Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 700 PM EDT Wed Jun 29 2022 Valid 12Z Sun Jul 03 2022 - 12Z Thu Jul 07 2022 ...Overview and Guidance/Predictability Assessment... An almost Rex block like pattern will be in place by the start of the period on Sunday with an upper low in the Gulf of Alaska, an upper high over northwest Canada, and strong ridging across northern and eastern Mainland Alaska. There's good agreement in the models that this upper low will drop south out of the Gulf and strengthen as it interacts with another closed low off the Pacific Northwest CONUS coast. This should help to break down the Rex block allowing for troughing into Alaska and a relief to the much above normal temperatures expected across the state later this week and into the weekend. Elsewhere, there's a lot more uncertainty surrounding an upper low near far eastern Russia, embedded within larger scale troughing over the Bering Sea, and various weak shortwaves rounding the base of this trough near/south of the Aleutians. By next Wednesday-Thursday, deterministic solutions bring the main Bering Sea trough east as another upper low tries to break off and slide south of the western Aleutians. There is quite a bit of variability and uncertainty in the placement and strength of this low, which not unexpectedly gets fairly washed out in the ensemble means. Given the early period agreement, a blend of the deterministic solutions (with slightly more emphasis towards the ECMWF) was used as the basis for the WPC forecast today. By days 6-8, increased usage of the ensemble means to help mitigate the later period differences. The 12z CMC by late period seemed to be the best proxy for the ensemble means, so some inclusion of that model with used for some added system definition. This maintained reasonable continuity with yesterdays forecast as well. ...Weather and Hazard Highlights... Temperatures across eastern and northern Alaska should begin to moderate somewhat by Sunday, but still well above normal equating to daytime highs 80-85F (eastern AK) and 70-80F (North Slope) through Monday. Temperatures will cool from west to east next week as upper troughing works inland from the Bering, with much of the state below normal by next Thursday. The Northern Coast and far eastern Alaska by stay near or above normal through next week, but highly dependent on ridge placement. Southerly flow ahead of the upper low near the Alaska Peninsula/Gulf will continue to bring moderate to locally heavy rains to parts of the southern Coast region through Sunday. By Monday, much of southern Alaska should dry out, while parts of central and northern Alaska could see some enhanced precipitation in favorable upslope regions associated with a cold front pushing through interior Alaska. The Aleutians should see daily periods of light showers given generally unstable flow aloft. 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 Hazards: - Much above normal temperatures across portions of northern Alaska, Sat-Sun, Jul 2-Jul 3. 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