Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 645 PM EDT Thu Aug 08 2024 Valid 12Z Mon Aug 12 2024 - 12Z Fri Aug 16 2024 ...Overview and Guidance Evaluation/Preferences... The latest models offer less than stellar forecast spread during a transitional pattern into early next week as multiple northern stream and Pacific shortwave systems work through the Alaskan domain and vicinity. These models do however show a reasonably similar signal along with ensembles in support of the return of an amplified Bering Sea/Aleutians upper trough and eastern Mainland upper ridge couplet into mid-later next week. Accordingly, prefer a composite of run to run and product continuity consistent 12 UTC GFS/ECMWF/Canadian ensemble means. WPC manual adjustments to this composite by WPC to ensure sufficient offshore low system depth as consistent with individual predictability and as an offset to inherent weakening due to the blending process. ...Weather/Hazards Highlights... Guidance shows quite active and progressive flow into early next week in complex multi-stream flow across all of Alaska as energies work within a expansive mean upper trough position. This will produce widespread unsettled and periodically wet conditions across much of the state, albeit with less protracted local foci amid greater than normal system timing and strength uncertainties. The flow is expected to begin to amplify into mid-later next week with development of a pronounced Bering Sea/Aleutians upper trough and warming/stablizing downstream eastern Alaska upper ridge. These amplified features are slated to be slowly but steadily progressive through these longer time frames. Associated surface based cyclogenesis and frontogenesis with upper trough development offer a threat of enhanced winds and moisture/rainfall for primarily the western half of the state with approach, with main impacts possible later next week for western Alaska to monitor, but specifics are less clear given ample individual model and ensemble member variance within a favorable pattern. 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