followed by potential enhancement over some locations along the eastern Alaska Peninsula and points eastward during the weekend with a triple point wave that may track near Kodiak Island before heading into the Gulf of Alaska. Persistence of rain/higher elevation snow during the first part of next week will be sensitive to the exact track of this wave. Some areas of precipitation will be possible over other parts of the mainland late week into the weekend due to the energy ejecting from the initial southern coast/northeastern Pacific system. Then coverage and amounts over the central/northern mainland will depend in part on uncertain details of flow aloft. Over the next week most of the state will likely have below normal high temperatures, with coolest anomalies likely to be across southern areas. The far northwestern corner of the mainland may have the best chance for above normal highs late this week into the weekend. Anomalies should be warmer for low temperatures, with a mix of readings above or below climatology. Along with the precipitation forecast, uncertainty with details of flow aloft also tempers confidence in temperatures over the northern half of the mainland by the latter half of the period. Campbell No significant hazards are expected over Alaska during this forecast period. 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