Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 600 PM EDT Thu Oct 01 2020 Valid 12Z Mon Oct 05 2020 - 12Z Fri Oct 09 2020 ...Overview and Guidance/Predictability Assessment... Increasingly progressive pattern remains well-advertised by the guidance, with a strong system plowing through the Bering Sea next Tue-Thu. The 12Z guidance was fairly closely-clustered to start as a departing system moves through the Panhandle early Mon. Trend was a bit slower, so the front was slowed a bit as well but the parent low position nearing Prince William Sound remained on track. 12Z GFS/ECMWF again offered good agreement and formed the majority of the blend. For next Tue-Fri, focus turned to the Bering Sea. Trend continued to be just a bit quicker, giving credence to the ECMWF ensembles from several days ago (seemingly too quick compared to the rest of the guidance). Latitudinal spread among the guidance between about 57-62N suggested a middle ground track near 60N toward the central Bering Sea (12Z GFS was most reasonable here) before the system likely sinks southeastward across the AKPEN as triple point redevelopment takes place just southwest of Kodiak by early Thu. Again the 12Z GFS/ECMWF were remarkably close, but opted to blend in about 40% ensemble mean weighting to temper the system for now. That low should push into the Gulf as the old parent low slowly weakens in the Bering. Better than average deterministic/ensemble agreement led to above average confidence. ...Weather/Threats Highlights... Lingering modest rain (perhaps locally heavy) on Monday will diminish over parts of southern coastal areas to the Panhandle. Some drying is forecast over the mainland Tue-Wed as height rise in advance of the Bering system. Rainfall will increase over the Aleutians late Tue into Wed as the cold front moves through, but progressive flow should limit heavier rainfall. Once the triple point redevelops east of the Aleutians, heavier rain may wrap around the new low into Kodiak, southeastern Kenai, and the west side of Cook Inlet. Temperatures are forecast to be near to well above normal over most of the mainland, especially north of the Alaska Range. Near to below normal max temperatures are forecast for the Aleutians, across portions of Southcentral, and over the Panhandle. Min temperatures will be closer to normal over southern areas to well above normal across northern areas. 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 precipitation across portions of the Alaska Panhandle and mainland Alaska, Sun-Mon, Oct 4-Oct 5. 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