975
FXAK68 PAFC 181245
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
445 AM AKDT Fri Apr 18 2025

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

The center of a broad and disorganized upper level low is
currently over Southcentral, bringing widespread shower activity
to the region today. The airmass in place is quite unstable,
showing near dry adiabatic lapse rates in the lower levels in the
0Z sounding, helping the marginal amount of upper level support
generate precipitation. Towards the afternoon the showers will be
more focused around westerly facing terrain as the sun helps to
heat things up a bit. Additionally, the widespread breezy
conditions over the past few days will come to an end as a weak
low develops south of the Sound.

For Saturday expect generally drier weather as a shortwave ridge
attempts to build in to the west, though a perturbation moving
from the northern Susitna into the Copper Valley will keep those
areas a little bit on the cloudy side with a chance of light
showers developing. Otherwise, winds should be calm and
temperatures pleasant for the region`s first nice day in quite
some time. Sadly the sunshine is likely to be short-lived as an
occluded front moves into Kodiak Sunday morning and then into the
Kenai Peninsula late Sunday. While inland areas may be somewhat
downsloped, the southeasterly winds aloft aren`t overly
impressive, so rain may spill over into Anchorage and the Mat-Su
Valleys on Monday. Snow levels for this system are expected to be
between 800ft and 1500 ft, with the higher values towards Homer
and Seward.

&&


.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days
1 through 3: Today through Monday)...

Currently, as of 12 AM, the low that has brought snow and rain to
Southwest Alaska continues to dissipate as it moves east. Showery
precipitation mostly in the form of snow continues to fall in the
Bristol Bay and Kuskokwim Delta regions as the low moves out.
This will end by Friday afternoon as a ridge pushes in from the
west. Cold air advection will end in the west coast Friday
afternoon when winds turn southerly. Speaking of the ridge, it is
currently over the Aleutians and Alaska Peninsula regions, which
is allowing for calmer and drier weather. This drier weather,
however, will be short lived as a weak front moves in from the
west, briefly increasing precipitation chances in the Eastern
Aleutians and Alaska Peninsula by Friday morning. Wind speeds will
remain on the lighter side. Isolated showers will linger in these
regions through Saturday.

By Friday afternoon into Saturday, the next weather maker will
make its appearance. A weak low will push into the western
Aleutians, driving precipitation chances up and slightly
increasing wind speeds. This precipitation will be in the form of
rain due to southerly flow bringing in a warmer air mass. Saturday
afternoon into Sunday has the low tracking eastward and driving a
front into the eastern Aleutians and Southwest mainland,
increasing precipitation chances and wind speeds in those regions.
Again, most precipitation will be in the form of rain, but the
Kuskokwim Delta coast including Nunivak Island could see snowfall
early Sunday that transitions to rain by the afternoon due to warm
air advection from southerly flow.

The story doesn`t end there as another low arrives in the western
Aleutians Sunday afternoon. There is uncertainty with the track
and strength of the low, but it may be a bit stronger than the
previous one. This low however, will still be fairly weak. Winds
will be small craft near Adak by Monday before the low moves
eastward and weakens. Showery precipitation in the form of rain
will also occur with this low. By Monday afternoon, another bout
of rain will affect the mainland as the low pushes inland. As for
wind speeds, they will only have a slight increase as the low will
be quite weak by the time it arrives in the mainland.

-JAR

&&
.LONG TERM FORECAST (Days 4 through 7/Monday through Thursday)...

A broad upper level low dominates the Alaska Weather map moving
from the Bering to cover Interior Alaska by midweek and flexing
through the end of the forecast period. A few upper level low
centers and several shortwaves moving through the flow keeps the
overall pattern fairly unsettled, but most of the active weather
will occur across the Southern portions of the state. A well
clustered mix of GFS / ECMWF / UKMET and Canadian models support
large scale feature movements and strengths, with the greatest
uncertainty bundled in the smaller surface details.

On the surface, a large area low center in the West-Central
Bering extends a front across Southwest Alaska and the Alaska
Peninsula into the Gulf of Alaska on Monday. Areas of snow or rain
mixed with snow move over the Northern Bering and Southwest
Alaska, with all rain spreading over Kodiak Island, Southcentral
Alaska Coast and the Gulf of Alaska on Monday. This low weakens as
it moves into Bristol Bay and dissipates early Tuesday. A low
forming South of the Aleutians picks up the slack Tuesday,
bringing another round of rain across the Gulf of Alaska and
Southcentral Alaska through Thursday. Developing in the West, a
strong North Pacific low pushes a front over the Western Aleutians
and Bering Tuesday. Locally heavy rain and gusty winds spread
Eastward through Thursday.

- Kutz

&&

.AVIATION...

PANC...Southeasterly winds will diminish through today as a low
pressure system develops south of the Sound. Showers will be in
and out of the terminal this morning, which may drop cigs to MVFR.
Rain should be more focused over the Chugach this afternoon as
westerly winds develop aloft.

&&


$$