Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 631 PM EDT Fri Jul 01 2022 Valid 12Z Tue Jul 05 2022 - 12Z Sat Jul 09 2022 ...Overview and Guidance/Predictability Assessment... The upper pattern will slowly transition toward more troughing out of the Bering Sea next week as the upper high over NW Canada slowly retreats to the southeast. This will gradually introduce cooler temperatures to the mainland with increased rain chances. The models seem in best agreement into days 4/5 (Tuesday/Wednesday). The ensembles remain in very good agreement through the end of next week, with expected differences in the speed and depth of the incoming trough per the cluster analysis, but within the typical spread for a 6-8 day forecast in an overall pattern with average to above average predictability. The surface pattern on the other hand remains tricky/difficult to depict, but will likely be devoid of any robust system, and will rather unusually feature a lead baroclinic boundary progressing eastward into the state from the Bering in tandem with main upper troughing, with waves of low pressure possible along the front south of the Aleutians that may lift toward the AKPen and South-central Alaska into late next week. Deterministic models differ on timing/strengths, especially by then. With increased uncertainty in these details by next Thursday-Saturday. Accordingly, and for max product continuity consistent with predictability, switched from a composite 12 UTC GFS, ECMWF, UKMET and Canadian model blend days 4/5 (Tue/Wed) to a GEFS/ECMWF ensemble mean blend for days 6-8 Thu-next Saturday as a base for the WPC guidance product suite. ...Weather and Hazard Highlights... Well above normal temperatures at the start of the period over eastern Interior locations will trend back toward more typical values by midweek as cooler temperatures spread eastward from the Bering. By late in the period, much of the mainland should moderate. Dry weather will prevail through early next week as the upper ridge axis moves through. By midweek, widespread and locally enhanced rain chances will increase as southwest flow brings in more moisture from the North Pacific, including across the Interior/northern Alaska. A slowly-moving frontal boundary working to just southeast of the Aleutians may enhance rainfall duration over Kodiak Island and south-central Alaska in particular late period, depending on the trough orientation/strength and surface front. Regardless, most of the state will see some welcome rains next week. Schichtel 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 Hazards: - Heavy rain across portions of the southern coastal sections of Alaska, Fri, Jul 8. 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