Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 559 PM EDT Wed Mar 23 2022 Valid 12Z Sun Mar 27 2022 - 12Z Thu Mar 31 2022 ...Pattern Overview and Weather/Hazard Highlights... An amplifying upper trough south of the Aleutians and then entering the Gulf by early next week will sustain the development of a well organized surface low. This will approach the southeast Alaska mainland and then the eastern panhandle region with the potential for heavy coastal rain and mountain snow. A ridge axis builds northward across western Alaska and adjacent portions of the Bering and the Aleutians ahead of the next storm system approaching the Aleutians by the middle of next week, with more rain and windy conditions likely. The developing Gulf low for early next week will likely have gusty winds, moderate to heavy rain, mountain snow, and even high waves across the southeast panhandle region for next Monday and into Wednesday. Strong onshore flow that is orthogonal to the terrain will enhance precipitation totals for the windward areas. In terms of temperatures, most of the mainland should enjoy readings above average through the weekend, followed by a return to seasonal to below average readings for some areas through next Wednesday. It will remain quite cold for locations north of the Brooks Range. ...Guidance/Predictability Assessment... The 12Z UKMET/CMC/ECMWF guidance suite is in good agreement on the overall synoptic scale pattern through the beginning of next week. The past few runs of the GFS have been consistently displaced well to the southwest of the model consensus regarding the strong Gulf low that will be affecting the southern coastal areas, and is also not supported by its own GEFS ensemble mean. This is a result of an upper trough axis that is displaced to the west of the model/ensemble consensus. In addition, the GFS becomes much more amplified with the next storm system emerging from the Bering Sea/Aleutians region by next Wednesday/Thursday. The CMC/ECMWF/UKMET and the ensemble means all suggest a solution closer to the south-central Alaska coast for the Gulf of Alaska system, and thus a non-GFS blend will be preferred. There is a gradual increase in the ensemble means for the second half of the forecast period to account for normal levels of increasing uncertainty. Hamrick Hazards: - Heavy precipitation across portions of the Alaska Panhandle, Mon-Wed, Mar 28-Mar 30. 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