Gale Warning 981, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
408 AM AKST Sun Dec 29 2024

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

As of this morning, fog persists across parts of the Anchorage
Bowl and the Knik Arm under light northerly flow. Nighttime
Microphysics imagery shows the fog footprint gradually shrinking
across the area owing to the infiltration of drier air and light
low-level mixing. Fog and/or low stratus also continues to plague
the southern portion of the Copper River Basin with persistent
fog/stratus noted along the Edgerton Highway and McCarthy Rd, as
well as in the western basin closer to Tahneta Pass.

Upper-level ridging will shift eastward across much of Alaska
today, resulting in mostly quiet weather across the forecast area.
Mostly clear skies are expected for areas not impacted by the
aforementioned fog/stratus. Gap winds have already decreased since
yesterday and will continue to do so, with the strongest winds
remaining out of the Copper River Delta and out of Valdez and
Thompson Pass. Blowing snow may continue to be an isolated threat
today near the pass in areas where there remains transportable
snow. Webcams along the Richardson Highway haven't shown much
overnight in terms of visibility issues / blowing snow, which may
suggest the thread has ended. Still, please continue to use
caution if traveling in that area today.

Southeast flow will ramp up today across the western Gulf of
Alaska, including Kodiak island, in response to a deep low lifting
into the eastern Bering Sea and its associated front pushing
eastward. Cloud cover is expected to deepen across Kodiak Island,
with upslope snowfall across the island's mountains. Kodiak City
is likely to experience an increase in shower coverage this
evening into tomorrow, with any precipitation likely to begin as
snow before quickly transitioning to rain with the onset of warm
onshore flow.

Moist southeast flow will also bring about an increase in
cloudiness and precipitation to the eastern Kenai Peninsula
tonight into tomorrow. Most precipitation should remain off the
road system, though can't rule out Seward and even Whittier-
Portage receiving some light precipitation. Snow levels are likely
to remain as sea level, though light onshore flow may push
temperatures up just enough for a rain/snow mix along the
immediate coastline.

By Tuesday, a northward moving low is expected to bring heavier
rain (high elevation snow) to Kodiak Island, along with widespread
gale- and storm-force winds into much of the Gulf of Alaska. This
low pressure is expected to turn towards the northwest by
Tuesday, which will keep most precipitation out of southcentral AK
with the exception of the southern/western Kenai, as well as
Kodiak Island.

-Brown

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

Winds across the Eastern Aleutians and southern Alaska Peninsula
have picked up over night as a storm force low approaches the
Chain. The low has shifted just slightly west, allowing
Unalaska Island and Unalaska Bay to see higher winds than
previously anticipated, with gusts up to 65mph possible. Gusts to
80mph is likely along the southern AKPen, with Cold Bay being
particularly susceptible to these high winds today. A High Wind
Warning has been issued, persisting early this morning into this
evening. As the low tracks northwards, the core of storm force
winds will push across portions of the eastern Bering Sea and
Pribilof Islands, with widespread gale force winds elsewhere
across eastern/central Bering. Additionally, wind gusts upwards of
45 mph near the Kuskokwim Delta coast through Monday allow for an
increased potential for periods of blowing snow and elevated
storm surge, mainly near Kwigillingok.

For interior Southwest, conditions will remain mostly calm as a
ridge over most of mainland Alaska keeps the active weather to the
west. The western Aleutians/Bering will experience periods of
rain and snow showers through Tuesday due to the Kamchatka low and
a North Pacific low south of Shemya sending weak fronts over the
area.

&&

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

The New Year starts with an upper level tilted ridge building
across the Mainland into eastern Russia by the weekend. This
leaves much of the Interior in a dry and persistently easterly
windflow surface pattern. This extends into an area of gusty winds
that will push across the northern Bering through the period.
Farther south, an upper level trough that extends over the
Aleutians and Bering and across the Gulf of Alaska lingers through
the forecast period. The jetstream support for the main cyclone
tracks will also remain well South of the Aleutians and Gulf into
Saturday.

Nearly all of the Southern coastal portions of the state will
continue with scattered areas of snow, rain and snow mixed or rain
through Thursday. As the surface lows and fronts track Eastward
from the South of the Central Aleutians and Alaska Peninsula, over
Kodiak Island to the Southcentral coasts, precipitation areas
will be brief with little to no accumulation. Gusty easterly
winds will occur Wednesday and diminish Thursday across the
Northern Gulf, around Kodiak Island and straddle the AKPEN into
the Eastern Aleutians. Friday brings a low north from the Eastern
North Pacific, and spread more moderate snow or rain and snow from
the Eastern Kenai Peninsula over Prince William Sound to the
Canadian border. A new system pushing out of Eastern Asia Friday
exerts its influence with more moderate rains over the Aleutians
through Saturday. Gusty winds increase to gale force over the
Western Aleutians Thursday, slowly diminishing and spread all the
way to around Kodiak Island and AKPEN and across the Bering
through Saturday.

&&

.AVIATION...

PANC...Patchy dense fog may linger in the vicinity of the
terminal through Sunday morning, VFR ceilings are expected to
prevail. Winds will increase and shift slightly to the east
overnight. This shift should cause any fog to retreat over Cook
Inlet and away from the terminal.

&&