Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 459 PM EDT Tue Jul 09 2024 Valid 12Z Sat Jul 13 2024 - 12Z Wed Jul 17 2024 â€Heavy Rainfall Threat from Southwest to Southern Alaska Friday-Sunday†...Overview and Guidance Evaluation/Preferences... The latest guidance solutions seem reasonably well clustered to cover an active period of Alaskan weather in an overall amplified and dynamic flow pattern. A deep layer cyclone is forecast to shift from the Bering Sea into the Gulf of AK, escorted eastward by a pair of systems across eastern Siberia and ejecting eastward from Sakhalin Island. Prefer a 12 UTC GFS/ECMWF/UKMET/Canadian composite blend, with some reliance on 12z NAEFS/00z ECMWF ensemble means later in the forecast period to account for the number of surface cyclones which may eject northeast toward the AK Peninsula from the northeast Pacific. The QPF weighed less on the drier 12z GFS solution. This forecast plan maintains reasonable continuity. WPC manual edits were applied to better depict the strength of the main organized surface systems that seem to have the most favorable mean upper support as an offset to inherent smoothing from the blending process. ...Weather/Hazards Highlights... Much of Alaska should be quite wet and unsettled, which should also help bring some relief to wildfire activity. Winds could reach gale force in the Bering Strait and local areas which normally show wind enhancement/funneling near south-central AK. Inland impacts from West/Southwest Alaska through the Alaska Peninsula/Kodiak Island, South-Central and then Southeast Alaska late week through next weekend, and the AK Panhandle early next week. Storm systems will remain prone to develop and evolve/linger over the eastern Bering and downstream into the Gulf of Alaska. This portends a protracted period with potential for cumulative heavy rain, 1-3" areal average amounts and local amounts in the 3-5" range possible in the terrain. High temperatures will be more evenly distributed, with 70s in the central Valley, 40s on the North Slope, and 50s and 60s elsewhere. Subfreezing lows should be constrained to the higher terrain of the Brooks Range and the various ranges across south-central and southeast AK. Roth 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