Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 647 PM EST Sun Jan 23 2022 Valid 12Z Thu Jan 27 2022 - 12Z Mon Jan 31 2022 ...Overview... The latest guidance supports the development of an Omega block pattern setting up over the Alaska region by Thursday with the amplified ridge axis over the eastern Bering Sea. This would act to keep storm systems confined to the Gulf/southeast Alaska and rotating northward across the western Aleutians. Shortwaves may attempt to temporarily break down the ridge through the period, but an overall blocky pattern should hold strong into early next week with possibly a slight eastward shift. ...Guidance/Uncertainty Assessment... The latest 12z model guidance is in good synoptic scale agreement on the Omega block pattern over the region through the period, though plenty of uncertainty in the details. In the Gulf, the GFS and CMC are displaced farther north than the ECMWF with a surface and upper low. The low should eventually lift towards the north and become reinforced through the period by incoming smaller scale shortwaves/systems. Despite the relatively good large scale agreement, the smaller scale differences offers low confidence in the details affecting precipitation across southeast Alaska. To the west, guidance suggests several deeper surface lows may move towards the Western Aleutians through the weekend, but again presents typical uncertainties in placement, strength, and timing. By early next week, the CMC and ECMWF show a much stronger block and actually close off an upper high near western Alaska next Monday (though the CMC is displaced well to the north of the ECMWF). The GFS continues to support amplified ridging over the region, but not quite as blocky. The WPC progs for today over Alaska used a majority blend of the deterministic GFS, ECMWF, and CMC through day 6. After that, increased contributions from the ensemble means to help mitigate the harder to resolve differences at these longer time scales. This approach keeps the forecast fairly consistent with yesterdays WPC progs, as well as those downstream across the CONUS. ...Weather/Hazard Highlights... Arctic High pressure holding strong during the medium range period will keep much of Mainland Alaska cold and dry. Meanwhile, storm systems in the Gulf will translate to unsettled conditions along the Southeast coast and Panhandle regions. Moderate to heavy precipitation will shift slowly southward through the period with conditions tending to dry out by early next week as the upper low moves farther south and some upper ridging tries to build in. The eastern Aleutians/Peninsula should stay quiet through much of the period although a couple of storm systems to the west likely brings renewed wet weather to the western Aleutians, with periods of gusty winds as well. Temperatures across most of the state should start out below to much below normal on Thursday (except the Southeast), though ease with time as the upper ridge axis shifts slowly inland. By next Sunday-Monday, parts of the Western Alaska and North Slope regions may see temperatures back to above normal, with the Panhandle transitioning to much below normal. Santorelli 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