Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 700 PM EDT Wed Jun 14 2023 Valid 12Z Sun Jun 18 2023 - 12Z Thu Jun 22 2023 ...Overview... The upper pattern over the AK region/North Pacific will start out on Sunday still somewhat blocky allowing a deepened upper low to drift north towards the Aleutians. By Monday or Tuesday, the pattern may become a bit more transient with the upper low weakening and drifting East into the Gulf and the next system approaching the western Aleutians mid next week. Initial upper ridging over the mainland should break down in this pattern as troughing over northeast Russia rotates towards the North Slope region. ...Guidance Evaluation/Preferences... Model guidance is in good agreement on the overall synoptic/large-scale pattern through much of the period, and a blended solution of the deterministic guidance was used for days 4-6. After this time, some greater typical timing/strength differences began to arise, particuarly concerning the upper low moving into/towards the Gulf next week. The CMC and the ECMWF remain on the stronger/slower side of the guidance mainly due to maintaining a stronger ridge/bit more blocky pattern longer than the GFS. The ensemble means were also fairly progressive like the GFS, but seemed much too weak/washed out. Tried to strike a healthy balance between the GFS/ECMWF along with the ensemble means with the late period blend. This blend also helped smooth out differences with troughing over the Arctic which moves into the northern Mainland as well. The next system towards the Aleutians next Wednesday-Thursday shows very good agreement, though the GFS is a little bit faster than the ECMWF and CMC. Overall, this approach fits well with yesterdays WPC continuity, with some slowing of the system into the Gulf. ...Sensible Weather and Potential Hazards... Showers should increase over the central-eastern Aleutians and progress towards the east-northeast in advance of the extratropical system, but overall amounts still look to be light to modest at best. Showers may increase across the Southcentral as well, but mostly dependent on how close the low comes to the coast. Over the North Slope, showers will be more widespread, possibly locally heavy at times. Temperatures will be mostly below normal for much of the Mainland, but could be warmer than normal for some areas of the Eastern Interior and Southeast AK. Santorelli 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 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