Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 213 PM EST Tue Feb 20 2018 Valid 12Z Sat Feb 24 2018 - 12Z Wed Feb 28 2018 Ensembles over the high latitudes show a westward moving upper low along 75-80N out of the Canadian archipelago while a persistent upper high meanders around 35N/150W. The flow in between these two anomaly centers (though the upper high is much stronger than the low from a standardized anomaly perspective) will remain progressive with distinct waves moving eastward along 55N. The deterministic models (at least the 06Z GFS and 00Z ECMWF) offered good clustering with each other and their ensemble means through the weekend as one front moves into SW Alaska and takes its triple point low eastward through the Gulf (though the ECMWF was a bit quicker than the rest). Next system on its heels will move into the Bering Sea and push its cold front and triple point low eastward through the Gulf early next week (Mon-Tue) as it rides up and over the ridge. By then, question becomes how much ridging will remain in place or be allowed to briefly relax as the shortwave passes by. ECMWF ensembles generally allowed the heights to rise and fall with each wave while the GEFS members did not allow heights to fall as much next week. This was likely due to the last system of interest moving into the western Bering Sea next Wednesday -- the GEFS members were quicker than the ECMWF ensembles. Though the upper pattern over Alaska does not necessarily support a slower solution, the western Pacific may also be in between an upper low over northeastern Russia and subtropical ridging around 140-150E, which could support a deeper system around 170E. Opted to mostly split the difference between the ECMWF ensemble mean and GEFS mean by next Tue/Wed (60/40) pending future model cycles. Temperatures will be near to above average over most of the interior with well above average values in NW Alaska. Southeastern Alaska will be near to below average with sfc high pressure over NW Canada. Precipitation will focus mostly in SW Alaska and over the Aleutians but with mostly light to modest amounts over the period due to the progressive flow. Fracasso