Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 733 PM EDT Tue Jun 08 2021 Valid 12Z Sat Jun 12 2021 - 12Z Wed Jun 16 2021 ...Overview and Guidance Evaluation... Since yesterday, model guidance has come into relatively good agreement among each other. The main storm of interest will be an occluded cyclone moving toward the Aleutians that will likely be re-energized as an upstream upper-level trough merges with the system over the Bering Sea during the weekend. The merger should reach peak intensity on Monday as it edges into the Alaska Peninsula before sliding off just to the south toward the Gulf of Alaska by midweek. A general model compromise trending toward the ensemble means for Days 7-8 should work fine as a starting point. The 12Z ECMWF tracked the low a bit faster to the east than the 12Z CMC and the GFS by Days 7-8, as were their ensemble means. This general model blend yielded a solution that did not stray too far from WPC continuity. Elsewhere, a stationary front should remain draped across the northern portion of Alaska through the medium-range period. ...Weather/Threats Highlights... The upper shortwave edging in from Siberia during the weekend should promote periods of precipitation that should be best organized over about the northwest half of the mainland. Recent guidance has generally trended weaker with this shortwave. Expect precipitation to become lighter and more scattered by late weekend and early next week as the shortwave departs and an upper ridge builds into the mainland from Canada. The strengthening system that tracks into the Aleutians/Bering Sea will spread a broad area of moisture across the Aleutians and into much of the Alaska Peninsula early next week. The Aleutians may see a period of enhanced rain/winds during the weekend and the Alaska Peninsula/Kodiak Island could see a couple days or so of focused rainfall as the occluded cyclone is forecast to reach peak intensity on Monday. Cool high temperatures over a majority of the state should gradually moderate with time as shortwave energy lifts to the north of the state by late weekend/early next week and then upper ridging builds. By late in the period the Panhandle and parts of Southcentral as well as portions of the northwestern mainland may still be somewhat below normal for highs. For lows, expect moderately below normal readings over parts of the Interior and western mainland as well as the Panhandle plus far southeast corner of the mainland, while remaining areas should be above normal. The coverage of above normal lows should increase toward midweek. Kong/Rausch No significant hazards are expected over Alaska during this forecast period. Additional 3-7 Day Hazard information can be found on the WPC medium range hazards 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