Alaska Extended Forecast Discussion National Weather Service College Park MD 623 PM EDT Fri Oct 17 2025 Valid 12Z Tue 21 Oct 2025 - 12Z Sat 25 Oct 2025 ...Very wet pattern for the Southeast next week... ...Overview... An elongated upper low (with multiple vortices) will be stationed over the region for much of the period with an axis from eastern Russia, over the Mainland, and the Gulf. The weather across Alaska during the extended range period (Tuesday-Saturday) will be driven by weaker shortwaves rounding the base of the trough from the Aleutians/AK Peninsula into the Gulf. This will support surface low pressure in the Gulf and a generally wet period for the Southeast with heavy rainfall potential early to mid week. ...Guidance Evaluation/Preferences... The guidance is in relatively good agreement with the overall large scale upper pattern, but there remains quite a bit of variability in the details. A surface low will be entering the Gulf around Tuesday and the UKMET is notably faster than the consensus with this and stronger with a shortwave behind. Thus, did not include the UKMET in todays model preferences and blend. The GFS, ECMWF, and CMC formed the basis for the Day 4-6 forecast. Increased ensemble mean contribution to 50 or 60 percent of the blend by days 7 and 8 to account for greater uncertainty with shortwaves into the Gulf and the overall structure of the upper low over the Bering Sea/western Alaska. Another system looks to move into the western Bering Sea towards the end of the period with considerable uncertainty. ...Weather/Hazards Highlights... A cyclone in the Gulf and retreating eastward by Tuesday may continue to produce some Gap winds on the backside across parts of the Southeast coast. Moderate to heavy precipitation may be ongoing across parts of the Southeast. Behind this, another cyclone will cross the Aleutians Monday-Tuesday with accompanying Gusty winds for the Aleutians and some showers. As this system enters into the Gulf late Tuesday into Wednesday, it will allow for another period of moderate to heavy precipitation for the Southeast, with lighter precipitation for the southern Coast and parts of the Mainland. Low pressure will rotate and maintain across the Gulf supporting a multi-day rainfall event at least through Midweek, with several inches of rain possible. Modest precipitation should extend into late week as well, but still some uncertainty on whether it reaches hazards chart criteria or not. Gusty gap winds are possible on the backside of this system in favorable locations. Temperatures across Alaska should trend colder and below normal for most places next week. The North Slope and parts of eastern Alaska may be above normal with influence from some upper ridging. 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