Alaska Extended Forecast Discussion National Weather Service College Park MD 624 PM EDT Sat Jun 21 2025 Valid 12Z Wed 25 Jun 2025 - 12Z Sun 29 Jun 2025 ...General Overview... The pesky omega-style blocking pattern across the Alaskan domain and vicinity is forecast to relax a bit beginning early next week. The now familiar upper-level anticyclone centered over mainland Alaska is forecast to retreat southeastward as a deep upper low downstream moves away into the Pacific Northwest through the short-range period. It appears that the retreated upper high will reestablish near/over the northeast corner of Alaska early next week and then progress northward into the Arctic Ocean midweek. Meanwhile, the Bering Sea mean closed upper low should slide very slowly east-southeast toward the eastern Aleutians and approach the Alaskan Peninsula through next week into next weekend. Relatively weak waves or triple-point lows are forecast to eject eastward across the North Pacific and with downstream energy transfer consolidate over the Gulf of Alaska into next weekend as the retreated upper ridge will remain over northeastern Alaska and the Yukon territories. ...Guidance Evaluation/Preferences... Prefer a blend of reasonably well clustered guidance of the 12 UTC GFS/ECMWF/Canadian/UKMET (60%) and respective ensemble means (40%) in a pattern with above normal predictability and WPC product continuity through medium range time scales. Opted to manually deepen mainly offshore surface low pressure systems as warranted by favorable upper support to offset weakening inherent to a broad blending process as used today. ...Weather/Hazards Highlights... It generally remains the case that With the anticipated retreat of the upper high over mainland Alaska, the afternoon heat across the Yukon Flats is forecast to moderate early next week, with high temperatures falling into the 70s. Underneath the retreating upper high, there will also be a lingering lower-level front across northern Alaska where scattered showers and thunderstorms are expected daily along the Brooks Range and across the eastern Interior including Fairbanks through next week. Daily rainfall amounts could locally exceed one inch across portions of the eastern Interior. This rainfall may prove helpful to mitigate some of the ongoingt wildfire risk as temperatures moderate. The southern coastline and the Panhandle should be relatively dry leading into midweek. However, rain associated with the next cyclone should be moving through the Aleutians from west to east by then as rain chances increase along the Alaska Peninsula. Farther offshore, as low pressure waves/triple-point lows eject eastward across the Gulf of Alaska, rainy weather can be expected to reach the southern coastline and the Panhandle from west to east through the remainder of next week. The southwestern coastal areas, eastern Aleutians and the Peninsula can expect more widespread rainfall midweek next week when the Bering Sea low edges closer. By late next week, there is a potential for localized heavy rainfall across the climatologically rainy region of the Kenai Peninsula and eastern Alaska Peninsula as the Gulf of Alaska low is forecast to become more dominant. Temperature- wise, seasonable conditions are expected near the southern coast and the larger cities, with highs generally in the 50s and 60s. 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