Alaska Extended Forecast Discussion
National Weather Service College Park MD
655 PM EDT Fri Mar 20 2026

Valid 12Z Tue 24 Mar 2026 - 12Z Sat 28 Mar 2026


...Overview...

The upper pattern will be quite amplified at the start of the
period Tuesday, with a ridge axis atop the Bering Sea and
troughing across the eastern half of Alaska. Into midweek, an
upper low is forecast to develop over the Northeast Pacific, while
a shortwave over eastern Siberia pushes the north side of the
ridge into the North Slope. This pattern should lead to mainly dry
conditions, aside from light precipitation into Southeast Alaska
and eventually some precipitation into the Aleutians/possibly the
western Mainland by late week into next weekend. Colder than
average temperatures should prevail other than the North Slope
given the ridge aloft.


...Guidance Evaluation and Preferences...

Model guidance is reasonably agreeable with the large scale 
pattern described above, especially early in the extended period. 
However, one challenge for Tuesday-Wednesday is with a surface low
position tracking northward somewhere near Haida Gwaii. The 00Z 
ECMWF was farther northwest and stronger with this low, but the 
12Z run did come into better consensus with other guidance. Models
agree that the low should weaken as it moves north toward 
Southeast Alaska. Another low or two over the Northeast Pacific 
show some model variations mid to late week, but well within 
typical spread.

Farther north, models have a good consensus with the northern end
of the upper ridge getting pushed eastward into the North Slope 
by shortwave energy coming across eastern Siberia. There is more 
uncertainty by Thursday into Friday with possible additional 
arctic energy. GFS runs energy diving south and disrupting the 
upper high, but the 12Z EC/CMC held onto the high. The AI models 
have some semblance of troughing, so those and the ensemble means 
are probably the best middle ground. By late next week, will 
continue to monitor a upper/surface low moving east across the 
Aleutians and Bering Sea. Models currently agree in the existence 
of this feature, but show spread in strength and timing.

The WPC forecast used a blend of deterministic models and the 
AIFS early in the period, with increasing proportions of the 
ensemble means to half by Days 7-8, amid increasing spread. 


...Weather/Hazards Highlights...

Tuesday-Wednesday's aforementioned low pressure system in the 
northeastern Pacific should be south of the state, but could 
nevertheless provide light to moderate precipitation in Southeast 
Alaska. The low also seems too far south to cause anything 
widespread in terms of high winds. But the broader pattern of 
rounds of low pressure in the northeast Pacific could cause some 
moderate gap winds (generally less than 40 knots) in favored areas
of the Alaska Peninsula and Southeast Alaska at times. Additional
rounds of precipitation could continue in Southeast through much 
of the week, and light precipitation may make it into portions of 
Kodiak Island and Southcentral too. In the Northwest and Seward 
Peninsula, precipitation and high wind chances may be nonzero by 
Wednesday night into Thursday as a shortwave moves through. The 
Alaska Mainland should be mostly dry given the continental flow 
pattern. But an approaching low pressure/frontal system is 
forecast to move east through the Bering Sea and lead to 
precipitation chances in the Aleutians and gradually spreading 
toward the Alaska Peninsula and western Mainland by next Friday-
Saturday.

The flow pattern should also produce colder than average 
temperatures, especially for the southern half of the state, next 
week. Expect highs near the freezing mark in Southcentral, 20s and
teens across much of the Interior, and 30s in Southeast. 
Temperatures should gradually moderate into late week. For the 
Seward Peninsula into the North Slope, temperatures will generally
be above normal due to the upper ridge influence, with highs 
becoming milder into the teens perhaps even for the Arctic Coast 
communities.


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