Gale Warning 429, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
506 AM AKDT Tue Jul 26 2022

.ANALYSIS AND UPPER LEVELS...

A 120 kt jet streak is draped southwest-northeast across Eastern
Alaska. With the jet streak continuing to track eastward, a low
near the Seward Peninsula is now unfavorably located in the jet
streak's left entrance region. As such, the low is weakening and
occluding as it moves north into the Chukchi Sea. The occlusion is
visible on satellite imagery, where cold air wrapping around the
low center is forming a notch of lower clouds in the Interior.

With the low weakening, winds have largely decreased since
yesterday. Gusty winds are still present in the Anchorage Bowl,
with peak winds hovering around 30 kt this morning. Otherwise, rain
is petering off and skies are clearing across Southcentral Alaska
as upper level shortwaves move out of the region and higher
pressure builds in. Dynamic forcing associated with these
shortwaves led to overnight showers along the Chugach Front Range
and into Matanuska Valley. The overall wettest conditions,
however, occurred in Prince William Sound, with Cordova recording
a 24-hour rain total of 1.58 inches. As seen on Bethel radar,
rain showers continue to occur across Southwest Alaska as cold
air streams in aloft.

&&

.MODEL DISCUSSION...

Models remain in excellent synoptic agreement. There is high
confidence in fairly benign weather as a ridge builds over the
Southern Mainland through Wednesday. Though a low will move into
the Gulf from Wednesday through Friday, confidence is increasing
that there will be little, if any, impact of this system on
Southcentral. Agreement is slightly worse, but remains fairly good
overall, with a low that enters the Bering Sea from the North
Pacific Ocean late Wednesday. Global models display excellent
agreement with the low's strength but show minor differences in
the track of the low. This will impact precipitation timing as the
front enters Southwest Alaska late Thursday.

&&

.AVIATION...

PANC...VFR conditions will persist through Wednesday. Gusty
southerly winds, peaking around 30 kt, will slowly diminish
through the morning. Confidence is high that winds will drop to
10 kt or lower by the afternoon as a ridge moves in.

&&

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

After a period of blustery and showery weather yesterday due to
the lower pressure system spinning near Kotzebue, things look to
take a turn to the quiet side as showers continue to taper off
around Prince William Sound with just left over upslope showers
over the favored terrain. Pressure gradients and subsequent
surface winds will also relax as pressure heights build into the
Gulf of Alaska. Also helping to usher in quieter conditions is the
northward retreat of the polar jet.

For tonight, expect some chilly overnight temperatures as 850mb
temperatures are between 2-4 degrees Celsius. This is especially
true for parts of the Copper River Basin where temperatures could
dip into the middle 30s. Expect mostly dry and sunny conditions
for the next few days as mid to upper level ridging noses in from
the southwest.

With progressive upper level flow, a low will track out of the
North Pacific into the Gulf of Alaska over the next couple days.
Confidence has greatly increased that this system will remain over
the Gulf, with little to no impact on Kodiak Island and Southcentral.

&&

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

Conditions continue to improve across Southwest as the system
departs to the north. Temperatures will stay cool in the 50's for
one more day before increasing again on Wednesday. Increased
winds will continue through the early morning hours today, and
into the afternoon for the Kuskokwim Delta. Light rain showers may
linger across Southwest today, but will mainly be along the
higher elevations. Overall, expect conditions to dry out and
clear up over the next couple of days.

&&

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

High pressure resides over the Bering today, resulting in
relatively mild conditions overall. Expect the usual areas of
patchy fog and low marine stratus that usually accompanies areas
of high pressure across the Bering. Tonight, the front off a North
Pacific low pushes over the Western/Central Aleutians before
moving further into the Bering. This system is weaker than the
previous, unseasonably strong low, but anticipate gale force winds
and substantial rainfall along the front.

&&

.MARINE (Days 3 through 5: Thursday through Saturday)...

Gulf of Alaska: A departing low over the southern Gulf on
Thursday will move into Southeast Alaska through the course of the
day. In its wake shortwave ridging will overspread the region
before exiting east on Saturday. Confidence remains high in benign
conditions prevailing Thursday into Saturday with seas below 20
feet and winds well below gale speeds. The next low begins to move
into the western Gulf on Saturday, which could see increasing
winds into the Shelikof Strait.

Aleutians/Bering: All models are in good agreement with bringing
a broad upper trough and surface front over the southern Bering
Sea and Aleutians Thursday into Friday. Unsettled conditions will
accompany the trough’s progress with potential south to
southeasterly gales along the front from the Eastern Aleutians to
the Pribilofs on Thursday. The front begins to weaken on Friday
while continuing eastward into the Alaska Peninsula. By Saturday
the weakening parent low lifts northward somewhat while the triple
point low and front shift into the Gulf. This should leave the
region somewhat quieter on Saturday. Seas are expected to remain
below 20 feet through the period.

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

General high pressure and benign weather conditions across
Southwest are expected to slowly come to an end by Friday with
models picking up on the next North Pacific Low moving into the
Bering Sea as early as Thursday. A vertically stacked low will
start the morning on Friday west of the Pribilofs. Its associated
front will make eastward progress across the Aleutians with areas
of scattered showers and potentially gusty southeast winds from
the Central Aleutians into the Alaska Peninsula. Additionally,
there are some indications that a triple point low will develop
along the front and over the Alaska Peninsula, which would further
enhance shower activity moving into Southwest during the evening
hours on Friday. Further east and over Southcentral high pressure
is expected to linger a bit longer with one more day of clearer
skies and warmer temperatures on Friday. However, the
aforementioned front and developing area of low pressure are
progged to shift into the western Gulf on Saturday with increasing
showers lifting into Cook Inlet, Prince William Sound and the
Gulf Coast. Whether or not moisture and rain activity can make it
further inland remains to be seen, but increasing cloud cover and
cooler temperatures can be expected over the weekend for
Southcentral. Meanwhile, the southern Bering Sea and Southwest
will remain in favorable upper level flow for additional low
pressure disturbances to track across the region with bouts of
light showers possible. Models are a bit more uncertain into the
start of next week. Current guidance suggests high pressure will
attempt to amplify over Southcentral as a broad trough begins to
take shape over the Bering Sea. Drier and warmer conditions across
Southcentral would ensue while increasing clouds and shower
activity spread from the southern Bering Sea into Southwest
through the course of Monday.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...Gale Warning: 175-177.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...KC
SOUTHCENTRAL ALASKA...DAN/SEB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KM
MARINE/LONG TERM...BL