Gale Warning 154, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
447 AM AKST Sun Feb 9 2025

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

The weather forecast remains on track with a ridge across
mainland Southcentral keeping those areas dry and quiet through
the early half of this week. Meanwhile, rain will continue
primarily for Kodiak Island as multiple troughs lift north.
Chances for precipitation spread into portions of the south and
eastern Kenai Peninsula through at least Tuesday. Confidence is
high for the overall outlook, with slightly less confidence on the
northward and eastward spread of precipitation away from the
western Gulf.

Light rain showers and east to southeasterly winds linger for
Kodiak through the rest of this morning. Higher elevations across
the Island will continue to have snow as snow levels are not
expected to vary too much from around 1500 to 2500 feet over the
next couple days. A North Pacific low is lifting north toward the
Alaska Peninsula and Kodiak Island. Precipitation intensity will
increase as the trough arrives this afternoon and will last until
at least Monday morning. Winds across Kodiak Island are expected
to increase to gale force with the passage of this low this
afternoon. Easterly winds around the Barren Islands are expected
to peak around 50 to 60 mph Monday morning and again early Tuesday
morning when yet another trough lifts north Monday night into
Tuesday. Additional precipitation with the following trough could
be heavy at times. Rainfall totals over the next 24 hours are
expected to be around an inch for Kodiak. The next trough late
Monday through Tuesday could bring an additional two more inches.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days
1 through 3: Saturday Night through Tuesday Morning)...

Gusty winds continue across the Kuskokwim Delta and Bristol Bay
coasts as well as the AKPEN in response to a tightened pressure
gradient with a high pressure ridge remaining over mainland
Alaska. Any remaining showers over the Kuskokwim Delta are
expected to push northward through this morning, with another
round of showers expected Monday morning as an upper-level
shortwave moves through ahead of the next system.

Farther out west, a North Pacific low-pressure system is
currently rapidly intensifying south of the Aleutians, driven by a
large upper-level low off the coast of the Kamchatka Peninsula.
This upper-level low provides the broader steering flow for the
surface low, which is expected to gradually rotate northward,
drawing the occluded front into the Aleutians through this
morning. The northward movement of the low is enhanced by
divergence in the left exit region of a very strong 200 kt zonal
jet streak, which will also contribute to rapid deepening, with
central pressures expected to bottom out as low as 940 mb as it
crosses the western Aleutians later today. Gale-force winds will
spread across the entire Bering and Aleutian chain, extending to
the Southwest Coastline through Monday.

As the system intensifies, a secondary 120 kt jet streak is still
forecast to form downstream to the east of the low in response to
tightening thermal gradient downstream of the occlusion, in turn
enhancing the low-level jet (LLJ) across the eastern Bering Sea
and into Bristol Bay by Monday morning. Despite some variation
among models, strong coastal and offshore winds remain likely.
Winds may approach storm-force, with wind gusts of 50 to 60 mph
expected, particularly from the eastern Aleutians to over Bristol
Bay and the Alaska Peninsula, and potentially the Kuskokwim Delta
coast as well.

The low will also interact with significant moisture advection,
with high integrated vapor transport (IVT) values supporting
widespread precipitation along the occluded front. However, the
front’s relatively fast progression will limit precipitation
amounts across the eastern Aleutians to around or just over an
inch, particularly from Unalaska to Cold Bay, with higher amounts
over the southern AKPEN. The front begins to fall apart before
reaching the Southwest Alaska coast, weakening under the influence
of the ridge, with only the far western Kuskokwim Delta, Nunivak
Island, and the Bristol Bay coastal seeing any precipitation,
upwards of a half an inch. While coastal flooding remains a
concern, extensive shorefast ice and near-total ice coverage in
Kuskokwim Bay will likely mitigate impacts that could otherwise
contribute to flooding.

By Tuesday morning, both winds and precipitation will diminish as
the parent low (previously centered over the western Aleutians)
continues to progress towards Kamchatka, leaving the blocking
ridge in place, though slightly displaced east; quieter weather
then returns to the Aleutians Chain, Bering Sea and Southwest
Alaska.

Eovino

&&

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

A change in the weather pattern is expected for Southcentral
throughout the long term period while active weather will continue
out west for the Alaska Peninsula, Aleutians, and Bering Sea.
Despite the shift in weather pattern, deterministic model and
ensemble guidance are well clustered through Friday, with a shift
to an ensemble mean blend for the end of the period as model
spread increases. The main feature for the beginning of the period
will be the bisection of the upper ridge responsible for recent
calm conditions across Southcentral Alaska by an east- west
oriented trough originating in Western Canada. The westward
expansion of this trough will allow for the intrusion of a colder
airmass and a large upper level low centered over Interior Alaska
to encompass much of the mainland through Friday. Meanwhile, a
strong vertically stacked low in the Western Bering weakens as it
moves into Siberia, allowing for showery weather to persist for
the Western Aleutians through Wednesday. A weak North Pacific low
has potential to bring locally heavy rain to the AKPen and Kodiak
Island through Wednesday and light showers to the Gulf coast
through Friday.

Persistent shortwave energy will continue to propagate out of the
North Pacific into the Western Gulf and across the Aleutians and
Alaska Peninsula through the period. By Friday, the next strong
North Pacific front will reach the Eastern Aleutians, AKPen, and
Kodiak Island bringing another round of potentially heavy rainfall
through the end of the period before making its way into Bristol
Bay and towards the Gulf coast by the weekend. Expect strong
southeasterly flow to begin to erode the colder airmass across
Southcentral Alaska and bring gusty conditions for the AKPen,
Kodiak Island, and through the Kamishak Gap. An additional low in
the far western Bering enters the picture on Friday, but quickly
stalls and weakens with its front dissipating as it reaches the
Western Aleutians by Saturday.

&&

.AVIATION...

PANC...VFR conditions expected to continue through much of the
period; however, with high pressure remaining overhead, fog and
low clouds may redevelop over Cook Inlet by early Sunday morning.
Otherwise, calm winds and largely clear skies to continue tonight
into Monday.

&&