Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 737 PM EDT Sat Jul 1 2023 Valid 12Z Wed Jul 5 2023 - 12Z Sun Jul 9 2023 ...Synoptic Overview and Sensible Weather... A strong upper low just south of the eastern Aleutians Wednesday morning is forecast to lift slowly northeastward across the Alaska Peninsula and then Bristol Bay by Friday. A weaker second upper low might develop over the western Bering around the end of the forecast period next Sunday. East of the big upper trough will be a downstream ridge axis extending across northeastern mainland Alaska and the Panhandle region into the Yukon Territory, but this ridge may start breaking down some going into next weekend as shortwave energy from the west impinges upon it. The storm system lifting north across the Alaska Peninsula midweek is expected to produce moderate rainfall across the windward terrain of the Alaska Peninsula to the Kenai Peninsula and portions of the Chugach Mountains through Thursday night, with some rainfall totals up to one inch possible. Scattered showers and a few thunderstorms are expected from the southwest mainland and across the Interior to the Brooks Range. Temperatures are expected to be mild across much of the Interior, with highs reaching well into the 70s for the lower elevations. Readings mainly in the 60s are expected for the North Slope, and upper 40s to lower 50s near the Arctic Coast. ...Guidance Evaluation/Preferences... The 12Z model guidance suite is in good overall agreement on most synoptic scale features through the end of the week, so a general model blend suffices as a starting point in the forecast process. There has been a slightly faster trend in the guidance today for the track of the low pressure system early in the forecast period. Going forward into next weekend, the deterministic guidance differs on the timing and position of the next weaker disturbance across the Bering, and the degree of ridge breakdown across the eastern Gulf region. The use of the ensemble means increased to about 50% by next Sunday. Hamrick 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