Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 324 PM EST Sat Feb 09 2019 Valid 12Z Wed Feb 13 2019 - 12Z Sun Feb 17 2019 ...Guidance Assessment... Latest GFS/ECMWF and GEFS/ECMWF ensemble mean solutions overall seem to cluster reasonably well for much of the next week at medium to larger scales and the WPC Alaskan medium range forecast product suite was primarily derived from a composite blend. However, applied increased blend weighting to the GEFS/ECMWF ensemble means to keep max WPC continuity and offer system detail consistent in a pattern with slightly better than normal predictability. Manual adjustments were also applied to depict deepened offshore low pressure centers consistent with favorable support aloft in continuation of recently stormy flow. ...Pattern and Weather/Threats Highlights... A lead low will exit the North Slope/interior to the Arctic midweek. System passage will act to bring height falls from the North Slope and interior to the Gulf of Alaska, temporarilty replacing early week upper ridging. Low/frontal system development slides underneath to the northern and southeastern Gulf of Alaska Wed-Thu. Guidance has trended stronger with this system set to undercut a frontal drape pushed just offshore southern/southeastern Alaska. Models and ensembles show a main upper ridge may rebuild later week with a mean axis over the western half of the mainland. Reamplification allows transition toward a pattern that will tend to force an upstream series of potentially deep and stormy low pressure systems more over the western half of the Bering Sea/Aleutians. This occurs as high pressure builds over the mainland and northwest Canada, but expect storm activity may be able to work more back toward western/southwestern Alaska/AKpen next weekend as the shielding ridge nudges eastward. Schichtel WPC medium range Alaskan products including 500mb, surface fronts/pressures progs and sensible weather grids can be found at: http://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif http://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml http://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html