Alaska Extended Forecast Discussion
National Weather Service College Park MD
703 PM EDT Wed Aug 12 2026

Valid 12Z Sun 16 Aug 2026 - 12Z Thu 20 Aug 2026

...Heavy rain potential for the portions of the Aleutians, Kenai 
Peninsula and Southwest spreading to the Alaska Peninsula and 
vicinity...

...Excessive heat for portions of the North Slope this weekend
along with persistent above normal temperatures for Southeast 
Alaska through much of the Mainland...


...Overview...

A blocky pattern will persistent across the region with upper
ridging over the eastern Alaska/Yukon and a mean trough/upper low
with multiple shortwaves moving through over the southern Bering
Sea/northeast Pacific. A low pressure system will usher in ample 
moisture and spreading potentially heavy rain across portions of 
the Aleutians, Kodiak Island, Southwest, Alaska Peninsula eastward
to Southcentral areas. The upper ridge to the east will remain 
entrenched leading to continued above average temperatures. 


...Guidance Evaluation and Preferences... 

Guidance is in good agreement with the blocky pattern and
continues to have varied locations/timing of individual 
shortwaves within the mean trough over the western portion of the 
region; which ultimately affect the surface low positions. The CMC
and the UKMET persist in taking a strong surface low further
north toward western Mainland whereas the EC and the GFS maintain
a position near the Aleutians/Southwest Mainland. Some of this
uncertainty may be contributed to energy partially related to West
Pacific tropical systems.

Models still depict Arctic energy feeding southward into the 
preexisting upper low over the weekend also influencing the 
surface low positions to be in the southern Bering into Sunday. 
There is good model agreement that the pattern should stay fairly
stationary with the upper/surface low meandering over the 
southeastern Bering Sea and the ridge in the east.

The WPC forecast was based on a multi-model blend with a heavily
lean to the EC initially and then transitioned to a GFS/EC
compromise with EC AIFS/EC and GEFS means for the mid to late
period.


...Weather/Hazards Highlights...

A steady influx of moisture, with some tropical influence from
remnants of 15W and Peilou, into southern Alaska thus keeping the
potential for multiple days of heavy rainfall. WPC shows a heavy 
rain areas on the Day 3-7 Hazards chart. A reasonably strong 
northern Pacific low likely crossing/reforming in the southern 
Bering Sea should lead to another round of heavy rain and 
potentially leading to gap winds in the favored locations along 
the coast. High winds are also a possibility, but the placement 
and direction of strong winds will vary dependent on the low 
track. The eastern Interior to Southeast Alaska should mostly be 
dry underneath upper ridging through late week, though chances for
showers may increase by next weekend depending on the eventual 
evolution with that low.

Temperatures will be broadly warmer than average in most areas 
through the period, given southerly flow and ridging aloft. Highs 
in the 70s and 80s are forecast for Interior areas for multiple 
days, which could exacerbate fire conditions. 60s and 70s will be 
common with a few locations reaching the low 80s in Southeast 
Alaska, and this anomalous warmth could affect the Mendenhall 
Glacier- related flooding potential. Southcentral can expect 
highs into the 70s, with 60s and upper 50s for southern coastal 
areas. The coastal towns of the North Slope could see 50s for 
highs, with 60s to around 70 in the Arctic Plains. Heat advisories
remain in effect for portions of the North Slope to approximately
the Atigun Pass for at least the weekend.


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