Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 752 PM EDT Sun Jun 16 2024 Valid 12Z Thu Jun 20 2024 - 12Z Mon Jun 24 2024 ...Overview and Guidance Evaluation/Preferences... Most of mainland Alaska will be situated under a narrow upper level ridge axis extending from northwestern Canada going into the middle to end of the week. A compact upper level polar is forecast to be just south of Bering Strait for the end of the week, with gradual weakening going into next weekend. Meanwhile, the main storm track across the North Pacific is expected to feature two low pressure systems, with the lead system approaching the southeast Panhandle going into Saturday, and the second one passing south of the Alaska Peninsula Sunday/Monday. Overall, the latest model guidance is in above average agreement across the Alaska domain to close out the week, and even reasonable agreement for next weekend with the main synoptic scale features. The CMC is on the northwestern edge of the guidance with the polar low over the Bering Sea, compared to the more clustered GFS/ECMWF/UKMET solutions, and weaker with the second North Pacific shortwave later in the forecast period. Going into Sunday, the GFS is over the southwestern mainland coast with the polar low and well southeast of the GEFS mean. There is better agreement among the ECMWF/ECENS. The ensemble means accounted for about 40-50% of the forecast blend going into next Monday. ...Weather/Hazards Highlights... Isolated to scattered showers and thundershowers can be expected most days across the Interior during the afternoons and early evenings, and some generally light onshore flow induced showers for the southern coastal areas. The greatest QPF is expected across the Alaska Range and portions of the Brooks Range, along with southeastern mainland Alaska. Depending on the evolution and track of a surface low over the eastern Gulf by next weekend, a more organized round of rain could approach the southeast Panhandle, although it's not expected to be a major event. Areas north of the Brooks Range should generally remain dry with the Arctic high exerting its influence across the North Slope and Arctic Coast. In terms of temperatures, afternoon highs are expected to reach well into the 70s for many areas across the Interior, perhaps reaching 80 degrees for the Yukon Flats, and also just north of the Alaska Range over the weekend. Overnight lows here should also be rather mild with readings bottoming out from the upper 40s to middle 50s. The Arctic Coast will likely remain chilly with onshore flow from the Arctic Ocean, with highs generally from the middle 30s to middle 40s. 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