Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 435 PM EDT Sat Sep 25 2021 Valid 12Z Wed Sep 29 2021 - 12Z Sun Oct 03 2021 ...Three Major Storms for Alaska... ...Guidance/Predictability Assessment and Pattern/Hazard Highlights... The models continue to provide a reasonable handling of the medium range pattern including the overall development of major storms next week, bolstering forecast confidence. I again suggest a blend of the 12 UTC GFS/ECMWF/UKMET/Canadian days 4-6 (Wed-Fri) along with the 19 UTC National Blend of Models and would keep the well clustered GFS/ECMWF in the mix along with the best compatible ECMWF ensemble mean for days 7/8 (next weekend). The ECMWF ensemble mean is slightly more amplified upstream than the 12 UTC GEFS at these longer time frames and that seems more reasonable considering expected approach toward the SW Bering Sea of the deep extratropical low associated with current west Pacific Typhoon Mindulle. WPC product continuity was well maintained in this manner along with some manual surface system modifications to ensure sufficient offshore storm depth/intensity consistent with a highly supportive and amplified upper flow evolution as a series of powerful closed lows/troughs work through the Bering Sea and into the Gulf of Alaska. A deep storm system through midweek will bring a threat of high winds/waves across the Gulf of Alaska, allowing a southwesterly push of moisture to funnel especially into the Panhandle where rainfall amounts may be locally heavy in the valleys (and snow at the higher elevations). The next dangerous storm system out of the northern Bering will robustly dig to bring high winds/waves along with an enhanced rain/snow to western then southwestern areas of the mainland. Into later next week as the system slams into the highly unsettled Gulf, another round of potentially heavy rain/snow are expected for the Panhandle and coastal areas of south-central Alaska. Temperatures will overall generally be below normal for the period due to the continued troughing over much of the state. Farther upstream, powerhouse typhoon Mindulle will start to recurve into the westerlies from the south of Japan by midweek. After that, the ensemble consensus takes the system to the northeast into/toward the trough to its north/northeast. A deep extratropical low associated with Mindulle is slated to track toward the southwest Bering Sea next weekend as a maritime and Aleutians heavy seas/wind/rainfall threat. 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