Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 604 PM EST Sun Feb 09 2020 Valid 12Z Thu Feb 13 2020 - 12Z Mon Feb 17 2020 ...Guidance and Uncertainty Assessment... The 12 UTC ECMWF has trended toward the 12 UTC GFS and 12 UTC GEFS/ECMWF ensemble means Thursday-Saturday, albeit with some lingering timing differences. The 12 UTC GFS though offers a more consistent solution that is better clustered with the ensemble means. Accordingly and after collaboration with the local WFO offices, the forecast starting point for the WPC Alaskan product suite was primarily derived from a blend of the reasonably compatable guidance from the 12 UTC GFS and GEFS/ECMWF ensemble means along with the 19 UTC National Blend of Models. Forecaster adjustments were applied to add increased detail consistent with individual weather feature predictability and support, especially as per the deepening of offshore lows that were artificially weakened by the blend process. This acts to maintain good WPC continuity as compared to yesterday. ...Weather Pattern and Hazards Highlights... The mid-upper flow pattern later this week will feature a mean trough/low over the Aleutians/Bering Sea. This will support a series of potentially deep storms to focus a threat of heavy precipitation/winds/seas across the Aleutians/Bering Sea. This is especiallty the case with a very deep/threatening low Thu-Fri. A weakening downstream ridge will shift from Southwest Alaska to southern Alaska Thu/Fri as an amplified and quite wet lead upper trough/low works over the Southeast Panhandle. Frigid air settled over the Interior now moderates in guidance more gradually late week into next week as guidance now rebuilds Arctic stream upper troughing back over the region. Pattern de-amplification with time over the Gulf of Alaska will allow periods of precipitation spread into the Alaska Peninsula/Southwest Alaska and southern Alaska. Active flow over the Gulf of Alaska will support several organzied low pressure systems that especially offer the threat for periods of heavy precipitation over the Southeast Panhandle. Schichtel 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