Alaska Extended Forecast Discussion
National Weather Service College Park MD
734 PM EDT Wed Oct 8 2025
Valid 12Z Sun 12 Oct 2025 - 12Z Thu 16 Oct 2025
...Series of potent storms offer Aleutians to western and
southern Alaska high wind/wave and heavy rain threats...
...Guidance Evaluation and Preferences...
A mean trough will be present through the extended period over the
Bering Sea. Multiple deep, closed lows will lift northward while
while several impulses of energy ejects from the flow into the
Gulf of Alaska/Mainland. The latest guidance continues to have
above average clustering with the leading low and now the
secondary low Sunday into Tuesday before spread increases by
midweek, particularly across the Gulf of Alaska. The energy and
moisture associated with the current Pacific Typhoon Halong will
be traveling in the westerlies to Alaska this weekend into early
next week which accounts for some of the increased uncertainty.
Maintained continuity by starting with equal weighting of the
CMC/EC/GFS, including the EC/GEFS means over the weekend and then
bumping up to a 60/40 deterministic to means ratio by the end of
the extended period.
...Weather/Hazards Highlights...
A stormy weather pattern will remain across Locally enhanced
winds and precipitation Upper trough energy split over the
northern Gulf of Alaska may also act to focus modest mid-late week
low development with some precipitation/unsettled weather for
southern/southeast Alaska, followed by weekend frontal passage and
some moderate gap flows. A closed upper low/trough development
will support a main deep mean surface storm/low position over the
Aleutians and Bering Sea late week through early next week that
will offer a prolonged opportunity for periods of high winds/waves
and wrapping rainfall. There continues to be a growing signal
within the guidance for a deep and potent storm to lift in advance
of this position over the weekend into early next week to focus a
potentially significant threat for high winds/waves, wrapping
rainfall and potential for coastal flooding into Southwest/Western
Alaska along with enhanced snow potential more over colder
northwestern Alaska. This strong extra tropical low will have
favorable upper support and a deep moisture connection to Typhoon
Halong. Approach and downstream undercutting energy and
system/frontal progression across the Alaska Peninsula into the
Gulf of Alaska should act to enhance lead inflow to fuel growing
precipitation to spread across Kodiak Island and SouthCentral to
Southeast Alaska Sunday into early next week with downstream
translation. Additional deep low approach on the heels of this
system is also then possible.
Campbell
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