Gale Warning 611, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
452 AM AKDT Fri Sep 13 2024

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

Two upper level lows/shortwaves will continue to breakdown and
weaken as they move east over the next 24 hours. Most of the
precipitation, that was very widespread yesterday, now resides
over the eastern Sound, high terrain of the Chugach and Talkeetna
Mountains, and portions of the Copper Valley. By this afternoon
ridging will take hold of most of the region, bringing dry
conditions and some sunshine from Kodiak north through the
southern Mat-Su. With this, valley locations that do remain clear
and free of stratus and/or fog overnight may see temperatures in
the upper 30s come Saturday morning.

This ridging and dry weather will be short, as a moderately strong
jet begins to point itself right at Southcentral for the weekend.
Rain will reach Kodiak Island Saturday morning and quickly spread
northeast to most areas for Saturday afternoon and through at
least Sunday morning. At the surface, winds will pick up through
the typical gaps and passes of the coastal mountain ranges. These
will be mitigated by a triple point low developing in the Gulf
near the Barren Islands Sunday morning, however the primary low
associated with this broad trough is much deeper and near the
Bering Strait, which will result in gap winds transitioning over
to southerly, up-inlet flow. For late Sunday into Monday, broad
southwesterly flow will keep the region cool and cloudy, with
upslope precipitation.

&&

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

A low over Kamchatka drops south into the northern Bering Sea and
tracks east towards the West Coast. The associated front digs
south into the western Bering today. There is a decent pull of
moisture out of the Pacific that will be carried over the Aleutian
and Pribilof Islands as well as Southwest Alaska as the front
progresses eastward through this weekend. Widespread rain and
gale force winds are expected along the front through the weekend.

As the system will continue to slowly deepen on its journey to
the vicinity of Saint Lawrence Island and perhaps remain nearly
stationary there Sunday through Sunday night. With this track, a
sustained fetch of southerly to southwesterly winds is favored
coming off the eastern Bering and into the coast of Southwest and
especially the Kuskokwim Delta Coast. Thus, a Coastal Flood Watch
has been issued for the along the Kuskokwim Delta Coast from
Saturday morning through late Sunday night from the mouth of the
Kuskokwim River to Newtok. In addition, due to persistent
southerly to southwest winds up Kuskokwim Bay, a River Flood Watch
has been issued along the Kuskokwim River from Bethel to the
mouth of the river Saturday afternoon through Sunday afternoon.
The greatest push of southerly winds looks to be Saturday morning
into the early afternoon before winds turn more southwesterly
during that time, but persist into Sunday night.

&&

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

Models are in loose agreement to start off the long term period
on Monday with an upper low south of Kamchatka lifting across the
Western Aleutians by Monday afternoon. Previously, operational
models had taken this low on a more southerly track with potential
for stronger winds across the Aleutian Chain through Tuesday.
More recently, however, the operational models have trended
substantially further north, with agreement between the models
becoming much poorer. This has resulted in putting more confidence
in the ensemble guidance, which has been more consistent and in
better agreement keeping the southerly track of the upcoming low.
What this means is a continued active pattern for the Bering and
Southwest Alaska with above normal precipitation chances expected
and potential for elevated winds as a low and its attendant front
span the entire west domain.

Conditions will be somewhat quieter to start off the long term
period for Southcentral. A trough over interior Alaska should be
in the process of departing to the northeast with brief high
pressure setting into Southcentral on Monday. However, ensemble
guidance brings the previously mentioned Bering low and its
attendant front into Southcentral by late Tuesday with increasing
precipitation chances. These precipitation chances look to linger
through the second half of next week with seasonably normal
temperatures for the region.

BL

&&

.AVIATION...

PANC...While it is possible for some low stratus and fog to move
in from the north this morning, conditions should remain VFR
through the period with light winds.

&&