Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 758 PM EDT Tue May 23 2023 Valid 12Z Sat May 27 2023 - 12Z Wed May 31 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. There still remains some uncertainty within the latest guidance on the evolution. 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... The latest run of guidance began with a little better clustering initially than the previous for the evolution of the initial southern coast into northeastern Pacific upper trough, likely containing an embedded low near or a little southeast of the Kenai Peninsula as of early Friday. The guidance has also been persistent with a faster trend for the Bering Sea system tracking eastward into the Gulf of Alaska, particularly after Saturday, as well as a modest southward trend. As the extended period progresses, the guidance is continues to suggest ridging in a west-east orientation tries to re-establish across northern portions of the Mainland. To help maintain continuity the preferred blend continued to lean slightly heavier on the ECWMF/GEFS/EC ensemble means but also included small percentages of the GFS and CMC. With confidence in specifics declining further after mid-period, the blend increased ensemble mean weight to 55 percent with the remainder composed of the operational runs to enhance detail versus the means where possible. ...Sensible Weather and Potential Hazards... Precipitation is expected to be ongoing across the southern coast and Panhandle in association with the initial southern coast/northeastern Pacific upper trough and associated surface reflection. Rainfall intensity will be decreasing through the day on Friday 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/Rausch 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