Gale Warning 726, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
450 PM AKST Fri Nov 24 2023

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

There is a closed upper low south of Dutch Harbor and hovering
over the Central Aleutians that will continue to kick shortwave
energy into Southcentral Alaska. Expect more moisture advection
and more southerly flow. Ted Stevens International Airport reached
42F this afternoon, and even Gulkana reached 35F today. The
models are in good agreement with the synoptic pattern but there
are model differences in the short term forecast period regarding
the timing and progression of this series of shortwaves. By Monday
that upper level low will be north of the Alaska Range, and all
the while kicking more shortwaves into Southcentral. On satellite
imagery there are fetches of tropical moisture in the central and
west Pacific Basin. The models suggest this tropical moisture will
steer towards Alaska with the longwave trough in place.

&&

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

An upper-level low continues to weaken across the eastern
Aleutians. The aforementioned low will continue to usher in warmer
air with gusty southerly winds continuing through tonight.
Meanwhile, another upper-level low will track into the far western
northern Bering by tonight with it's southerly gale-force front
draped across the western Bering. Confidence is high that this
will be a gale-force front, with localized areas of embedded storm
force winds. Behind the aforementioned front, strong cold air
advection will bring gusty westerly winds across the Bering
following the front through this weekend and into next week. The
minor challenge with this front continues o be identifying where a
triple point low develops along the occluding front. This
developing low(s) will lead to increased winds in their immediate
vicinity, giving lower confidence in where these stronger winds
could develop. The front is expected to reach the Pribilof Islands
by Saturday night and then the Southwest coast by Sunday. With
this front, heavy to moderate precipitation will fall across the
Chain but then lose steam as the front weakens bringing light
precipitation to Southwest, with the exception of the Bristol Bay
region receiving moderate precipitation. The entire region will
experience a downward trend in temperatures through this weekend
and into next week as colder air builds in behind the
aforementioned front.

-Sprinkles

&&

.LONG TERM FORECAST (Days 4 through 7: Tuesday through Friday)...

An upper level Western Bering low moves across to the Western
Alaska Coast through the period. The associated long wave trough
sweeps across the Aleutians and Bering before extending over the
Southwestern Mainland into the Gulf of Alaska by Friday. Cooler
temperatures spread over the region with this long wave trough.
Several short waves move through over the Aleutians through the
end of the week, and develop surface lows near the Eastern
Aleutians for both Tuesday and Thursday. Another short wave
supports a surface low over the Western Aleutians Thursday through
Friday. Forecast confidence decreases through Friday with the
transient lows. Periods of locally heavier precipitation and gusty
winds will be the order of the day along the Aleutians and Alaska
Peninsula through the forecast period. Areas of high surf are
possible Tuesday and again Thursday and Friday around Bristol Bay.

In the East, the long wave trough spreads over the Western Gulf
Tuesday night, with a moderately strong surface low sliding past
Kodiak Island Wednesday and Thursday. This brings strong winds
from the Alaska Peninsula to the Southcentral Coast through
Friday. Locally heavy precipitation occurs with the low through
the forecast period, beginning along the coasts and spreading
inland as the low tracks to the Southcentral Coast.

Kutz

&&

.AVIATION...

PANC... Rain continues across Anchorage in response to a front
pushing northward through the area today. Despite temperatures
being above freezing, untreated surfaces that are below freezing
may remain problematic as rain may still freeze upon contact.
Temperatures remaining above freezing through Saturday will help
the surface warm above freezing however. CIGs have remained VFR as
a SE low/mid-level wind component has continued some downsloping
and drying, however MVFR CIG's are possible later this evening
and into Saturday morning.

Winds will generally be out of the SE out of the Turnagain Arm,
though may become light/var at times. A north wind will once again
prevail by late Saturday. Light rain is possible into Saturday,
but downsloping will largely keep it out of ANC.

&&