Gale Warning 727, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
453 PM AKST Mon Nov 14 2022

.ANALYSIS AND UPPER LEVELS...

A quieter weather pattern is developing as a ridge dominates most
of the Bering with northerly winds slowly relaxing today which
has brought temperatures down into the 30s across the Pribilofs
and Aleutians. A low pressure system moving north near Kamchatka
is pushing a frontal system towards the western Aleutians and
western Bering bringing rain and gale force winds. A weakening
surface low across Bristol Bay continues to produce light snow,
with radar trends showing light snow from Dillingham and
northward. Farther south an occluded low is spinning well south
of the AKPen with no impacts to our area. Across Southcentral a
surface trough across the Susitna Valley with associated upper
level shortwave across western Alaska is producing snow across the
northern Susitna Valley and northern parts of the Copper River
Basin as seen on webcams. Radar also indicates showers moving
across Prince William Sound due to some lingering instability.

&&

.MODEL DISCUSSION...

Models in good agreement with a strong ridge building across most
of the mainland this week. Most of the uncertainty this coming
week will revolve around fog and stratus development as high
pressure builds in. Subsequently, this will play a major role in
temperature forecasts in the coming days.

&&

.AVIATION...

PANC...VFR conditions will persist through the period, however
there is a chance of some patchy shallow fog to briefly
develop later this evening through the early morning hours. The
fly in the ointment is the northerly winds will develop tonight
which will either prevent fog from developing or will quickly lift
the fog with possibly some patches of low stratus near the
terminal.

&&

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

Isolated rain and snow showers in Prince William Sound and along
the southern slopes of the Alaska Range, respectively, are waning
this evening as the southerly upslope flow supporting them
continues to weaken and dry air advects in aloft over Southcentral
Alaska. Strong high pressure will build in over mainland Alaska
tonight, reversing the southerly surface flow to northerly, and
putting an end to the remaining shower activity. Dry conditions
will prevail for most of Southcentral as high pressure remains in
place through Thursday. The one chance for precipitation will
come with a warm front tracking northwestward across the Gulf of
Alaska tonight through Tuesday night. The bulk of rain is expected
to remain south over the Gulf and Kodiak Island, with some
potential for upslope rain showers along the north Gulf coast and
particularly the eastern Kenai Peninsula Tuesday night and
Wednesday. Behind the warm front, east to southeasterly flow will
have the potential to feed further moisture to the region, mainly
near Kodiak Island, though where this feature sets up will
ultimately determine the duration of heavy rain along the east
side of the island. Currently, one to two inches of rain is
expected for Tuesday through Wednesday night.

Temperatures will cool back below freezing for Southcentral tonight,
with light northerly winds developing and mostly clear skies.
There is uncertainty with how low temperatures will be able to
reach over the next several days as conditions conducive for fog
develop. Warm air advection kicks in through mid week as an upper-
level ridge becomes centered just to the east. Expect
strengthening temperature inversions as temperatures warm more
aloft than at the surface, leading to an increased likelihood of
fog as we progress through the week. For the northern Cook Inlet,
tonight looks to be the most favorable for fog with northerly
winds at their weakest for the next few days, limiting the ability
for fog/stratus to be mixed out. Northerly flow strengthens through
Cook Inlet for Tuesday night, when the high pressure over the
Interior is forecast to be most intense, suggesting low potential
for fog/stratus. In the Copper River Basin, conditions appear more
favorable each night with light and variable winds forecast
through Thursday.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3: Tonight
through Thursday)...

Expect colder and drier conditions tonight and tomorrow. Then,
temperatures and precipitation chances increase for Wednesday and
Thursday. For tonight, a shortwave trough may bring some light
rain and snow showers to Bristol Bay and the Alaska Peninsula. As
this shortwave weakens and a ridge moves east into Southwest
Alaska, skies will gradually clear. Effective radiative cooling
will lead to colder nighttime temperatures and the potential for
fog early Tuesday and Wednesday mornings, especially in the Lower
Kuskokwim Valley. Over interior Bristol Bay and the Kuskokwim
Delta, brisk northeasterly winds should help keep the fog at bay.

Higher pressure will keep skies relatively clear for most of
Tuesday. By late Tuesday night into Wednesday, a shortwave moves
from the the North Pacific Ocean into the Bering Sea. This will
orient the flow more southeasterly over Southwest, bringing a
surge of warm air and moisture. Most of the precipitation will be
limited to southeasterly faces of the Alaska/Aleutian Range and
Kuskokwim Mountains, with lower elevations staying mostly dry due
to downsloping. This is good news because the initial surge of
warm air aloft, combined with colder surface temperatures, could
otherwise lead to light freezing rain on Wednesday. Freezing rain
is not out of the question, but any ice accumulations are expected
to be minimal.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3:
Tonight through Thursday)...

A low near the Kamchatka Peninsula will slowly push its front
eastward across the Bering Sea through Wednesday. Winds along the
front are expected to be gale force, with embedded areas of storm
force winds. Light to moderate rain along the front is expected to
intensify by early Tuesday morning over the Western and Central
Aleutians as a weak tropical system is absorbed into the front.
From Wednesday through Thursday, the front and its winds will
slowly weaken as it runs up against high pressure over Mainland
Alaska and stalls.

The Eastern Bering Sea, Eastern Aleutians, and Pribilof Islands
will be mostly spared from the aforementioned front. Instead, the
primary weather maker for this region will be a North Pacific low.
Northeasterly winds tonight over the backside of the low will
gradually become southeasterly on Tuesday afternoon as an upper
level shortwave moves from the North Pacific into the Bering Sea.
This shift towards southeasterly flow will bring increased
temperatures and rain/snow chances for Wednesday and Thursday.

&&

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

A persistent ridge of high pressure will stretch across much of
the Mainland through the long term. This will promote generally
benign conditions across Southcentral through Sunday. Deep
southerly flow with the ridge will result in above average
daytime high and overnight lows are advertised for both
Southcentral and Southwest Alaska through the weekend. Upper-level
shortwaves within the upstream ridge flow will track across
Southwest Alaska and maintain periods of precipitation through
Saturday morning. Meanwhile, an upper-level low and its associated
surface low are expected to move into the Gulf of Alaska. At this
time, precipitation and winds accompanying the aforementioned low
and front look to stay confined to the Gulf waters through
Monday.

Out west, an upper-level trough located over the Bering on is
expected to lift northeast towards the Bering Strait by Friday
morning. Precipitation will subsequently clear across the Bering
with the exit of the trough and the development of a shortwave
ridge. Any respite from precipitation across the Bering will
likely be short lived as a front extending from a North Pacific
low is expected to reach the western Aleutians Friday morning and
track into the Bering through the weekend. Model spread grows in
association with the exact track and strength of the low and its
front, but a consensus of widespread rain and gale force winds are
currently advertised to accompany the low. Current GFS model runs
are advertising the aforementioned low tracking northward across
the Alaska Peninsula and into the eastern Bering with widespread
gale force winds located in the western and central Bering.
Meanwhile, recent Canadian and EC runs are showing the track more
eastward towards the Gulf with a swath of small craft winds
roughly located over the eastern Bering.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gale 130 131 132 138 150 155 175 176.
		 Storm 177 178 185.
		 Heavy Freezing Spray 160.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...RC
SOUTHCENTRAL ALASKA...CQ
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KC
LONG TERM...NS