Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 622 PM EDT Thu May 13 2021 Valid 12Z Mon May 17 2021 - 12Z Fri May 21 2021 ...Overview... Rather unpredictable smaller wavelength pattern will mostly feature troughing along 50N and far NW Alaska as weak upper ridging meanders over the Interior and NW Canada. With low pressure mostly over the northern Pacific into the Gulf, appreciable precipitation will be limited to the Panhandle and Aleutians. ...Guidance/Predictability Assessment... The models have really been struggling with how the systems evolve out of the western/central Pacific next week, and continue to shift with each cycle. Even the ensemble means have been susceptible to changes in timing, though can still show agreement with each other. Felt a broad consensus was appropriate given the less-than-normal predictability (though probably par for the pattern) among the 12Z GFS/ECMWF/Canadian to start (with the GEFS/ECMWF ensemble means), transitioning to a mostly ensemble mean blend with only some details from the 12Z ECMWF. Preferred to keep the system next Thu just south of the Aleutians based on the ensemble overlap rather than have it lift into the Bering Sea. ...Weather/Threats Highlights... Weak troughing over the mainland into the Gulf will promote scattered showers across the Interior/North Slope into the Panhandle early in the week. A more defined system may approach the Aleutians around the middle of next week (lead system may dissipate around Wednesday) with light rain for the island chain. Temperatures will be within several degrees of normal over much of the state, but near to below normal over the Panhandle. Fracasso Hazards: No significant hazards are expected over Alaska during this forecast period. 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