Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 608 PM EDT Sat Jul 15 2023 Valid 12Z Wed Jul 19 2023 - 12Z Sun Jul 23 2023 ...Increasingly wet pattern mid-later next week for especially western and southeast Alaska... ...Guidance Evaluation/Preferences and Predictability Assessment... Forecast clustering has improved for Wednesday into Thursday as per a more progressive flow trend over the higher latitudes into Alaska. This is a signifcant change from yesterday's guidance, but perhaps guidance that has been sensitive to initial conditions recently has finally stabilized given the forecast is working toward usually more predictable short range time scales. This was the case at high latitudes a few days ago as well and the trend was your friend. A composite of the 12 UTC GFS/ECMWF/UKMET/CMC seems reasonable then before transitioning to a blend of the compatible GEFS/NAEFS/ECMWF ensemble means for the rest of next week amid growing system uncertainties. However, run to run continuity has recently been better over the southern half of the state and the stormy Gulf of Alaska. Accordingly, plan to again apply manual adjustments there to offset the blending process to ensure sufficient low pressure system depth and wind speeds given favorable upper support in most guidance. ...Weather/Hazards Highlights... The carving out of an amplified and slow moving closed upper trough and deepening surface based low over the Gulf of Alaska to the east of an anomalously amplified upper ridge will present a protracted maritime threat next week. Meanwhile, easterly waves rotating overtop mainly from Southeast Alaska to eastern Southcentral/Alaska Range and southeast Interior will support uncertainly timed daily bouts of mainly light to moderate rains across the broad region next week, but perhaps especially into locally favored terrain of the Southeast and the eastern Alaska Range into next midweek and again by next weekend depending on closer proximity of the closed low offshore over the Gulf of Alaska. Meanwhile, expect increasing and more widespread rains and unsettled weather will work into western and southwestern Alaska/Alaska Peninsula and more modestly across the Interior mid-later next week as there is a growing guidance signal to support the eastward approach of a modestly deep but potentially moist Bering Sea system set to round through the northern periphery of the aforementioned upper ridge. This system is now reaching the region more progressively. 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