Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Sun Jul 14 2019 Valid 12Z Thu Jul 18 2019 - 12Z Mon Jul 22 2019 An upper low slowly moving eastward through the Arctic Ocean will be the main focus for the interior/northern areas of the 49th state. This will gradually introduce lower heights to much of the mainland north of Southcentral as heights build through the Bering Sea. An upper low will exit the Panhandle Thursday but lingering troughing will be maintained south of the Gulf. The models/ensembles largely handle this evolution well but detail differences plagued the deterministic models in recent runs. However, the 12Z GFS and 00Z ECMWF offered enough compatibility to be used in the blend with the 00Z ECMWF ensemble mean. The recent GEFS means have been less consistent across the north with the incoming troughing, flattened by spread in the members. Given the relative stability and trend (to more troughing) in the ECMWF ensemble mean, a blend with the GFS/ECMWF offered a good starting point. To the south, GFS runs from 24 hrs ago have abandoned the more robust surface wave development late next week but the 12Z GFS again showed such development early next week. By then, this may be plausible given the pattern shift but was only depicted as a weak wave well south of the region. Pattern favors near to above average temperatures in offshore flow early in the period over Southcentral but near/below average across the North Slope and Panhandle due to lowering heights (north) and precipitation (both areas). Though the heaviest precipitation may be over the Panhandle, the North Slope could see the heaviest relative precipitation given the lower climo values. Elsewhere, the Alaska Range will see scattered showers with enhancement as the baroclinic zone approaches. Fracasso 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 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