Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 226 PM EDT Thu Jun 28 2018 Valid 12Z Mon Jul 02 2018 - 12Z Fri Jul 06 2018 An upper low and associated trough is forecast to drift east northeast into the Chukchi Sea/Arctic Ocean early next week. The models and ensembles still differ on timing/amplitude of the upper tough or embedded closed low. The 00z ECMWF and 06-12z GFS all develop a closed low near the northeast coast of Alaska, with radically different timing and tracks. The 12z GFS made a major change to move this low straight south Wed-Thu 05 Jul to near the southeast coast 12z Fri 06 July. The models are trending towards creating height falls in southeast AK and coastal waters as the massive anticyclone over the north Pacific retrogrades west. In the wake of the departure of the upper trough moving towards Vancouver Island Mon night-Tue, heights slowly build west to east across the lower to mid Aleutians, with the positively tilted ridge extending northeast across interior Alaska, and then further east into the Yukon. The above normal heights and temperatures favor a pattern of above normal temperatures in the early to middle portions of next week across southern Alaska, including in the Aleutians. The 12z GFS was along in building this ridge north to the north coast 00z Thu 05 Jul. A closed low moves north from the north Pacific across the lower Aleutians into the western Bering Sea in the middle of next week. Minor timing and intensity differences led to a consensus based approach to resolve the differences. The low comes into confluent flow and gradually shears with time, resulting in low pressure at the surface filling in the Bering Sea. Manual progs blended the 06z GEFS Mean and 00z ECMWF ensemble mean with less weight on the volatile operational 00z ECMWF and/or 12z GFS. Petersen 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 www.wpc.ncep.noaa.gov/alaska/akmedr.shtml http://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html