Alaska Extended Forecast Discussion National Weather Service College Park MD 719 PM EST Sun Nov 2 2025 Valid 12Z Thu 06 Nov 2025 - 12Z Mon 10 Nov 2025 ...Strong low pressure system could affect the Aleutians Friday into next weekend... ...Overview... A mean upper trough axis is forecast to be atop the western Mainland through much of the extended period, as an amplified ridge holds over northwestern Canada into the Arctic Ocean just to the trough's east, blocking its movement. A couple of rounds of energy aloft on the southern side of the trough and surface low pressure systems will move through the northeastern Pacific and bring some light to moderate precipitation to Southcentral and Southeast Alaska, along with moderate gap winds on the backside. Upstream, the next upper/surface low looks to reach the Aleutians vicinity Friday and into next weekend, with typical model spread in its placement. The trough pattern should gradually cool temperatures across much of the Mainland and the Alaska Peninsula compared to the short range, with the most below normal anomalies across the Y-K Delta. ...Guidance Evaluation/Preferences... Model guidance is reasonably agreeable regarding the synoptic scale pattern described above, with most of the differences in the early part of the period in the details. However, details like placement of individual surface low(s) in the Gulf/northeast Pacific in particular could cause sensible weather concerns. Most model guidance has low pressure in the Gulf of Alaska leading to some northwesterly gap winds on both sides of Kodiak Island, but the 12Z ECMWF took a low farther north into Southcentral by early Friday. This is possible but did seem to be against consensus that shows an offshore low. Overall, the early part of the forecast used a multi-model blend of the operational guidance, with the blend smoothing out some of the individual model differences. Greater model differences arise upstream as vort maxes moving east across the northern Pacific and from Kamchatka initially both carry surface lows. Most guidance shows one low becoming dominant by Friday, reaching the 960s or 950s mb, but the 12Z GFS maintains both lows as strong into early Saturday. There is typical track uncertainty with the surface low as it could cross the Aleutians perhaps multiple times in the mean track eastward. The 12Z ECMWF is once again slow to bring the low east compared to the other models that are faster. As the forecast period progressed, gradually used more ensemble means in the model blend to temper these individual model differences, with the blend composed of 60 percent ensemble means by Days 7-8. ...Weather/Hazards Highlights... As multiple surface lows combine in the Gulf/northeast Pacific by Thursday, moist inflow will maintain precipitation chances across Southcentral and Southeast Alaska through much of the week into next weekend. Totals should stay pretty modest though. Farther inland, light snow showers are possible across the Mainland. On the backside of the northeast Pacific low pressure pattern, gap winds are possible and could focus west and east of Kodiak Island. These should generally be in the 30-45kt range, and thus staying below thresholds for a High Winds hazard. Light precipitation is possible across the Aleutians to Alaska Peninsula around Thursday, but the stronger low pressure system affecting the Aleutians should come in with relatively heavier precipitation around Friday and reaching the Alaska Peninsula later Saturday, depending on the low track and timing. High winds are also possible, with southerly flow ahead of the low system Friday, and then the core of the low pressure system may track over the western Aleutians Friday night and east across the Aleutians on Saturday. This allows for a High Winds area for Friday-Saturday in the Day 3-7 Hazards. The low generally looks to weaken as it moves east into early next wee Model guidance is reasonably agreeable regarding the synoptic scale pattern described above, with most of the differences in the early part of the period in the details. However, details like placement of individual surface lows in the Gulf/northeast Pacific in particular as they interact and possibly merge could cause sensible weather concerns. Most model guidance has low pressure in the Gulf of Alaska leading to some northwesterly gap winds on either side of Kodiak Island, while GFS runs kept most low pressure farther south, which limits winds. The newer 18Z GFS has hints of a surface low farther north now though. Overall, the early part of the forecast used a blend of the 12Z ECMWF, 12Z and 06Z GFS, and 12Z CMC. Greater model differences arise upstream as vort maxes moving east across the northern Pacific and from Kamchatka initially both carry surface lows, with the southern one seemingly becoming dominant. The model consensus for the low appears to be near the Aleutians late week into next weekend, but if and when the low crosses the Aleutians is in question, given model and ensemble member spread. The 12Z GFS seemed to be a fast and south outlier by next Saturday (though does have support from the albeit older 00Z GFS Graphcast), while the 06Z GFS was a bit slower and farther north like the ECMWF/CMC. Then the 12Z ECMWF retrogrades the low by next Sunday though, which may be questionable but depends on upstream energy. The 12Z CMC may have been the best middle ground with a steady track east. As the forecast period progressed, gradually used more ensemble means in the model blend to temper these individual model differences, with the blend composed of 60 percent ensemble means by the end of the period.k, but will continue to monitor potential sensible weather impacts as it tracks toward the Mainland. Alaska will generally see a cooling trend during the medium range period. By Thursday, the Alaska Peninsula and Y-K Delta will see below average temperatures for both highs and lows with the core of the trough aloft, which should last there and expand farther north and east into late week. The North Slope and some eastern lower elevation areas like the Yukon Flats may be the main places that stay above average by next weekend. Southeast Alaska could be slightly above normal on average as well. Tate 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