Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 558 PM EST Wed Feb 24 2021 Valid 12Z Sun Feb 28 2021 - 12Z Thu Mar 04 2021 ...Active Pattern from the Bering Sea/Aleutians to the Mainland/Gulf of Alaska... ...Overview and Guidance/Uncertainty Assessment... Upper pattern will be driven by a strong positive height anomaly moving off Hokkaido this weekend (+3 sigma 500mb heights per the ECMWF ensemble mean) will eventually translate eastward to the western Bering Sea by the middle of next week. This will favor downstream robust yet progressive troughing through the Bering into western/southwestern Alaska and then into the Gulf of Alaska in general west-to-east flow. With a rather defined wavelength, the models/ensembles were in good agreement overall. A blended mostly deterministic solution was preferred for the first few days of the period Sun-Tue (12Z GFS/ECMWF/Canadian/UKMET). This fit close to continuity as well with some expected timing differences. Increased ensemble weighting by later in the period as uncertainty increased in the Gulf with the digging upper trough and in the far western Bering with the next system. Ensemble consensus was better than average. ...Weather/Hazards Highlights... Exiting system on Sunday will provide locally heavy rain/snow to the Panhandle followed by more showery precipitation as the upper trough moves through. Progressive pattern may limit excessive amounts of precipitation. Next system will push swiftly through the Bering Sun-Mon with windy conditions and rain/snow along the Aleutians into southwestern Alaska. Models were in a bit better agreement on light to modest QPF into the Interior Mon into early Tue. Precipitation will then again focus on the Panhandle Tue-Wed as the upper trough digs into the Gulf. Temperatures will generally be below normal over much of the state next week, focused over the western/southwestern portion of the state. Fracasso Hazards: - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Sat-Mon, Feb 27-Mar 1. - High winds across portions of mainland Alaska and the Aleutians, Sun-Mon, Feb 28-Mar 1. 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