Alaska Extended Forecast Discussion
National Weather Service College Park MD
753 PM EDT Tue Aug 11 2026

Valid 12Z Sat 15 Aug 2026 - 12Z Wed 19 Aug 2026

...Heavy rain over the weekend for the portions of the Aleutians,
Kenai Peninsula and Southwest spreading to the Alaska Peninsula 
and vicinity into next week...

...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...

Through the extended period a blocky pattern will be in place over
the region, consisting of a mean upper low sitting over the 
southern Bering Sea while energies rotate around it from multiple 
directions, and a strong upper ridge anchored across the northeast
Pacific and Southeast Alaska into at least eastern parts of the 
Mainland. A low pressure system is forecast to bring ample 
moisture and 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 into early next week, leading to continued above 
average temperatures. 


...Guidance Evaluation and Preferences... 

Overall the guidance is in decent agreement with the blocking
pattern with varied locations/timing of individual shortwaves 
within the mean trough over the western portion of the region;
which ultimately affect the surface low positions. Elongated 
vorticity carrying a reasonably strong surface low will track 
northeast across the northern Pacific late week and interact with 
the Bering low, with some timing differences. The AIFS continues
to favor on the fast side to bring this low north toward the 
eastern Aleutians by early Saturday, while the 12Z GFS is on the 
slow side, with the ECMWF once again being a decent middle 
ground. The low is made up of energy likely at least partially 
related to current West Pacific tropical systems TD 15W and TS 
Peilou.

Meanwhile, models have trended toward showing Arctic energy 
feeding southward into the preexisting upper low over the weekend 
(rather than keeping them separate features like some guidance 
showed a day ago), also influencing the surface low positions to 
be in the southern Bering into Sunday. Early next week, 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 and ensemble blend 
favoring the ECMWF through the early part of the period, with 
increasing proportions of ensemble means to about half late 
period. 


...Weather/Hazards Highlights...

Mean southerly flow will promote a steady influx of moisture, 
with some tropical influence from TD 15W and TS Peilou, into 
southern Alaska thus keeping the potential for multiple days of 
heavy rainfall. WPC shows a heavy rain area 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. These temperatures are
creeping toward becoming excessive across the south which may lead
to the need for heat advisories with future forecast updates. 
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 are being raised for portions of the 
North Slope to approximately the Atigun Pass for at least the 
weekend.


Campbell/Tate


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