Alaska Extended Forecast Discussion National Weather Service College Park MD 721 PM EDT Sat May 31 2025 Valid 12Z Wed 04 Jun 2025 - 12Z Sun 08 Jun 2025 ...Heavy rain and gusty winds to impact portions of the Southern Coast and Alaskan Panhandle... ...Overview... An upper low over the Bering Sea early next week will weaken as it drifts inland by mid-week. A couple of shortwaves will swing south across the Aleutians helping to reinforce troughing over the western Mainland and sending a couple of weak surface lows towards the Gulf. This should help maintain a generally unsettled and wet pattern for southern and southeast Alaska, with moderate to locally heavy rains in some spots. By late week, ridging may build across the Gulf and Panhandle but with uncertainty in how strong it is and how quickly a trough to the west can track towards the Gulf next weekend. This trough looks like it may send another surface low towards the Peninsula or southern Coast. ...Guidance Evaluation/Preferences... The latest guidance shows reasonable agreement through much of the period on the large scale pattern, but plenty of uncertainty in the details of individual lows. Greater uncercertainty begins to build late week in regards to how amplified and progressive the upper pattern becomes. The GFS shows less amplification of a ridge over the Gulf which allows an upstream trough/shortwave to progress much quicker than consensus. There seems to be a bit more agreement for a little bit stronger ridge and a slower or more northerly track for the shortwave and its associated surface low. Regardless, there is agreement a surface low will traverse south of the Aleutians but whether it moves more into the Gulf (GFS) or the Peninsula/southern Coast (ECMWF and CMC) remains to be seen. The WPC forecast for today used a blend of the deterministic models for the first few days of the period, quickly transitioning to a majority blend of the ensemble means to help mitigate the greater detail differences later in the period. ...Weather/Hazards Highlights... Weak surface lows into/towards the Gulf will continue a generally wet pattern for much of southern and southeast Alaska. An intial system Wednesday-Thursday will allow for a period of moderate to locally heavy rains for the Southern Coast and Panhandle. Later in the week, rainfall intensity should decrease but showers will continue all along the coastal regions from the Aleutians to the Panhandle, and even farther inland towards the Brooks range. Another trough towards the Gulf will increase precipitation again for parts of the southern Coast and Panhandle but with much more uncertainty in the amounts and impacts. High temperatures near and under the initial upper low are likely to be cooler than average, covering southern Alaska early week. Temperatures may moderate somewhat behind this trough and ahead of the next one. The North Slope should also see colder than normal temperatures under the influence of an Arctic high. Santorelli 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