Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 534 PM EDT Sat Mar 23 2024 Valid 12Z Wed Mar 27 2024 - 12Z Sun Mar 31 2024 ...Major North Pacific to Bering Sea Storm increasingly likely to threaten Alaska late next week and weekend... ...Guidance Evaluation and Preferences... Run to run guidance continuity has improved significantly and seemingly reasonably, bolstering forecast confidence to above normal levels for both the pattern evolution and the main weather systems in increasingly active and dynamic flow next week. This includes the development and approach of a potentially major North Pacific to Bering Sea Storm for later next week/weekend as powered by a strong East Asian jet. A composite of similar 12 UTC GFS/ECMWF/UKMET/Canadian guidance provides good detail through next midweek. The ensemble means then provide a solid and more consistent depiction of the main systems onward into next weekend, especially when aligned with applied manual adjustments to ensure significant surface system depth consistent with favorable upper support. ...Pattern Overview and Weather/Hazards Highlights... A closed low with short range origin dug from the Arctic should meander and slower weaken over the Bering Sea through later next week while slowly losing influence, blocked to the west of an ambient downstream upper ridge lingering into the eastern Mainland. This pattern may favor enhanced winds around the low along with light to moderate western/southwestern mainland snow potential as locally aided by uncertain interaction/lifting moisture from the Pacific stream. Meanwhile, there is quite an emerging guidance signal to monitor for subsequent development and approach of amplified closed upper trough/low Pacific stream energy and associated deep surface low pressure system toward the Aleutians by later next week that would offer turbulent maritime conditions and swirling winds and rains. This potentially deep/major storm is now likely to track northeastward into the southern Bering Sea and become increasingly impactful for coastal/wind/heavy precipitation threats for western/Southwest Alaska and into the Interior as well as downstream/underneath with energy transference into the Gulf of Alaska and inland with lead moisture influx for the Alaska Peninsula/Kodiak Island and then SouthCentral to Southeast Alaska next weekend. Schichtel 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