Alaska Extended Forecast Discussion National Weather Service College Park MD 727 PM EDT Wed Oct 1 2025 Valid 12Z Sun 05 Oct 2025 - 12Z Thu 09 Oct 2025 ...Synoptic Overview... The upper level pattern over Alaska will remain amplified through the period (Sunday-Thursday) featuring a series of strong surface lows and heavy precipitation potential. This weekend, deep troughing, anchored by an upper low over eastern Russia, will advance eastward through Alaska supporting a period of heavy rainfall this weekend into early next week. Behind this, amplified ridging will briefly build over the Mainland by next Wednesday as a deepening low pressure system crosses the Western Aleutians into the Bering Sea. The associated surface low will lift northeastward through the Bering sending a cold front into western Alaska Wednesday or Thursday. Very gusty winds and moderate to heavy precipitation may accompany this system. ...Guidance Evaluation and Preferences... Models and ensembles remain in generally good agreement with the initial deep troughing shifting through Alaska this weekend. There are some differences in the exact location of the surface low crossing from the Bering Sea into the Chukchi Sea, but a general compromise of the guidance resulted in a good starting point. The latest ECMWF came in slightly faster than its prior 00z run and the GFS is notably slower than the consensus with the cold front through the Gulf. After this system, the next system will move across the western Aleutians into the Bering Sea early next week. There is still a fair bit of spread on how deep the low actually gets, but deterministic guidance shows a low into the 960s mb while some ensemble members are even lower. The GFS is a bit on the east side of the forecast track while the ECMWF is in the middle and serves as a good basis for the late period forecast. This low should track northward through the Bering Sea, on a similar track to the initial weekend low. At least right now, much of the guidance keeps the actual low track west of the West Coast, but associated hazards will extend inland. The WPC forecast for tonight was based on the ECMWF with the CMC and UKMET the first half of the period. By days 5-7, used increasing weighting of the ensemble means which helped smooth out some of the smaller scale differences. ...Weather/Hazards Highlights... The first Bering Sea low in the northern Bering will continue to bring some gusty wind and coastal flooding threat across parts of the western mainland with with moderate precipitation that may reach inland areas of the western and central Interior north to the Brooks Range as well. As the upper- wave/surface frontal system progress eastward over the Gulf later this weekend and into early next week, heavy rain will be possible at the lower elevations at times with upslope flow into the coastal ranges. This will especially be the case around Prince William Sound and east to Yakutat where several inches of rainfall can be expected. Higher elevation snow will also impact the mountains but freezing levels will remain high enough that the passes will not be affected. A heavy rain hazard remains for Sunday-Monday on the WPC Hazards chart. The next system crossing the far western Aleutians will bring increasing precipitation by next week for parts of the Aleutians and gusty winds. Expect strong to Gale force winds over the Bering Sea, with some concern particularly for St. Lawrence Island. Gusty winds and coastal flooding concerns will need to be monitored for parts of the Western coast with too much uncertainty on the exact placement of the low for any highlighted hazard areas. Temperatures looks to remain near to above normal through the period for nearly all of the state. Daytime highs could be 10 to 20 degrees above normal in some spots, especially earlier in the period. This equates to 30s for the North Slope and 50s and 60s farther south near the Southern Coast. Temperatures should trend cooler through much of the period but still above average for this time of the year. Santorelli 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