Gale Warning 414, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
435 PM AKDT Sat Jun 10 2023

.ANALYSIS AND UPPER LEVELS...

A broad longwave trough extends from the Kamchatka Peninsula south
into the North Pacific before turning back to the north and into
the Gulf of Alaska. The main feature of note is a strong low
tracking north to the Alaska Peninsula along the left exit region
of a 90 kt jetstreak. A recent ASCAT pass indicates 40 kt winds in
the cold sector of this intensifying storm. Over the southern
mainland an elongated upper level shortwave is utilizing some
marginal instability to produce areas of scattered showers along
with a few isolated thunderstorms near the Western Alaska Range.

&&

.MODEL DISCUSSION...
Model solutions are in good agreement through Monday and aligned
with the position of the North Pacific low beginning to affect
the Alaska Peninsula/Kodiak Island on tonight. While models
suggest varying strengths of this low, there is high confidence
that widespread gale force winds will impact the marine areas from
the southern Alaska Peninsula to the northern Gulf coast. Gusty
winds and moderate rainfall amounts with this system are set to
also affect land areas along the Southern Alaska Coastline, an
abnormal pattern for this time of year.

&&

.AVIATION...
PANC...VFR under gusty winds and mid-level ceilings this evening
and overnight. As low level winds shift north around 11/11Z, LLWS
is likely as winds aloft remain southeasterly.

&&

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

The relatively cool and moist pattern is set to continue through
the rest of the weekend and into the next work-week. Scattered
showers will continue in the Susitna Valley and western Kenai
Peninsula this afternoon and taper off this evening as a shortwave
trough continues lifting northward through the area.

The well-advertised strong low and front will make it to Kodiak
Island first this evening and bring heavy rain and gusty easterly
winds. The front continues to the north Gulf coast early Sunday
morning and moves inland through the day. This will produce
widespread gale-force winds over the marine areas. There is also
forecast to be a pocket of storm-force winds near the Barren
Islands late tonight into very early Sunday morning. The gales
make it to Prince William Sound Sunday morning through the
afternoon hours as the front pushes ashore. The heaviest of the
rain will be along the eastern Kenai Peninsula/Western Prince
William Sound with Whittier and Portage likely seeing the greatest
amounts Sunday through Sunday night. Although Seward will see
rain, and moderately at times, due to easterly flow in the middle
levels of the atmosphere, most of the precipitation will stay
along the mountain slopes surrounding the area with downsloping
occurring.

Once the front moves inland Sunday night, winds will not be as
strong. However, rain will not end as the upper-level responsible
for sending the strong front into our area is forecast to linger
in the eastern Bering Sea. In turn, flow turns southwesterly in
the middle to upper levels Monday and Tuesday as multiple weak
shortwaves pass over the domain. The result is a continuation of
the showery, cool, and unsettled settled pattern we have been
accustomed to.

&&

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

An fall-like storm system is moving out of the North Pacific
towards the Alaska Peninsula late tonight, tracking north along
the Southwest Coast through Monday evening. Overall conditions
will include strong, gusty winds and moderate-to-heavy rainfall
across Southwest Alaska and the Alaska Peninsula. The Western
Alaska Range, particularly the windward (eastern) side of the
Range, and south along the Alaska Peninsula, will see the
heaviest rainfall. The Bristol Bay region will see some of the
highest winds, with gusts along the coast reaching up to 45 knots
(52 mph) and up to 60 knots (70 mph) further inland. Areas out of
Kamishak Gap will see highest wind speeds. Winds will begin to
subside late Sunday night, though will stay elevated with speeds
18 knots (20 mph) or higher for most areas. Flow will begin to
transition to onshore (south-southwesterly) by Monday morning as
the low continues a northerly track, remaining somewhat elevated
through Tuesday morning. There is still some inconsistency on
Monday with low position, which will dictate where the strongest
onshore winds will be come Monday.

Further west, the Aleutian Arc will see relatively milder weather
conditions as a whole. Showery, with continued cloud cover for
most areas across the Aleutians and much of the Bering Sea.

&&
.LONG TERM FORECAST (Days 4 through 7/Tuesday through
Friday)...

A broad upper level trough remains anchored over the Bering. This
will generate widespread showers across the Aleutians, Alaska
Peninsula, and southwest Alaska through Wednesday. Farther north
over the Arctic Ocean, a strong upper level low extends southward
through Thursday and effectively re-energizes this trough. Would
expect to see continued unsettled conditions for the Bering,
Aleutians and Southwest coast through Friday. Meanwhile for
Southcentral, a weak ridge tries to build over the Gulf on
Wednesday, however is quickly pushed eastward as the upper level
Bering trough advances from the west. An unsettled pattern will
remain as multiple upper level waves traverse Southcentral
through the end of the workweek, keeping showers in the forecast.

&&

SYNOPSIS AND MODEL DISCUSSION...AB/CJ
SOUTHCENTRAL ALASKA...DAN
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KM
LONG TERM...KZ