Alaska Extended Forecast Discussion National Weather Service College Park MD 737 PM EDT Thu May 8 2025 Valid 12Z Mon 12 May 2025 - 12Z Fri 16 May 2025 ...Synoptic Overview... The synoptic pattern across Alaska for the upcoming workweek is about as normal/ordinary as it gets for the state. If there were a "default" weather pattern for Alaska this one would be it. The week starts off on Monday with a low over the eastern Bering, near the Pribilofs. The low's occluded front will extend across the Alaska Peninsula and Kodiak and south into the Pacific Monday morning. Meanwhile, rain will overspread southwest Alaska as the occluded front wraps around the low. It will be vertically stacked with an upper level low by Monday. The low will then turn westward, as the associated precipitation with its front moves east into Southcentral and the central Gulf. By Monday night the front will move into the northern Panhandle and portions of the interior, as rain continues across much of Southcentral. The front will shear apart and dissipate over the many mountains of southeastern Alaska, the Panhandle and the Yukon on Tuesday, resulting in diminishing rainfall rates, but the associated cloud cover will persist for much longer. Meanwhile a second North Pacific low will move into the central Aleutians, caught up in the upper level low and trough the remains parked over the eastern Bering. This low will merge with the dissipating and stationary first low, allowing it to persist into late week. Meanwhile the energy that continues with the low over the north Pacific may briefly spin up a triple point low in the far western Gulf, between the Shumagins and Kodiak Island, but most of the guidance, notably the 12Z EC have backed off on this low becoming the dominant low, instead having it dissipate or merge back into the occluded front, which proceeds into the Gulf Coast from Kodiak through the Panhandle on Thursday. Associated rainfall will persist, especially through the Panhandle into Friday, but it's not expected to be hazardous. Meanwhile the merged low over the eastern Bering will continue weakening as the upper level trough also weakens and spreads over much of mainland Alaska. Across northern Alaska, a very steady state pattern will persist through the workweek, with persistent onshore northerly flow off the Arctic Ocean keeping the weather tranquil, if cold, across the North Slope due to cold air damming. This is due to an Arctic high that will remain parked well north of the coast. This same high will keep gusty north winds through the Bering Strait, which will also favor cooler temperatures. ...Guidance Evaluation and Preferences... As is very typical, the guidance is in good agreement at the start of the period Day 4/Monday, then gradually becomes more uncertain through the week. Since the deterministic guidance offers much better resolution of smaller details of the forecast, the general agreement supported the use of the deterministics through Wednesday. With less agreement for the end of the week, particularly how any triple point lows in the Gulf emanating from the newly merged low over the eastern Bering, ensemble guidance was favored by the end of the week. The 12Z GFS was the preferred of the deterministics, since it was the middle ground solution of the CMC and EC. An even use of the ensembles was used late in the period, capturing the overall broad upper level trough that persists over much of mainland Alaska. ...Weather/Hazards Highlights... With a very common and seasonal pattern setting up across Alaska, there are no hazardous conditions expected. Gales will be likely south of the low over the eastern Bering on Monday between the center near the Pribilofs and the Aleutians/Alaska Peninsula. The low will draw a southerly fetch of moist, Pacific flow into the south side of the Alaska Peninsula and Kodiak, which may support periods of heavy rain Monday and Tuesday, but nothing out of the ordinary. && Wegman 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