Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 306 PM EST Tue Nov 05 2019 Valid 12Z Sat Nov 09 2019 - 12Z Wed Nov 13 2019 Most model and ensemble guidance shows a large scale pattern featuring varying degrees of mean ridging aligned from near the British Columbia coast north-northwest through the mainland while troughing (with one or more embedded closed lows) migrates across the southern Bering Sea/Aleutians/North Pacific. The gradient between these two features should gradually tighten and shear out or eject in some fashion the initial energy over the east-central Pacific and southern Bering. Over higher latitudes by next Tue-Wed there is some clustering toward the idea of cyclonic flow settling over the Arctic/Canadian Archipelago with an associated cold front reaching the northern mainland. Models and ensemble members display little meaningful clustering for individual lows over the northeastern Pacific/Gulf of Alaska for most of the period, keeping detail confidence quite low. There is a somewhat better signal for a significant low pressure system over the North Pacific, albeit with typical timing/track differences for the time frame involved. One big question mark here is to what extent Super Typhoon Halong plays a role--with very poor agreement on that aspect. Overall prefer a model/mean compromise, with the ECMWF mean likely too fast given system strength. ECMWF runs had been oscillating but the new 12Z run has maintained a more western path similar to the past couple 00Z runs. The 12Z GFS is even farther westward. At higher latitudes, latest GFS runs have joined recent ECMWF runs in bringing an Arctic upper low to the northeast of the mainland. The ensemble means keep the feature farther northeastward but still show enough cyclonic flow to bring a cold front into the North Slope region. Based on the current array of guidance and continuity the forecast blend started with an even weight of the 00Z GFS/ECMWF and NAEFS/ECMWF means through the period. The NAEFS mean was generally stronger than the 06Z GEFS mean with important features. This blend and subsequent manual adjustment represented the most agreeable aspects of the overall pattern while providing some degree of embedded detail and downplaying other less confident ideas. For example recent ensemble mean trends toward a modestly stronger mean ridge aloft question the degree to which CMC and perhaps even to some extent ECMWF runs have been bringing energy into the mean ridge early next week. Expect highest precipitation totals for the period to be along the southern coast and Panhandle with meaningful amounts also across the Aleutians. Strong winds may accompany the potential North Pacific storm early-mid week. Rausch 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 - Much above normal temperatures across portions of northern Alaska, Sun-Mon, Nov 10-Nov 11. - Much above normal temperatures along the coastal plains of northern Alaska, Sun-Tue, Nov 10-Nov 12. 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