Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 527 PM EDT Tue Jul 28 2020 Valid 12Z Sat Aug 01 2020 - 12Z Wed Aug 05 2020 ...Overview and Guidance Evaluation... As the deep upper low currently over the Arctic retreats/weakens to the northeast later this week, another on from the Bering Sea will move eastward into Southwestern Alaska with another in the Gulf this weekend. The pattern will attempt to weaken into broad troughing next week with smaller-scale features after more than a week of blockier flow. The latest 12Z deterministic guidance showed good agreement with the ensembles Sat-Mon with the Bering system before they dispersed from the ensemble consensus. Could not rule out much from the models though the 12Z ECMWF/Canadian were to the south of the means and the GFS/UKMET were to the north, favoring a broad consensus. This was close to the forecast yesterday but quicker by about 12-18 hrs. Lead system in the Gulf showed continued good continuity and a blend sufficed, though the Canadian was perhaps too low with pressures via a few sfc lows. By next week, still forecast the sfc system to progress eastward into the Gulf as the triple point develops east of Kodiak, then continues swiftly eastward into the Panhandle. Ensembles and most models show a weaker system in the western Bering late in the period but with a large latitudinal spread. Favored the ensembles with some weighting of the ECMWF/GFS/Canadian. ...Weather Highlights/Threats... The Northeast Pacific/Gulf upper low Saturday will bring a surge of moisture into the southern mainland/Panhandle with significant precip totals possible at some locations depending on specifics of flow aloft, wind direction, and moisture levels. The fairly vigorous system tracking across the Bering Sea during the weekend into next week will likely bring a period of precipitation and winds, with effects reaching the mainland late weekend/early next week. Best potential for highest totals with this system will be near the southern coast but other locations may see meaningful precip as well. Expect below normal high temperatures across the northern and southern thirds of the mainland along with the Panhandle, while warmer readings versus normal will prevail over the central mainland, especially Saturday. Starting Sunday, the negative anomalies should expand and yield below normal highs over most of the state next week, but still with greatest negative anomalies over the far north and south. Clouds/precip should promote broader coverage of above normal min temps south of the Brooks Range. Fracasso 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 Hazards: - Heavy rain across portions of the Alaska Panhandle and mainland Alaska, Sat-Sun, Aug 1-Aug 2. 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