Alaska Extended Forecast Discussion National Weather Service College Park MD 734 PM EDT Fri Sep 12 2025 Valid 12Z Tue 16 Sep 2025 - 12Z Sat 20 Sep 2025 ***Heavy rain likely for southern and southeast Alaska for early next week as Gulf low approaches*** ...Overview... The beginning of next week is expected to be rather unsettled across the Gulf Coast region from the Kenai Peninsula to southeast Alaska as a storm system moves in from the southwest. This low weakens by midweek as attention then turns to the central and western Aleutians with the next low pressure system developing over that region, and this should track in the general direction of the Alaska Peninsula by next Thursday with additional heavy rain and high mountain snow expected. A stationary frontal boundary across the mainland will separate cold conditions from the Brooks Range northward and mild temperatures across the Interior. ...Guidance Evaluation/Preferences... The guidance has a decent overall handle on the Gulf low pressure system early in the week, and a general deterministic model blend was employed to start with on Tuesday. However, model differences are more noticeable with the next low tracking just south of the Aleutians. The GFS is well to the west of the model consensus, whereas the CMC and UKMET are faster. More weighting was applied to the ECMWF and GEFS/ECENS for this storm system, which resulted in the low track being about 200 miles or so east of yesterday's forecast position through Wednesday night. The ensemble means were increased to about 70% by next Saturday owing to greater than average model spread on the synoptic scale. ...Weather/Hazards Highlights... An organized low pressure system is likely to bring gusty winds and periods of moderate to heavy rainfall to portions of the Kenai Peninsula, South-central mainland, and Southeast Alaska early next week. This should reach peak intensity on Monday night, which is when the frontal system should arrive along the Gulf Coast. The low should weaken going into Tuesday night and Wednesday, with a corresponding abatement in precipitation. Rainy conditions and gusty winds then affect the Aleutians and the Alaska Peninsula by Wednesday into Thursday, followed by the southern mainland coast by Friday where a few inches of rainfall will be possible across the windward terrain. Temperatures will likely be above average across the central and southern mainland, and likely near to below average over the Brooks Range and North Slope region. Hamrick 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