Small Craft Advisory 279, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
442 AM AKDT Mon Apr 3 2017

.ANALYSIS AND UPPER LEVELS...

A strong closed upper level low is located well south of Kodiak
Island this morning, with a rapidly weakening low west of Bristol
Bay. A third low is over northern Kamchatka. Upper ridges are over
the Bering, and the eastern Gulf and southeast coast. At the
surface, a deep low south of Kodiak and its associated front are
approaching the southwestern Gulf, while the low west of Bristol
Bay is dissipating. The third low is moving off the Kamchatka
Peninsula into the western Bering.

&&

.MODEL DISCUSSION...

Models are in agreement that the main low will reach the
southwest Gulf overnight with a wave moving along the north Gulf
Coast this morning, followed by a front tonight. The original low
will weaken in place and another low will sweep into the Gulf Tue
night, with weak fronts reaching the coast Wed. The remnants of
the low west of Bristol Bay will dissipate this morning, and the
Kamchatka low will reach the southern Bering before dissipating
early on Thu. The forecast was freshened with the higher
resolution solution of the gfs.

&&

.AVIATION...
PANC...VFR conditions are expected to persist through Tue
morning. Northwest surface winds will increase in response to a
front moving inland this evening through early Tue morning.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
A low pressure system is entering the southwest Gulf this
morning. A front preceding this low pressure system will bring a
very potent front across the Gulf coast with storm force winds
likely across much of the Gulf of Alaska on through tonight along
with Shelikof Strait, the Barren Islands, and the northern Gulf.
Much of the precipitation will fall along the Gulf coast and
coastal mountains. Sufficient cross barrier flow will keep much
of inland Southcentral Alaska on the dry side. Temperatures will
remain a bit warmer than normal as the source region for the air
mass with this storm is from the south.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
Low pressure across the Kuskokwim Delta diminishes by this
afternoon as it moves into the eastern Bering. The next low from
the North Pacific pushes a front into the Alaska Peninsula early
today bringing strong gusty winds along the peninsula. The
associated low center moves to the south end of Kodiak Island
tonight which pushes the front across the southwest. Easterly
flow along the mountain ranges limits precipitation inland as the
front moves across the Aleutian Range with the best chance to see
light accumulations along west facing slopes. The upper low
meanders near Kodiak through mid week keeping higher chances of
precipitation in the short term forecast. A re-enforcing surface
low on Tuesday night brings another surge of moisture from the
eastern gulf to the Alaska Peninsula and Bristol Bay.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
The eastern Bering and Aleutians can expect winds to increase out
of the north today as a North Pacific low nears the Alaska
Peninsula. Snow will continue to develop across the eastern half
of the Bering as an upper trough remains the dominant weather
pattern through Wednesday. Surface ridging along the western
Bering shifts south across the Central Aleutians today keeping the
area under a lighter flow pattern. Weak low pressure follows in
its wake tonight bringing light snow showers across the western
waters with a westward shift in winds.

&&

.LONG TERM FORECAST (Days 3 through 7)...
The active pattern looks to continue for much of this week with
the low in the Gulf being reinforced with another low pushing up
from the south by Wednesday. This will keep warmer air being
ushered in over the southern mainland and rain along the north
Gulf coast. Late in the week the low looks to track into the
eastern Bering which could clear out some of the precip for
Southcentral Alaska. However, guidance is struggling with what to
do with the low as it moves into the Bering and how ridging will
set up for the weekend. These differences could lead to fairly
significant differences for what kind of weather the southern
mainland will see. The most consistent guidances are the ensemble
means which were preferred for next weekend.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Storms 119 130 131 138
         Gales 120 125 132 136-7 139 150 155 160 172.

&&

SYNOPSIS AND MODEL DISCUSSION...ds
SOUTHCENTRAL ALASKA...bl
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...kh
LONG TERM...dk