Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 637 PM EDT Wed May 12 2021 Valid 12Z Sun May 16 2021 - 12Z Thu May 20 2021 ...Overview... Blocky flow will transition toward troughing centered over the Bering Sea around the middle of next week, but with uncertainty in how that evolves. 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 deterministic models were in mostly good agreement to start the period, but then diverged by next Tuesday due to the multiple weaker streams around Alaska. Trend has been for a bit less merging of northern/southern shortwaves just south of the Aleutians, and a slower pace overall. With so much uncertainty by next Tue-Thu, used a majority ensemble mean blend (12Z GEFS and 00Z ECMWF ensemble mean) with some details from the 12Z GFS that paired best with the ensemble consensus vs the ECMWF or Canadian. Confidence was lower than average due to poorer-than-normal run-to-run consistency even in the ensembles. ...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 on Tuesday) 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