Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 639 PM EST Fri Feb 14 2020 Valid 12Z Tue Feb 18 2020 - 12Z Sat Feb 22 2020 Strong positive height anomalies south of Kamchatka in the subtropical Pacific (~25N/140E) will favor troughing in the Bering Sea and western Alaska next week. The 12Z models were in good agreement overall with fairly well-defined frontal systems moving through the North Pacific and Gulf into the mainland/Panhandle. This may bring a substantial system into Southwestern/Southcentral areas from the short term into the medium range early in the week, followed by another system Thursday-Friday. The active pattern may continued into and beyond next weekend. To start, models mostly agree on taking a parent low into Bristol Bay toward Nunivak Island with its wavy front southward into the Pacific. This may carry a sfc wave northward toward into the Kenai Peninsula late Tue into early Wed before continuing eastward. Next system showed a bit less agreement as it slides along or just south of the Aleutians Wed-Thu. The 12Z (and prior) GFS took it to the north of the eastern Aleutians but the majority kept it just to the south, which was preferred. That low may shift into the far NW Gulf near the Kenai Peninsula by early Fri with its front into the Panhandle. Progressive pattern should keep these systems moving and limit any sfc wave development. Last system may affect the western Aleutians by next Saturday with better than average agreement between the models and ensemble means. Temperatures may briefly rise around the occlusion Tue before trending back toward below average as colder air is dragged down from the north behind the lead and second system. The Panhandle should see nearer to average temperatures with mainly westerly onshore flow, but a nearly daily chance of precipitation. Highest rain/snow totals are likely over Southcentral, on the west side of Cook Inlet and southeast side of the Kenai Peninsula across Prince William Sound to Yakutat. 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 southern mainland Alaska, Tue-Fri, Feb 18-Feb 21. - Heavy snow across portions of southern mainland Alaska, Mon-Thu, Feb 17-Feb 20. - Much below normal temperatures across portions of mainland Alaska, Mon, Feb 17 and Thu-Fri, Feb 20-Feb 21. 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