Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 712 PM EDT Fri Sep 13 2024 Valid 12Z Tue Sep 17 2024 - 12Z Sat Sep 21 2024 ...Bering Sea Storm to impact the Aleutians and Southwest Alaska/Alaska Peninsula early next week... ...Guidance Evaluation/Preferences... Guidance continues to herald a protracted period of highly energetic and progressive flow with a series of potent storms to impact Alaska over the next week. A composite of now reasonably well clustered guidance of the 12 UTC GFS/ECMWF/UKMET/Canadian offers good system detail consistent with above normal system predictability and WPC product continuity Tuesday into Thursday. Prefer a switch to best compatible ensemble means at longer time frames as predictability lowers closer to normal amid growing forecast spread. ...Weather/Hazards Highlights... Lead storm energy digging through and exiting the eastern Gulf of Alaska into Tuesday will support lingering unsettled weather to include some enhanced rains/winds/waves over the Gulf of Alaska and inland across the far southern Panhandle. Upstream, forecast confidence continues to rise through above average levels regarding the details for yet another major storm slated through the early through middle part of next week. Expect a deepened/potent low track through the Aleutians and southern Bering Sea into with earnest Southwest Alaska will also with downstream energy transfer reform over the northern Gulf of Alaska and track near/offshore the Alaskan southern tier, eventually and actively crossing Southeast Alaska later Wednesday into Thursday. This would focus the majority of precipitation to the southwestern mainland and southern to southeastern Alaska. This storm will again also produce widespread maritime threats of high winds and waves. Onshore, the WPC Hazards Outlook depicts an associated risk of high winds and coastal impacts from the Aleutians to Southwest Alaska and the Alaska Peninsula given dynamic system strength and speed. The pattern seems to remain favorable for additional storm systems upstream in this flow. Predictability lowers to average for developments and tracking, most likely from the southern Bering Sea/Aleutians/northern Pacific into the Gulf of Alaska/Alaska southern tier next Friday/Saturday to monitor. Meanwhile to the north, lingering low pressure centering over the Interior along with the uncertain passage and digging of shortwave energies aloft over the mainland may support persistence of scattered light precipitation into next week in the wake of a highly energetic leading short range storm. Activity on the northern periphery of the next main Bering Sea storm through next midweek may also lead to some locally/terrain enhanced gusty winds and precipitation. 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