Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 749 PM EDT Thu Jun 22 2023 Valid 12Z Mon Jun 26 2023 - 12Z Fri Jun 30 2023 ...Pattern Overview and Weather/Hazards Highlights... The dominant feature for the first half of next week will be an anomalous and nearly stationary closed upper low and associated surface low over the southeastern Bering Sea, with multiple shortwave perturbations pivoting around the base of it. The first wave of low pressure that is expected to arrive this weekend will be rapidly weakening by Monday morning, with wind and rain tapering off in intensity. A second storm system is likely going into Wednesday, but it should be weaker in intensity compared to the weekend event. Portions of the Interior will also have scattered showers and a few thunderstorms, but overall QPF should be light in most cases. Some locally heavier rainfall will be possible near the Brooks Range during the Monday-Wednesday time period. In terms of temperatures, high temperatures are expected to rise into the upper 60s to middle 70s for many of the Interior valleys, and 50s/low 60s for the central and coastal areas. A few locations across the Yukon Flats may reach 80 degrees. The Arctic Coast will likely remain cooler with highs generally in the 40s/low 50s most days. ...Guidance Evaluation/Preferences... The 12Z model guidance suite has good overall synoptic scale agreement to start the week, and a multi-deterministic model blend suffices as a good starting point in the forecast process through Tuesday. The next disturbance pivoting around the upper gyre midweek is generally weaker in the guidance, although the GFS continues to be the strongest solution with this second feature, and a little faster than the weaker CMC/ECMWF. All of the guidance agrees that the main upper low will remain nearly anchored in place across the southern Bering Sea through about Tuesday night, before drifting eastward across the Alaska Peninsula and towards the northern Gulf. Model spread increases substantially going into Thursday and Friday with below average forecast confidence by Day 8. The ensemble means accounted for about 50-60% of the forecast blend by the end of the week. 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