Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 756 PM EDT Wed May 22 2024 Valid 12Z Sun May 26 2024 - 12Z Thu May 30 2024 ...Overview... An upper low over the northeastern Pacific early next week will spin down as it slowly moves east. Meanwhile there is some increasing model signal for a small upper low to track from near the northwest to southwest Mainland. As the week progresses, troughing/energy are likely to spill east into the Bering Sea and Aleutians but with low confidence in the details. ...Guidance Evaluation and Preferences... Model guidance is agreeable with the large upper low and associated surface low over the northeast Pacific gradually drifting east while weakening Sunday through midweek. Meanwhile, a small upper low is showing a bit more consistency among recent guidance. By Sunday most models have the feature dropped toward the Bering Strait and vicinity, with the exception of the CMC that meandered it north of the North Slope. A general drop south is likely through Monday and Tuesday, but beyond that models diverge with where that low goes, which is dependent on the upstream features. Model spread increases quite a bit upstream as larger scale upper troughing/possible lows and vorticity maxima tracking eastward. The ECMWF for example pushes some energy east across the Aleutians Monday-Tuesday while maintaining most energy to the west near or west of Kamchatka. GFS runs on the other hand consolidate into one upper low steadily progressing eastward across the Aleutians Tuesday-Thursday. There is low confidence on how this will play out but a more troughy pattern is likely over the Bering Sea/Aleutians in general. The WPC forecast used a model blend heavily favoring GFS runs and the ECMWF early in the forecast. Gradually progressed to include more ensemble means to just over half by Days 7-8 amid the increasing spread and uncertainty. ...Weather/Hazards Highlights... Rain amounts should be modest through the period overall. Southern parts of the Panhandle may see a relative maximum as the northeast Pacific upper low directs moisture there. Light to moderate lower elevation rain and higher elevation snow in the southeastern quadrant of the Mainland to the Alaska Range in particular, with some light amounts farther west, and by midweek farther north into the Interior. Energies and possible lows/frontal systems pushing through the Aleutians to Alaska Peninsula could lead to periodic precipitation as well. There is some possibility for enhanced winds across western Alaska early in the week but do not look too strong. Interior Alaska is likely to see the mildest temperatures across the state, with highs generally in the 60s to nearing 70 as the week progresses with a warming trend. The Brooks Range to North Slope should also see temperatures warm with time, from around to above the freezing mark for highs in the Arctic Coast communities. For the southern coast, temperatures at least for highs are forecast to stay below normal, with 40s and 50s for the most part. Tate 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