Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 642 PM EDT Sun Jul 03 2022 Valid 12Z Thu Jul 07 2022 - 12Z Mon Jul 11 2022 ...Heavy Precipitation Threat for the Alaskan Southern Tier... ...Pattern Overview and Weather/Hazard Highlights... An active medium range weather pattern should emerge for parts of Alaska. The weather pattern by Thursday will feature closed lows/troughs centered over the Arctic Ocean and southeastern Bering Sea on the periphery of a warming upper ridge from western Canada to the Alaskan mainland. Guidance has trended to transitioning more ample southeastern Bering Sea closed low/trough energies toward Southwest Alaska/Alaskan Peninsula/Kodiak Island then south-central Alaska into Friday/Saturday where sustained and deepened Gulf of Alaskan moisture feed offers a protracted threat for moderate to locally terrain enhancing precipitation. Additional downstream system progression with the main closed low though should become increasingly inhibited by the shielding upper ridge, so less certain upstream flow of additional Bering Sea/Aleutians energies into the backside of this system should tend into early next week act to reform a main closed low position underneath over the west-central Gulf of Alaska as a maritime threat. Large circulation proximity and wrapping energies should bring additional periods of moisture/precipitation inland into southern to southeast Alaska. Meanwhile, the Arctic vortex should stay well to the north/northwest of the North Slope. However, northward ejecting impulses and moisture northward through Southwest Alaska and into the Interior on the western periphery of the slowly eroding upper ridge should meanwhile fuel multi-day local rain chances. ...Guidance/Predictability Assessment... The synoptic scale pattern evolution remains well accounted for in guidance at medium range time scales, but individual model solutions characteristically vary more significantly with embedded systems/phasing over next weekend. This likely equates to a period with near normal forecast predictability. For max product continuity consistent with uncertainty, the WPC Alaskan product suite was primarily derived from a composite of the 12 UTC GFS, ECMWF, UKMET and Canadian model blend Thursday into Saturday before switching to a ensemble mean blend of the compatible GEFS/NAEFS/ECMWF means onward through days 7/8 (next Sunday/Monday). WPC continuity is well maintained with this forecast plan. 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 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