Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 749 PM EDT Sun Sep 1 2024 Valid 12Z Thu Sep 5 2024 - 12Z Mon Sep 9 2024 ...Guidance Evaluation/Preferences... The 12Z model guidance suite features good overall synoptic scale agreement across the Alaska domain for the end of the work week, although the GFS is slightly stronger with the shortwave trough dropping southeast across the Aleutians through early Friday. The Gulf low is still depicted reasonably well going into Saturday, but greater model differences appear across the Arctic and the western Bering regarding the arrival of the next shortwaves, and even more apparent going into next Monday. A nearly even blend of the available deterministic guidance served as a good starting point for fronts and pressures through Friday, and then gradually incorporated up to 50% ensemble means by next Monday. ...Weather/Hazards Highlights... An organized low pressure system approaches the southern mainland Alaska coast by late Wednesday night, while an incoming system from the west/Bering Sea merges with it. This will keep conditions quite rainy from South-Central AK into the Alaska Panhandle as the mid-to upper-level trough remains nearly anchored in place. A total of 4-8 inches of QPF is in the grids for the forecast period across the favored terrain, which is not especially unusual for early autumn and reasonably close to continuity. Gale force winds are expected for the coastal and offshore waters as the low approaches, which could lead to higher tides. The incoming low pressure system across the Bering may also result in periods of rain for western mainland Alaska, accompanied by some stronger winds near the coast. Northern stream shortwaves move across northern Alaska, keeping the arctic drape near the Brooks Range and generally cooler conditions across the North Slope. 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