Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 158 PM EST Thu Feb 28 2019 Valid 12Z Mon Mar 04 2019 - 12Z Fri Mar 08 2019 ...Summary... A powerful storm track will hold in place from off eastern Asia northeastward into the Bering Sea over the next week. A mean trough aloft with embedded closed lows will continue to bring a series of deep lows into the Bering Sea that will move through the Aleutians toward western Alaska. System eastward motions remain limited by an amplified mid-upper level mean ridge built up and periodically rebuilt from the Gulf of AK up to the Interior and North Slope. ...Guidance and Predictability Assessment... A composite blend of reasonably well clustered guidance of the 12 UTC GFS/GEFS and 00 UTC ECMWF/ECMWF ensemble mean seems to offer a good starting point for the days 4-8 forecast, bolstering forecast confidence. The blend process acts to weed out the less predictable small scale detail and this forecast maintains good continuity with yesterdays WPC forecast suite. ...Weather Highlights and Hazards... The next in a series of deep storms will effect the Aleutians and Bering Sea this weekend then gradually lift and weaken over the western Bering Sea through early next week. Lead effects/frontal waves meanwhile work moisture and precipitation into southwest Alaska/Alaskan Peninsula and northward on the western periphery of the main upper ridge through western Alaska to the Arctic. Additional deep low threats are slated to reach the Aleutians and Bering Sea days 6-8 as less energetic systems energies/triple point developments attempt to work underneath into the Gulf of Alaska. Most of the rest of the state should remain mainly precipitation free under the mean upper ridge with mean temperatures above average through the medium range period. However, temperatures over the Panhandle will be slightly below average due to northeasterly/easterly flow out of Canada as a result of cold air leaked southwestward out of the Yukon. Bullet points from the WPC Days 3-7 Hazards chart: https://www.wpc.ncep.noaa.gov/threats/threats.php High significant wave heights/winds effecting coastal western AK, Mar 4-Mar 5. High winds across the Aleutians, Mar 3-Mar 4 and Mar 6-Mar 7. Schichtel WPC medium range Alaskan products including 500mb, surface fronts/pressures progs and sensible weather grids can 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