Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 628 PM EDT Tue Jun 13 2023 Valid 12Z Sat Jun 17 2023 - 12Z Wed Jun 21 2023 ...Overview... Upper pattern over the high latitudes/North Pacific will feature a meandering upper low centered over northeastern Russia/Wrangel Island with transient ridging moving through the Gulf of Alaska. The remnants of former Typhoon Guchol will approach the AKPen early next week in a weakened form and turn eastward across the Gulf as modest ridging noses across the eastern AK/Canadian border. A slow trend toward more typical temperatures for mid-June is forecast, but it will be a slow go. ...Guidance Evaluation/Preferences... Model guidance is in good agreement overall with the shift in the pattern, and a blended solution was utilized with a couple exceptions. The most disagreement lied in the evolution of the mean upper low over northeastern Russia and any residual areas of vorticity on its southeast side. The consensus has been to keep the center generally west of the Bering Strait though could not rule out some leaky height falls into the southwest mainland. The approach of ex-Guchol quickened just a bit from 24 hours ago, but the guidance still agrees on a maximum strength well away from even the Aleutians let along the mainland/coastal Southcentral. Continuity and the ensemble consensus tracks the extratropical system on a path just southeast of the central Aleutians/AKPen/Kodiak like the 12Z ECMWF/Canadian. The 12Z GFS was on the far western side of the spread and was discounted. The transient ridging in the Gulf should be of insufficient strength to force a more northerly track of the system, thus allowing the low to turn easterly across the Gulf around the middle of next week. Both the 12Z GEFS mean and 00Z ECMWF ensemble mean were quite agreeable through the forecast period. ...Sensible Weather and Potential Hazards... Exiting upper low over the Gulf will maintain some showers over the Panhandle to start the period Saturday, but will diminish as upper ridging moves in by late Sunday. At that time, showers will increase over the central Aleutians and progress northeastward in advance of the mature extratropical system but overall amounts will be light to modest at best. Showers and some steadier light rain will continue to expand across Southcentral early next week as the low makes its closest approach near Kodiak before turning east. Over the interior to the North Slope, showers will be prevalent especially during daytime heating with upper level temperatures still chilly. Temperatures will be near to below normal to start the period for much of the mainland but near to slightly above normal for some areas of the eastern interior. Fracasso 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