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