Alaska Extended Forecast Discussion National Weather Service College Park MD 654 PM EDT Fri May 9 2025 Valid 12Z Tue 13 May 2025 - 12Z Sat 17 May 2025 ...Synoptic Overview... A very common synoptic pattern for Alaska will unfold through much of the upcoming workweek into the weekend. A large vertically stacked low centered over the Bering will draw several different impulses of energy from the jet stream over the Pacific, turning them north into Southwest Alaska, then absorbing them. Each successive impulse of energy will nudge the overall trough and low a bit eastward with time, but very little will change in the broader pattern through the period. Each impulse of energy will have its own surface low associated with it. The first on Tuesday will move eastward along the Aleutians, then turn north along the Southwest Alaska coast before being absorbed into the aforementioned larger, vertically stacked low. As it turns north, it will support the development of a triple point low near Kodiak Island, which will also move north into the Island and rapidly dissipate. All of this is well agreed upon in the guidance. The eastward extent of the warm and occluded fronts will move into the Panhandle and the rest of the Gulf Coast through Thursday, resulting in very unsettled weather for the coastal areas, but this front will not be particularly strong, so all of the associated rainfall is well within normal thresholds. On Friday and Saturday, there is little agreement in the guidance as to whether additional lows will form in the Gulf along with the fronts, or just the fronts themselves with no lows. The difference may be a bit more rain if the lows form, but regardless, rapid northward movement of the fronts in broad onshore flow across the Gulf will keep the area wet into the weekend. Elsewhere, the Aleutians will also remain unsettled due to the persistent main low which will remain over the central and eastern Aleutians through the period. For northern Alaska, very persistent high pressure centered well off the Arctic coast will keep a steady northerly onshore wind across the North Slope, which will dam up against the Brooks Range. This will keep conditions cold with highs in the teens and 20s and cloudy. Immediately south of the Brooks Range on the dry side, however, will be the sunniest area of Alaska as the same northerly flow dries out the air mass. Very slow movement and persistence in the overall pattern will keep the weather unchanging day to day. ...Guidance Evaluation and Preferences... For the most part, as is typical, the guidance was in reasonably good agreement through days 4 and 5 (Tue and Wed), gradually splitting apart across D6/Thu, then little agreement for Days 7 and 8. The standard model blend was used therefore, with heavy use of the deterministics (GFS/EC) for Days 4 & 5, then rapid trending towards ensemble blends through Days 7 & 8. No big outliers overall though, as the general agreement early becoming wide disagreement late didn't signal any one model being an outlier. ...Weather/Hazards Highlights... No hazards are expected through the period. Gusty winds across the Bering will diminish Tuesday, with small areas of gusty winds with each low moving north out of the Pacific, as well as in the gaps such as Shelikof Strait and through Iliamna Lake. Periods of heavy rain are likely Tuesday and Wednesday on the Pacific/Gulf side of the Aleutian Range, Kodiak Island, and the southern Alaska Range but here too nothing out of the ordinary is expected. && Wegman 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