Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 625 PM EST Tue Nov 26 2019 Valid 12Z Sat Nov 30 2019 - 12Z Wed Dec 04 2019 Upper troughing will slowly migrate out of the western Bering Sea this weekend into mainland Alaska, with a ridging building into the Bering behind it. The models/ensembles continue to shift with embedded system timing/track/depth, but overall have maintained good synoptic agreement. Overall, the 12Z ECMWF represented the best deterministic solution near its 00Z ensemble mean, followed by the UKMET/Canadian in most places and also the 12Z GFS. Trended much more toward the ensemble means, in particular the ECMWF ensemble mean, by next week as incoming systems showed less predictability on the back side of the upper low. System of interest will approach the AKPEN early Sunday then cross ENS over Kodiak into Prince William Sound per the forecast. The GFS lied to the east while the UKMET was to the west (Canadian well to the northwest), leaving the 12Z ECMWF in the middle near its ensemble mean. Though the GEFS mean was farther northwest as well, opted to stay closer to continuity which seemed to be near the broad mid-point. This should bring a period of modest to locally heavy coastal rain and inland/mountain snow from the Kenai eastward to the Panhandle Mon-Tue before exiting by Wednesday. To the north, GFS/GEFS continued to show a folded upper ridge atop the Bering upper low while the other guidance kept a NW-SE upper ridge axis (and weak closed upper high) north of Utqiagvik. GFS may be trending a bit toward the others so it was not necessarily implausible. Regardless, all models show this feature slipping westward into the East Siberian Sea as lower heights encroach on the west coast of Alaska. 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 Hazard: - Heavy precipitation across portions of mainland Alaska, Fri, Nov 29. - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Mon-Tue, Dec 2-Dec 3. 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