805
FXAK68 PAFC 061300
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
500 AM AKDT Sun Apr 6 2025

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Today
through Tuesday Night)...

A broad area of low pressure with multiple embedded centers of
circulation remains to the south of Kodiak Island this morning.
Southcentral Alaska will continue to be impacted by several rounds
of rain (and high elevation snow) focusing along a series of trough
axes rotating across the Gulf of Alaska into the north Gulf coast.
Locations from Kodiak Island northeast through the eastern Kenai
Peninsula and Prince William Sound will receive multiple rounds of
precipitation through early next week, while inland locations
continue to experience dry downsloping conditions at least through
today, with higher confidence for precipitation heading into next
week.

Another shortwave trough currently lifting into the Kenai Peninsula
will produce similar weather to that observed over the past couple
days, with generally light showers possible for inland areas. One
main difference will be the potential for a band of precipitation to
set up and bring up to a tenth of an inch of rain to the
southwestern Kenai Peninsula and southern Kachemak Bay through the
end of the day. Then, one of the more consolidated low centers
tracks solidly into the Gulf of Alaska. Uncertainty with the track
of the low leads to more significant differences in the potential
sensible weather across Southcentral beyond this point.

The forecast envelope continues to shift broadly northward and is
beginning to focus more toward a northern solution. This means there
is now a better than even chance that the low tracks closer to the
eastern Kenai Peninsula or even into Prince William Sound Sunday
night, with implications for precipitation spreading over inland
areas. Based on present model solutions for the most favored areas
of precipitation, chances  have been raised to likely Sunday night
into Monday for Anchorage and the Matanuska Valley. However,
portions of the Susitna Valley and western Kenai Peninsula may also
see precipitation, depending on the exact track and evolution of the
low.

Also on Sunday night, an upper-level trough digging from the Arctic
brings much cooler air into the Cook Inlet region, with temperatures
forecast to drop below freezing and as low as the mid 20s for many
locations. This will make the dominant precipitation type, if not
the entirety of the event, snow, especially as temperatures rebound
only into the mid 30s for Monday. A wide range of snowfall amounts
are possible with the current level of uncertainty, so while one to
two inches of snow have been added into the forecast, the unstable
air mass with much cooler temperatures moving in aloft will be ripe
to produce bands of snow with high snow ratios, and localized areas
that are difficult to resolve at present could see more. However,
there is still significant potential for a more southern low track
that would leave most of inland Southcentral dry (though cooler
temperatures are expected regardless).

Heading into Tuesday, temperatures rebound somewhat, but lingering
low pressure in the Gulf of Alaska, depending on exact location, may
lead to additional rounds of inland rain and snow. Along the coast,
temperatures generally remain warm enough for rain at sea level,
though some locations could see periods of snow heading into next
week, and areas at higher elevation, particularly Thompson Pass, can
expect upslope precipitation to bring several inches of snow
accumulation each day.

&&


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

A surface and upper level ridge is situated across much of the
Bering Sea while a weak area of low pressure this morning is
bringing nuisance rain and snow showers to the Western and Central
Aleutians. Meanwhile, across Southwest AK, a vigorous 500 mb
shortwave trough is draped across the region, and bringing with it
cold air advection reinforced by a northerly flow, cooling
temperatures and increasing Alaska Peninsula gap winds.

Much of the operational models depict a weak wave of low pressure
emanating from the Bering Strait late Monday morning moving
southeastward toward Nunivak Island and the Kuskokwim Delta. This
feature will bring a quick round of precipitation for these areas,
with 1 to 3 inches of snow possible. The low quickly dives
farther southeastward by early Tuesday, and brings low end impacts
to the Eastern Aleutians and the Alaska Peninsula in the form of
light snow and enhanced wind. With moisture being the limiting
factor, accumulations should be light at sea level, but higher
elevations could wind up with 6+ inches of snowfall. The
combination of snowfall and gusty winds will likely reduce
visibilities Tuesday morning before the wave moves into the North
Pacific later in the day. High pressure quickly builds back in
across the western Bering while an upper level low digs south from
northwest Alaska on Wednesday.


&&


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

The second half of the week will be dominated by a cold upper level
trough that will stretch from north-to-south over the state. This
will bring in generally colder temperatures than have been seen
recently in Southcentral and continued cooler weather for Southwest
Alaska through the Eastern Aleutians.

While there is high confidence in the presence of general location
of the upper level trough, the bigger questions arise when trying
to discern the finer details that will determine where and snow
and/or rain will fall. Part of this uncertainty is due to the GFS
model being a significant outlier from most other models in that
it brings a closed upper level low far south of the Gulf of
Alaska where it looks more likely that when the initial upper low
center reaches the Gulf, a reinforcing wave will swing southward
along the western Alaska coast and keep the main trough in place
over the state instead of allowing it to proceed southward.

What this means from what the most likely sensible weather is that
there will probably be persistent snow showers from the eastern
Aleutians and Alaska Peninsula and possibly reaching the
Kuskokwim Delta and Bristol Bay. Inland parts of Southcentral,
while getting above freezing during the day, will probably mainly
see snow as the precipitation type, but precipitation during the
afternoon will favor rain unless it is coming down heavily.
Farther south, along the north Gulf coast, is where there will be
the most precipitation- type questions as it will be warmer and
likely mostly rain at sea level with snow during overnight hours.
However, if the colder air builds in a little stronger, even the
Gulf coast could see some snow during the daytime hours. While it
is too early to be able to call out where there could be heavier
areas of snow late this week, there could be some areas that do
see some surprisingly heavier snow amounts in this pattern. It is
still early April and winter is not quite finished yet.

&&

.AVIATION...

PANC...VFR conditions with light northerly winds are to be
expected through most of the period. Light rain with a passing
trough this afternoon may reduce visibility to MVFR at times,
accompanied by a shift to southeasterly Turnagain Arm winds
gusting as high as 20-25 kts. Light northerly winds return tonight
with vicinity showers and VFR conditions for the rest of the
forecast period.

-AM

&&
$$