Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 721 PM EDT Sat Jun 03 2023 Valid 12Z Wed Jun 07 2023 - 12Z Sun Jun 11 2023 ...A stalled deep layer low will continue bringing rain to the Alaska Peninsula/Southcentral mid-late next week, with precipitation chances spreading north with time... ...Overview/Guidance Evaluation/Preferences... A consolidating upper low and its associated surface low reflection slowly positioning itself over the eastern Aleutians/Alaska Peninsula will be the main weather feature going into next week/weekend across the Alaska region. With such a blocky pattern, there is relatively good model agreement and higher confidence in the bigger picture details. By Wednesday/Day 4 the low will likely settle just north of the Aleutians with some drift southeastward with time. Recent model guidance agrees on this quite well through at least Friday/Day 6, though GFS/GEFS runs eventually show the low tracking farther east than the non-NCEP guidance next weekend, and given the blocky pattern, a slower track holding the low west may be more likely. GFS runs also show some additional rounds of energy in the northern Pacific well south of the state (but potentially affecting the main low's position) that are rather low confidence at this point. A quick bout of upper ridging may remain across eastern to northern parts of Alaska Day 4/Wednesday before it pushes east into western Canada. This ridge exiting will allow for some lower pressures and perhaps a frontal system or two to affect the Interior. Overall a multi-model deterministic blend of the 12Z GFS/ECMWF/UKMET/CMC was able to be used for the WPC forecast through Days 4-5 with slowly increasing amounts of the GEFS and EC ensemble mean guidance as the period progressed, while reducing the GFS component (and the UKMET of course). ...Sensible Weather and Potential Hazards... The heaviest precipitation amounts associated with the stacked low may take place early next week in the short range period when moisture anomalies are highest, perhaps channeling moisture from what was Mawar in the western Pacific. But some precipitation is likely to last for several days over the Alaska Peninsula to Southcentral Alaska regions all the way into next weekend as the low stalls/slowly meanders. Mainly rain is likely, though some precipitation could be snow in the highest elevations. Rain amounts over time could accumulate to several inches next week for parts of the Alaska Peninsula and Southcentral Alaska. Precipitation chances are forecast to increase farther north across Interior Alaska for the latter part of next week into next weekend, with some widespread moderate rain amounts possible. Warmer than normal temperatures are possible for areas north of the Alaska Range on Wednesday underneath the brief upper ridge, with lows in the 50s and highs in the 70s for the lower elevations of the Interior. Wednesday and perhaps Thursday may be warmer than normal for parts of Southeast Alaska as well before a cooler trend. The upper low and the coincident rain and cloudiness chances should keep high temperatures down below normal along the southern coastal regions. Then as some of that moisture and rain chances spread northward, temperatures at least in terms of highs should moderate closer to normal or below normal for much of the Mainland late week into the weekend. Tate 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