Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 741 PM EDT Wed May 7 2025 Valid 12Z Sun 11 May 2025 - 12Z Thu 15 May 2025 ...General Overview... Much of mainland Alaska will likely be situated between two upper-level gyres through the medium-range period. The most active weather to affect the Alaskan domain will be associated with the gyre centered generally over the Bering Sea, as frequent arrival of moderately strong cyclones will keep weather unsettled for the Aleutians and along the southern coastline of mainland Alaska through the middle of next week. Southwestern Alaska should see more widespread precipitation moving in by late this weekend with the arrival of the second cyclone. ...Guidance/Predictability Assessment... Models and ensemble means indicate that there will be three moderately strong cyclones to track across the Aleutians, then weaken and be absorbed into the upper-level gyre centered over the Bering Sea during the medium-range period. All guidance show good agreement on the first cyclone to weaken over the Bering Sea by later this weekend, as the second cyclone quickly approaches the central Aleutians. Today's guidance indicates that a better- defined frontal band with possibly heavy rain across the Panhandle should be tapering off by Sunday. Meanwhile, models continue to indicate appreciable uncertainties on how far and how fast the second cyclone tracking across the Aleutians into the Bering Sea Sunday into Monday will reach southwestern Alaska. The GFS still favors a faster solution but with occasional jumps much farther to the west. The ECMWF today has accelerated the system much closer to southwestern coast of Alaska by Monday morning compared with yesterday's runs. Nevertheless, its ensemble means remain notably slower. For the third cyclone, the ensemble means from global models show good agreement on bringing this cyclone on an east- northeasterly course along the Aleutians through midweek next week. The WPC medium-range forecasts for Alaska begin with a blend of 40% 12Z EC/00Z EC mean, 40% 12Z GFS/GEFS, together with 20% from the CMC/CMC mean, followed by slightly higher percentages toward the 00Z EC mean on Day 5. The blend then transitions to mostly consisting of the ensemble means toward the end of the forecast period. The blend maintains good continuity with yesterday's WPC forecasts with a slightly faster progression of the second cyclone moving toward southwestern Alaska. ...Weather/Hazards Highlights... Any enhanced rainfall and high-elevation snow in the Panhandle due to the passage of a frontal system trailing southeast from a compact cyclone over the Gulf of Alaska should be gradually tapering off on Sunday. Meanwhile, unsettled weather is forecast to continue through the Aleutians while getting more frequent and widespread by Sunday with the arrival of a moderately strong cyclone from the Pacific. This system should spread rainy weather and high-elevation snow progressively farther into southwestern Alaska and farther east along the southern coastline early to middle of next week with amounts not expected to be excessive. A third cyclone taking a east-northeasterly track should bring additional unsettled weather to the Aleutians through the middle of next week. Meanwhile, scattered precipitation associated with the second cyclone could reach the southern interior section of Alaska and the Panhandle during the middle of next week. Temperatures are expected to be above average across southwestern and interior mainland Alaska while from the North Slope to the Brooks Range will be below normal. A warming trend is forecast to set in across northern Alaska during midweek next week. Kong 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