Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 353 PM EDT Thu Aug 22 2019 Valid 12Z Mon Aug 26 2019 - 12Z Fri Aug 30 2019 An upper low is forecast to slowly move eastward through the Arctic as height falls push into the Bering Sea late next week. Upper ridging south of the Gulf/Panhandle will nudge eastward into southern British Columbia. This will favor stretched troughing from the Gulf of Alaska SSW into the Pacific where a series of relatively weak areas of low pressure will lift northeastward ahead of a a main baroclinic zone. The models/ensembles have trended more stretched (N-S) than yesterday, which would keep the more organized system well south of the Gulf but allow weaker ones to skirt the NW side of the upper ridge to the east. The GFS was in the minority with a more coherent system into the Gulf while the other deterministic models were more muted. However, all eventually focused any organized system south of 50N as the heights falls sink southward. To the north, main upper low will meander eastward with the possibility of a shortwave rotating around it, swinging through the North Slope. The 00Z ECMWF was a stronger representation of that idea. While plausible, a blend with the other guidance tempered its depth given the uncertainty at this time range. Heights will slowly rise later next week as the upper low wobbles into the Canadian Archipelago. In the Bering Sea, high pressure will dominate early in the week before a system moves eastward along the Aleutians. Deterministic models show a 1-2 reinforcement but regardless a slow but steady movement eastward is expected. 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 - Heavy rain across portions of the Alaska Panhandle, Sun-Mon, Aug 25-Aug 26. 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