Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 506 PM EDT Sun Oct 31 2021 Valid 12Z Thu Nov 04 2021 - 12Z Mon Nov 08 2021 ...Overview and Model Guidance... A pattern with potent offshore storms will continue to affect portions of Alaska for the coming week. The flow will feature several potent Bering Sea and Gulf of Alaskan lows rotating within energetic/closed mean upper troughs over these areas and around the periphery of an amplified western Canada to Interior mean upper ridge. Guidance continuity and variance with embedded features remains less than stellar throughout medium range time scales, but a blend of best clustered guidance from the 12 UTC GFS/ECMWF/Canadian/UKMET does offer a seemingly reasonable solution that despite many messy smaller scale system differences maintains decent larger scale WPC product continuity day 4 into day 5 (Thursday into Friday). Forecast spread rapidly increases after that and WPC guidance quickly turns to the more smoothed but more compatible GEFS/ECMWF ensemble means later Friday into days 6-8. ...Weather/Hazard Highlights... A lead extratropical low partially associated with recent western Pacific Typhoon Malou will lift to the northern Gulf of Alaska Wednesday into Thursday. This offers some threat for maritime interests and inland as heavy precipitation works from southeast through southern Alaska and the AKpen/Kodiak Island. There is now an increasing guidance signal that another low linked to Malou may also lift into the Gulf of Alaska or western Canada Friday, perhaps into Saturday to offer a less certain focus for heavy precipitation. Meanwhile, additional storm systems will also into this period work from the Bering Sea and combine with energies lifting on the western periphery of an amplified Interior upper ridge position to spread periods of enhanced precipitation into western Alaska. In this pattern, the central and eastern Interior through the North Slope should enjoy much above normal readings this week, with many locals more than 20 degrees above normal. Deep energy digging underneath into the Gulf of Alaska late week through next weekend into early next week may also present a favorable environment for storm genesis with amplified/closed upper trough development to present a multi-day maritime and southern and southeastern coastal tier threat. However, particular deep storm depiction at these longer time frames, as now most evident in the 12 UTC GFS, is quite uncertain given run to run guidance variance and limited ensemble clustering. 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