Alaska Extended Forecast Discussion National Weather Service College Park MD 742 PM EDT Fri Jun 27 2025 Valid 12Z Tue 1 Jul 2025 - 12Z Sat 5 Jul 2025 ...General Overview... The main theme of the overall weather pattern expected for the first five days of July will be a broad upper low/trough that will be situated over the northern Gulf, and an upper ridge axis that evolves into a closed upper high over the western mainland towards the end of the week. With an incoming upper low from the western Bering, this will tend to form an omega block pattern that will likely have some staying power from the middle of the week and beyond. Warm conditions continue across the mainland with scattered showers and storms for portions of Interior, and periods of light rain for the southern coastal areas. ...Guidance Evaluation/Preferences... The 12Z model guidance suite is in good agreement with the low over the northeastern Gulf, but struggles with incoming shortwave energy from the Bering Sea that affects western mainland Alaska and the Aleutians that is ahead of the larger upper low that follows later in the week. This shortwave energy will tend to reinforce the upper low that will already be in place across the northern Gulf. Speaking of the next low entering the Bering late in the week, the GFS seems to differ the most from the consensus by being displaced well to the southwest, and this continues going into next Saturday, so it was weighted less in the forecast blend beyond Wednesday. The ensemble means were gradually increased to about half by next Friday. ...Weather/Hazards Highlights... A broad upper level low with reinforcing surface lows will be present across the northern Gulf through most of the forecast period. The upper ridge axis appears likely to build back in to the north across the central and northern mainland going into the middle of next week and potentially forming an omega block type pattern as a closed upper high likely develops. Meanwhile, a trough approaches from eastern Siberia for the middle to end of the week, but does not appear to be all that impactful for now. There will likely be an increase in shower and thunderstorm coverage going into early next week across eastern portions of the Interior. Relatively moist northeasterly flow approaching the central and eastern portions of the Alaska Range will increase the potential for heavier rainfall, with the highest totals where there is an upslope flow component where up to an inch of rainfall will be possible. This rainfall would help to mitigate any ongoing fire weather concerns. Showers are also expected for southeast Alaska as moist onshore flow continues courtesy of the loitering low over the northern Gulf. Hamrick 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