Unalaska, Alaska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

861
FXAK68 PAFC 151257
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
457 AM AKDT Thu May 15 2025

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)...

The low centered west of Kodiak Island and its front, which
extends across the north Gulf coast, remain the main weather
features for Southcentral Alaska today. The low and front have
peaked in strength and are both weakening today, but there is
still enough strength to bring some strong winds from Shelikof
Strait and along the north Gulf coast as well as through Turnagain
Arm. As is typical with these set-ups, the precipitation will
mainly be along the Gulf coast and windward sides of the coastal
mountains. The inland and leeward sides of the mountains will
remain dryer, though there is still enough lift along the front to
bring some rain to Anchorage and parts of the western Kenai
Peninsula and the southern Susitna Valley this morning. After that
the cross-barrier flow should cut-off most of the remaining
moisture as the lifting along the front continues to weaken.

After today, the weather across Southcentral looks rather benign
as we head into the weekend. For Friday and Saturday, the upper
level flow is quite weak with residual moisture across the region
keeping skies mostly cloudy. Break in the clouds, especially near
snow-free mountain slopes could produce enough heating for
afternoon and evening showers, but without overly cold air aloft,
the instability will be limited and so should be the extent of
showers.

&&


.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(Days 1 through 3: This morning through Saturday evening)...

This morning, there is a ~988 mb broad low pressure system
spinning just north of King Cove and Sand Point in the Bristol Bay
region. The low and its associated front is causing easterly
30-40 kt gap winds for the Kamishak Gap and westward for areas
near Bristol Bay. The majority of precipitation has remained
offshore, except for the Pribilof Islands, immediate Bristol Bay
area, northern most areas of the AK PEN, for favorable southern
facing slopes of the Aleutian Range due to orographic lift, and
the southwestern most areas of the Alaskan Range. While interior
locations will be mostly downsloped with the easterly flow off the
mountain ranges, light rain will continue across the Bristol Bay
coast and AKPEN through today and push farther inland this evening
as the gusty easterly winds diminish. Farther west, north of
Amchitka, there is some semblance of a weak area of low pressure
that has developed within the rather large trough envelope from
the low in Bristol Bay with light precipitation on its western
flank, which is giving the Western Aleutians some light rain
showers.

Model guidance suggests that the Bristol Bay low begins to
retrograde and weaken late today into Friday, with its front
pivoting from the Western Gulf of Alaska into the Eastern Bering
Sea. Meanwhile, a transient ridge of high pressure will build into
the Western Aleutians and Western Bering for Friday and will
quickly move eastward. This does not appear to be an overly
amplified ridge, but some guidance does show a weak 850 mb
inversion building aloft as the ridge moves across the region. If
the guidance that shows the inversion solution is closer to being
correct, then it would prevent some mixing down gradient from the
surface to aloft, which could lead to some degree of foggy and
misty conditions for a short time on Friday. This ridge will
weaken as it moves east over the Central Aleutians for Saturday. A
Kamchatka low sends its front to the Western Aleutians and
Western Bering Saturday, which will bring a round of gusty
southerly winds and rain to the area.

-AM/DN

&&


.LONG TERM FORECAST (Days 4 through 7: Sunday through Wednesday)...

An extensive upper level low covers the region during the
forecast period. The main portion stretches from the Russian Far
East across the Aleutians and Alaska Peninsula into the Gulf of
Alaska through midweek, briefly interrupted by weak ridges passing
through the pattern on Sunday and Tuesday. Upper level jet
support remains to the South over the North Pacific. Upper low
centers slip through the pattern along and over the Aleutians into
the Gulf of Alaska. Model guidance is in decent agreement through
most of the forecast, but surface feature development and
movement hold on to the most uncertainty.

Scattered showers will be the order of the day across the
Southern Mainland through Wednesday. A well developed low
approaches the AKPEN before brushing past Kodiak Island into the
Gulf of Alaska through Tuesday. A strong low and front spreads
rain over the Western Aleutians and Bering Sunday pushing across
to the Central Aleutians before curving back into the North
Pacific for Wednesday.

- Kutz


&&

.AVIATION...

PANC...VFR conditions and light northerly winds will persist
through this morning. A Turnagain Arm wind will redevelop this
afternoon, bringing southeasterly winds up to 20 kts to the
terminal through the evening hours. Light and variable winds will
return to PANC tonight through Friday morning.

&&


$$