Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 624 PM EDT Fri May 13 2022 Valid 12Z Tue May 17 2022 - 12Z Sat May 21 2022 ...Overview and Guidance/Predictability Assessment... A rather amplified upper level pattern is expected across the Alaska domain for next week, with a strong upper ridge and potentially closed high over the Bering remaining nearly anchored in place with a potential rex block developing by the end of the week. Some upper level troughing will likely be in place across the Arctic Coast region. At the surface, a low pressure system over the Gulf will gradually weaken and move inland early next week, while a broader, elongated low develops south of the Bering high. The 12Z model guidance suite is in good synoptic scale agreement across much Alaska and vicinity through about Thursday. One of the main differences early in the extended period is a weaker solution with the UKMET/GFS regarding the extent of the upper ridge across the Aleutians/Bering, and the 12Z GFS stronger with the upper low approaching the British Columbia Coast. By Friday night and into next Saturday, there is still good consensus for a southeast-northwest oriented ridge axis across the southwestern mainland, although model differences are greater across the Arctic region with the GFS generally stronger with a trough north of the Yukon. The WPC forecast was primarily derived from a multi-deterministic model blend through early Thursday, with slightly greater weighting towards the ECMWF/CMC solutions, and then a gradual increase in the GEFS/ECENS for Friday and Saturday whilst still maintaining some of the deterministic guidance. ...Weather and Hazard Highlights... There are chances for modest precipitation across portions of mainland Alaska into next week as upper disturbances/surface fronts work across the area, but the main threat should remain for any river flooding associated with snow melt and ice jams. Offshore to the south, a well organized upper low/trough and associated surface system lingering over the eastern Gulf of Alaska will favor a periodic focus for light to moderate terrain enhanced precipitation over Southeast Alaska/Panhandle into early-mid next week, but otherwise a rather benign precipitation pattern for the state. Temperatures across much of the mainland for earlt next week are likely to remain below normal, with the greatest anomalies for northern Alaska as a deeper shortwave drops in through the region. Temperatures are forecast to moderate going into the middle to end of the week, with parts of western Alaska and the Peninsula likely having above normal highs as the Bering Sea ridge slowly works inland next week. Hamrick Hazards: - Flooding possible across portions of mainland Alaska, Mon-Fri, May 16-May 20. Additional 3-7 Day Hazard Information can be found on the WPC medium range hazards outlook 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