Area Forecast Discussion
Issued by NWS Anchorage, AK

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34

000
FXAK68 PAFC 150543
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
943 PM AKDT Fri Jun 14 2019

.ANALYSIS AND UPPER LEVELS...

An upper-level low and associated surface low over the North Pac
and Western Gulf situated near 160W is slowly encroaching on the
ridge over the Panhandle and the Eastern Gulf of Alaska. GOES17
Day Cloud Phase indicates low stratus ahead of a weak surface low
west of Sitka drifting north. Radar shows only light and scattered
rainfall outside of Prince William Sound.

Turnagain Arm winds started with gusts in the 30kt range early on.
The Southeasterly shift occurred over western Anchorage by late
morning with winds picking up in the Matanuska Valley shortly
after.

For Southwest, the focus is on the AKPEN with an occluded front
moving over and into the Bering. As is usual, persistent rain,
gusts, and low decks will be norm for the day there.

&&

.MODEL DISCUSSION...

Models were in good agreement through the weekend and only begin
to slip approaching Monday. As the weekend develops, it becomes
more likely that passing disturbances moving out of the Gulf have
more impact over Southcentral, while working against downsloping
flow over the Kenai and Chugach mountains (with respect to Cook
Inlet locations). Coastal clouds and wet weather appears to be a
lock.

Little change is expected over Southwest as the parent low moves
very little from its current position.

The forecast challenge may focus on the spread of any convective
weather possibilities getting the squeeze from a northern
disturbance and the incoming marine environment from the south.

&&

.AVIATION...
PANC...Gusty Turnagain Arm winds will continue through early
Saturday morning. VFR ceiling and visibility are expected
throughout the period.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3/Friday
night through Monday)...

Low pressure in the Gulf of Alaska is continuing its push
northward. Cloud cover and rain have moved into Kodiak, with
rain showers along the southcentral coastline. As the low moves
north, rain showers along the coast will transition to steady
rain overnight tonight. Showery activity will be present inland
with many areas being blocked by the mountains from any rain at
all. The incoming low has also eliminated almost all convective
activity, so it will be quiet when it comes to thunderstorms the
next few days. Some limited action will be present on the south
side of the Alaska Range. The low is also kicking up the Turnagain
Winds today and those should continue intermittently for the next
couple of days. This latest low is expected to exit Sunday and
with the next low entering the gulf on Monday.

When it comes to generating the forecast, models were trending
stronger with winds along the coast, so we increased the wind
speeds with this incoming low. Winds along the coast look to
maintain small craft advisory levels for tomorrow and tomorrow
night. They are expected to die down on Sunday. Otherwise, the
weather looks to be on track so little adjustment was made. We
have high confidence in the forecast through the short term.

&&

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

Weather across southwest Alaska will have to deal with two main
influencers this afternoon and overnight. As we`ve seen over this
last week, the thermal trough and airmass instability will help
to fire off thunderstorms across parts of the Kusko Delta and
Lower Kusko Valley. Meanwhile, low pressure south of the AKPEN
will slowly drift to the northeast. A front associated with this
low will bring increasing showers to the AKPEN. Scattered showers
and clouds will linger Saturday and Sunday. Temperatures will
slowly rise through the weekend, with daytime highs and overnight
lows still 4-10 degrees above the normal for mid June.

&&

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

Low pressure east and south of the eastern Aleutians is the only
significant weather maker through the weekend. Pacific facing
locations east of Dutch will see rain through most of the weekend,
until the low moves far enough away to dry the area out.
Otherwise stable, northerly flow will be ever present across the
rest of the Aleutian Chain and Bering Sea. High pressure will
build across the west as we move into the next workweek,
increasing odds for the summertime stratus across the sea and null
weather.

&&

.MARINE (Days 3 through 5)...

Bering and North Pacific: There is an upper level low south of
the Alaska Peninsula that is slowly weakening and will push
eastward towards the Gulf Of Alaska. Meanwhile, a ridge will build
and also push eastward. This ridge will result in widespread
marine stratus. All of the global models are showing this pattern.
This will be a relatively quiet period for winds and wave
heights. The next chance for an organized mature low impacting the
Western Aleutians will be Saturday June 22.

Gulf Of Alaska: There is a weakening upper level low that will
take residence in the Gulf Of Alaska. Expect some wrap around
moisture lingering showers.

&&

.LONG TERM FORECAST (Days 3 through 7)...

The long range forecast starting on Monday night will be rainy
across the gulf with scattered showers across the southern
mainland as an organized low spins south of Kodiak Island. This
system begins to track slowly east with rain/showers tapering
down. Meanwhile, a ridge builds across the Bering bringing low
clouds and patchy fog with a stable air mass setting up through
mid week. Models continue to struggle on handling the movement of
the Gulf low...so there is fairly high uncertainty Tuesday through
Thursday night for precipitation trends. Toward the middle of
next week...expect drier conditions for much of the southern
mainland with above normal temperatures. The Bering ridge is
expected to break down toward the end of the week as a North
Pacific low pushes to the Western Aleutians while a second low
dives along the west coast.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...DS
SOUTHCENTRAL ALASKA...BJB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...SS
MARINE/LONG TERM...PJS


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.