Alaska Extended Forecast Discussion National Weather Service College Park MD 759 PM EDT Wed Jul 16 2025 Valid 12Z Sun 20 Jul 2025 - 12Z Thu 24 Jul 2025 ...Guidance Evaluation and Preferences... Today's model guidance follows yesterday's atypical stance: i.e., the ensemble mean solutions show excellent agreement out to Day 8, with their consensus most consistent with the fastest end of the deterministic solution spread. This skewed mean solution is most apparent with a Bering Sea cyclone at 500 mb level which is forecast to lift northeast toward the west coast of mainland Alaska by early next week. The fastest guidance today is the 12Z ECMWF, which is faster than the 00Z EC mean and the ensemble mean consensus. Similar to yesterday, today's WPC forecast guidance is based on the consensus of the ensemble means, which leans toward the faster end of the deterministic solution spread. Meanwhile, a weakly-defined omega blocking pattern initially across the Arctic Ocean north of mainland Alaska is forecast to evolve into a closed high north of Siberia by midweek next week. Over the Alaskan domain, an upper-level ridge is forecast to amplify somewhat and nudge eastward into the eastern portion of Alaska by early next week when southwesterly flow ahead of the Bering Sea low transports increasing moisture into southwestern Alaska. The WPC medium-range forecast package today begins with a 40% blend of the 12Z ECMWF/00Z EC mean, 40% from the 12Z GFS/GEFS, and 20% from the 12Z CMC/CMC mean, which quickly transitions to mostly comprising of the ensemble means by Day 6. When comparing with yesterday's forecasts, this blend yields a solution that depicts a slightly faster northward motion of the Bering Sea low, which gradually opens up into a trough with time. The attached cold front now shows a much faster eastward progression across mainland Alaska through early next week. ...Pattern Overview and Weather/Hazards Highlights... The medium-range period should begin with a lull in the rain before an increasingly wet pattern gradually overspreads southwestern Alaska and then up the west coast heading into midweek next week. Rainfall amounts are not expected to reach heavy criteria for much of these areas except along the Alaska Range by next Tuesday. Wet snow can be expected for the higher elevations. Meanwhile, scattered showers and embedded thunderstorms are expected across the central section of mainland Alaska with a better chance of seeing these activities this weekend. As the Bering Sea cyclone occludes and the associated cold front reaches mainland Alaska, rain and high-elevation snow are forecast to overspread the Brooks Range from west to east for early to the middle of next week. Temperatures should average above normal for the northwestern and southeastern Alaska including the Panhandle through the medium- range period. Portions of the Panhandle should feel very mild high temperatures into the 70s early next week. The Southwest should average slightly below normal especially with the arrival of precipitation from the Bering Sea cyclone followed by the passage of the cold front next week. The North Slope should start out below normal this weekend as a surface high pressure system in the Arctic Ocean feeds cool winds into the region. A moderating trend is forecast through early next week for the North Slope as the high pressure system weakens ahead of the Bering Sea cyclone, but a cool down can be expected once again midweek due to an increasing chance of precipitation. 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