Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 748 PM EDT Fri Jul 29 2022 Valid 12Z Tue Aug 02 2022 - 12Z Sat Aug 06 2022 ...Overview... Strong high pressure in both the upper levels and at the surface is forecast to retrograde and meander across the midlatitudes of the Pacific between Alaska and Hawaii. Fairly progressive flow is likely across southern Alaska to the north of the high, with one upper/surface low moving across the Panhandle Tuesday-Wednesday and another forecast to move across the Bering Sea and toward the southwest mainland around Thursday. These features will bring chances of rain to the southern mainland and Panhandle. Then an Arctic upper low is forecast to edge southward toward Interior Alaska late next week, bringing cooler temperatures and possibly some light precipitation. ...Guidance/Predictability Assessment... Recent model guidance indicates reasonably good agreement for the timing of the first upper/surface low tracking across the southeast mainland and Panhandle Tuesday-Wednesday, namely a continued faster track in the latest GFS/ECMWF runs though a bit slower in the CMC. With the next upper low and associated surface low moving across the Bering Sea midweek and into the southwestern mainland likely on Thursday, there has also been a faster trend over the past day overall, though there are still timing differences. The 12Z ECMWF seemed to be a good middle ground between the faster GFS/GEFS and the slower CMC and UKMET, so favored the EC as well as some EC ensemble mean in the forecast blend through around day 6/7. By late next week, there is fairly good agreement for the influence of the Arctic upper low sinking south, but with ample detail differences. Thus transitioned the forecast blend to 60 percent GEFS/EC ensemble means by the end of the period amid increasing uncertainty in the details. ...Sensible Weather... Some gusty winds across the southwestern mainland/Alaska Peninsula on Monday should be decreasing as the period begins Tuesday and the surface low weakens. Enhanced rainfall amounts could continue in southeastern Alaska and the Panhandle Tuesday behind the system. Then, modest rainfall amounts could shift from the Aleutians into the southern half of the interior, moving west to east with the low system around late Wednesday into Thursday, then into the Panhandle Friday. The low pressure systems will also cause abundant clouds, with perhaps some clearing in between allowing for milder temperatures into the 70s in the Tanana Valley. Elsewhere, low temperatures should be around average while highs from the Alaska Range southward may be generally below average. However, coastal regions of the North Slope can expect above normal temperatures through much of next week, until Arctic troughing approaching will cool down temperatures late week. Some showery conditions are possible across the North Slope for the latter part of the week along a frontal boundary. Tate Hazards: - Heavy rain across portions of mainland Alaska, Mon, Aug 1. - High winds across portions of mainland Alaska and the Aleutians, Mon, Aug 1. 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