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000
FXAK68 PAFC 251301
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
501 AM AKDT Thu Apr 25 2024

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Today
through Saturday)...
The upper level ridge that stretches from the Yukon through the
Interior of the state can be seen well on satellite creating the
large hole of clear skies this morning. However, this ridge is
being weakened and elongated as a front over Kodiak Island and the
Gulf of Alaska slowly pushes its way northeast and into
Southcentral Alaska. Clouds associated with this front have
mainly overspread the Kenai Peninsula this morning and will
continue to move slowly northeastward through the day. Kodiak
Island is in the rain again but it should be rather light today
with only about a quarter of an inch around Kodiak City and the
eastern side of the Island. After a break this evening and
overnight with the passing of the front, another, wetter front
will move over Kodiak for Friday. This front is the result of a
wave in the north Pacific meeting up with the cold upper level low
that is in the southeastern Bering Sea and will undercut Kodiak
Island tomorrow. This will enhance that North Pacific system and
bring about an inch and a quarter to Kodiak City Friday through
Friday night.

As this upper level low moves south of Kodiak, another upper level
ridge will start to build in over the Interior of the state.
This ridge will not be as strong as the current ridge. but it
should allow at least partial clearing over most of Southcentral
by Saturday while keeping the area generally dry. The one caveat
is that the NAM model is suggesting that there will be an easterly
wave that develops near the Alcan border Saturday night. The GFS
hints at this feature, but is not as well defined as the NAM. This
could bring some rain to the Copper River Basin late Saturday
should it develop. These easterly waves are notoriously
unpredictable so it could just as easily fizzle out as develop

&&


.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3: Today
through Sunday morning)...

The forecast remains on track through the short-term period. A
large vertically stacked continues to take up residency in the
central Bering Sea this morning. Gusty and showery conditions will
persist through the Central Aleutians, Eastern Aleutians, the
Alaska Peninsula (AKPEN), and Pribilof Islands through most today
and into Friday. Showers also continue for Southwest Alaska today
and into Friday as well with multiple shortwaves rotating around
the broad upper low in the Bering.

Another low pressure system lifts northward through the North
Pacific and to the Alaska Peninsula by Friday evening. There is a
little disagreement in where the exact corridor of enhanced
precipitation will set up. However, indications are that it will
be somewhere between the Shumagin Islands and Kodiak Island. This
low does not seem overly strong with mostly small-craft winds
anticipated for the North Pacific marine zones south of the AKPEN.
Meanwhile, the main surface low once in the central Bering will
continue to fill and eventually dissipate south of the Eastern
Aleutians Friday afternoon as moisture lingers across the AKPEN
through Saturday afternoon. This low near the AKPEN eventually
weakens and dissipates through Sunday morning. In the wake of this
low, the southern AKPEN will be left in a northwesterly flow
regime Saturday and into Sunday with gusty northwest winds and
showery rain/snow mix.

A front from a Kamchatka low moves eastward and sweeps the
Western and Central Aleutian Chain Saturday and Sunday bringing
mostly small-craft winds or less, and mostly rain to the area.

&&


.LONG TERM FORECAST (Days 4 through 7: Sun through Wed)...

The low that is currently over the Bering Sea will have meandered
into the Eastern Gulf of Alaska for Sunday and slowly drift south
along the western coast of North America through the early half
of the week. A ridge will likely build behind the low across
Southcentral. Embedded easterly waves could lead to brief showers
in the Copper River Basin each day. A larger, embedded shortwave
is possible for Tuesday along the ridge, but any moisture
associated is still expected to be light and or showery.

Out west, a front is moving through the Bering and across the
Aleutians. For Sunday, the front will be located around the
central to eastern Aleutians and will reach the Pribilofs before
weakening and being replaced by a larger and stronger occluded low
Monday. This low will bring more moisture into the Bering Sea and
Aleutians. Storm force winds look likely for the western
Aleutians Monday morning, weakening to gales by Tuesday. Its front
reaches the Southwest Alaska as early as Tuesday and spreading
the bulk of the moisture to Southwest, the Alaska Peninsula, and
Kodiak Island for Wednesday. Timing of the precipitation will
depend on the position of synoptic feature, the progression, and
orientation of the front. Although the overall synoptic setup is
in better agreement for the extended period, the details could
mean bigger differences in the QPF and wind fields across the
Bering and Southwest Alaska.

rux

$$

.AVIATION...

PANC...VFR conditions will persist. Southeast winds 10 to 15 kts
are expected to develop over the airport late this afternoon into
the evening. Winds are then expected to become light and variable
again overnight.

&&

$$