Gale Warning 206, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
538 AM AKST Mon Mar 3 2025

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

Southeasterly flow aloft will continue to pump warm and moist air
over Southcentral Alaska today. This is due to a highly amplified
upper level ridge over British Columbia and an upper level trough
extending from the Alaska Peninsula southeastward and undercutting
the Gulf of Alaska. This trough is coming into better focus as models
have now come into good general agreement that it will develop
into a cut-off low south of the Gulf this afternoon and then track
southeastward into Tuesday. As this first low moves Southeast, it
will give way to a more significant upper level low in the Bering
Sea which will move toward the Gulf Wednesday into Thursday.
There are a number of ways this might unfold with the main
question being how far east this second low moves. Compared to the
GFS, the ECMWF model is farther to the east by Wednesday night.
This pattern will continue with the GFS being farther west with
the surface low than the ECMWF or the NAM for Wednesday and
Wednesday night. These differences will determine whether the
north Gulf coast will reach Storm force winds or remain Gales with
the barrier jet developing north of the low. It also will impact
the chances of any precipitation for Southcentral for the midweek
period. Either solution will likely bring coastal rain and
mountain snow to the eastern Kenai Peninsula. However, the GFS is
the only model to give a chance of precipitation for the Western
Kenai Peninsula through Anchorage and into the Mat-Su when the
upper level trough lifts northward through the area. For this to
happen, the trough would have to align just right with its timing
and the moisture associated with the surface low which will be
dissipating as it moves inland. While this is possible, the more
likely scenario is for the cross-barrier flow to win out and
downslope out the precipitation for the Western Kenai and
Anchorage areas, as well as farther north into the Mat-Su.

The airmass currently over Southcentral is quite a bit warmer
aloft than the air that will move through with this midweek
trough. Therefore, expect mild temperatures through mid week with
a cooling trend after the trough goes through.

&&

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

Overnight through 5:00AM today: Temperatures remained in the
upper 30s and scattered rain showers were common across the AK Pen
and Bristol Bay coast. Farther north in the Kuskokwim Valley,
temperatures cooled into the upper teens/lower 20s despite
continued southerly wind flow and a mostly cloudy sky. Northerly
winds, gusting as high as 30 knots, continued to bring rounds of
snow showers from Nelson Lagoon to Dutch Harbor with temperatures
holding in the lower 30s.

A weak low pressure system continues to move over the AK Pen and
through Bristol Bay through the day today bringing another round
of scattered rain showers to the region. As the low moves through
Bristol Bay, the rain mixes with snow. Snow overspreads the
Kuskokwim Delta as the low moves northward over coastal SWAK. A
brief period of dry conditions return in the wake of this low
continuing through tomorrow morning for SWAK and the AK Pen.

Northerly winds will continue to bring snow showers to the
Central Aleutians today as a trough moves across the Bering and
the SWAK low moves northward. Temperatures remain in the lower
30s, too.

A stationary low southwest of Shemya impacts the Western and
Central Aleutians through tomorrow evening bringing storm to gale
force winds. Its front becomes elongated Tuesday resulting in
multiple weak lows forming and causing continuous waves of
rain/snow through mid-week.

&&

.LONG TERM FORECAST (Days 4 through 7 - Thursday through
Sunday)...

The high amplitude upper level ridge extending over Southeast
Alaska and Western Canada will continue to be pushed east as broad
upper troughing moves in from the Bering Sea and Western Alaska.
A generally unsettled pattered will kick off the long term period
with relatively good model agreement in the upper levels of the
atmosphere and more uncertain surface features locally enhancing
the weather. A surface low supported by Pacific moisture and
troughing aloft will bring a round of moderate precipitation to
Prince William Sound on Thursday before moving on towards the
Panhandle later in the week. Northerly flow on the backside of the
low will bring in colder air and could cause gusty winds through
bays and passes of the Eastern Aleutians and Alaska Peninsula.

Upper ridging will track across the Bering Sea Friday and
Saturday, quickly being followed by another low pressure system.
Drier conditions are expected for Southcentral to start the
weekend as high pressure moves over the state. The low following
the aforementioned ridge will likely bring widespread
precipitation and gusty southerly winds to the Aleutian Chain as
it marches eastward, but there is still uncertainty about the
low's strength at this time. Most of Alaska will continue to see
warmer than normal temperatures for the next week, with cooler
temperatures possible by the weekend as northerly flow comes in
behind the trough.

&&

.AVIATION...

PANC...VFR conditions will persist throughout the TAF period.
Wind speeds at the surface are expected to remain light and
northerly through the TAF period. There is some uncertainty about
low level wind shear, but the current thinking is that elevated
southeasterly winds will generally remain above 2000 ft.

&&