Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 738 PM EDT Sun Aug 6 2023 Valid 12Z Thu Aug 10 2023 - 12Z Mon Aug 14 2023 ...Synoptic Overview... A large upper level gyre is expected to be in place across the northern Bering Sea for the second half of next week, and an upper level trough with embedded shortwaves across the Gulf region. The upper ridge axis over far northwestern Canada is forecast to slowly break down some going into next weekend, but should remain across the Yukon and Northwest Territories. The main Bering low should gradually drop south toward the Aleutians by Saturday and a shortwave pivoting around it should spur surface cyclogenesis south of the Alaska Peninsula with the surface low lifting northeastward and bringing more widespread rain for south-central portions of the state and also extending across the southeast Panhandle region. ...Guidance Evaluation/Preferences and Predictability Assessment... Models and ensembles for the 12Z model cycle are in good overall synoptic scale agreement across the Alaska domain for the middle to end of the week, with some minor timing differences with shortwave energy crossing the North Pacific and the northern Gulf. Looking ahead to the weekend, the deterministic guidance continues to indicate an intensifying surface low south of the Aleutians, with the CMC the farther northwest solution but weaker compared to earlier runs, and the GFS is indicating a stronger surface low with potentially greater impacts should that solution verify. The greatest degree of model spread exists over the northern Gulf region and also northwestern Canada by the second half of the forecast period, and the best agreement over western and central portions of mainland Alaska. Taking these factors into account, the WPC front/pressures forecast is primarily derived from a nearly multi-deterministic model blend through Friday, and then increasing use of the ensemble means to about 50% by next Sunday-Monday. ...Weather/Hazards Highlights... The high latitude upper ridge over the northeastern mainland into the Yukon will continue to support above normal temperatures, but trending cooler than what is expected in the short range forecast period. Daytime highs may reach the 80-85 degree range over the Yukon Flats, while the North Slope could see readings rise into the 70s well away from the coast. Highs should mainly be in the 60s and 70s across most of the mainland by next weekend, and mid-upper 50s for most of the coastal areas. Low temperatures should generally be above normal across most of the state. In terms of precipitation, onshore flow across the southern mainland coastal areas and also the Alaska Peninsula will favor rounds of moderate to occasionally heavy rainfall, with some localized totals of 2-4 inches possible across the windward terrain near the coast. This will also hold true for portions of the southeast Panhandle, with the greatest impacts there expected Saturday night and into Sunday as a moisture plume is directed towards the coast. Depending on how strong the weekend storm gets, high winds may be an issue for the maritime and coastal areas. 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