Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 649 PM EDT Mon Jul 03 2023 Valid 12Z Fri Jul 07 2023 - 12Z Tue Jul 11 2023 ...Synoptic Overview and Guidance/Evaluation Preferences... Alaska should stay pretty active during the medium range period (Friday-Tuesday) as upper troughing initially over western Alaska and the AK Peninsula slides eastward across the Mainland this weekend. This should act to finally break down the ridge over Southeast Alaska too. The next system diving south out of a deep low over the Arctic should reach the Bering Sea around Saturday, possibly spinning up another upper low near Western Alaska by Sunday which then lifts north blocked by ridging rebuilding over western North America into eastern Alaska early next week. More uncertainty surrounds another possible system towards the Western Aleutians late in the period as well. Synoptically, there's fairly good agreement on the large scale pattern across Alaska, but a lot of uncertainty in the details of individual systems. Compared to yesterday, the models have come into better agreement with initial troughing moving through mainland Alaska this weekend and now advertise a second upper low dropping south across the Bering Sea behind it (though with some notable differences in placement). The bigger issues come mid to later in the period with weaker systems rounding a deep low over the Arctic into the western Bering/Aleutians region, and then the details of shortwave energy south of the Aleutians and into the Gulf late period. The ensemble means show washed out systems which exemplifies how difficult these details are to resolve at these longer time scales. The WPC blend for today favored the ensemble means later in the period, but with some modest amounts of the 12z GFS and ECMWF in the blend to help maintain some definition to shortwaves/systems. ...Weather/Hazards highlights... A wet pattern is setting up over much of western and interior Alaska later this week and this weekend. Although a couple inches of total rainfall is possible, especially in the higher terrain regions, it doesn't look to be hazardous or particularly heavy. This upper troughing should keep much of Alaska cooler, with daytime highs 10-20 degrees below normal for this time of the year. The exception to this will be parts of the eastern Interior and Southeast Alaska where conditions should stay above normal and warm (with temperatures into the 70s to near 80 at times). Santorelli Hazards: -No significant hazards are expected over Alaska during this forecast period. 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