120
FXAK68 PAFC 090102
AFDAFC
Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
502 PM AKDT Thu May 8 2025
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)...
Decaying low pressure in the Gulf of Alaska and the exiting of an
interior shortwave are allowing for decreased shower activity
this afternoon across Southcentral AK. The upper Susitna Valley is
expected to hold on to precipitation and low clouds the longest,
but it too should see a clearing trend as flow shifts northerly
tonight. A shortwave trough looks to swing up the Panhandle into
the northeastern Gulf by Saturday morning, increasing wind speeds
and precipitation chances for the coast, primarily around the
Copper River Delta and eastern Prince William Sound. Later
Saturday into Sunday could bring a chance for precipitation
farther inland along the Richardson Highway and east for the
eastern Copper River Basin as a weak shortwave trough concurrently
dips across the eastern Alaska Range toward the Al-Can border.
High pressure building in from the west will produce overall
pleasant conditions for most of the region through the weekend,
where light winds, partly sunny skies, and high temperatures in
the low 60`s are forecast.
&&
.SHORT TERM FORECAST SOUTHWEST ALASKA AND BERING SEA/ALEUTIANS
(Days 1 through 3)...
The main short-term items to keep an eye on will be the potential
for afternoon showers near the Aleutian Range and Alaska Range.
This includes a slight chance for a thunderstorm north of Iliamna
and toward the middle-to-upper Kuskokwim Valley. The next
questions will be whether the Bristol Bay region goes down in fog
late tonight/early Friday morning with the clearing skies after
the afternoon/evening showers subside. At this time, it looks less
likely for the widespread fog from this morning to re-develop as
the flow will be more easterly and less southerly which should
help limit the overall low-level moisture.
In general, mainland Southwest Alaska will remain mostly quiet over
the next couple of days with the exception of some diurnally
driven showers in the areas mentioned earlier. The driest day
across the southwestern mainland looks to be Saturday as a drier
airmass moves overhead.
Models are coming into better agreement with the track of the
storm moving into the Bering Sea Sunday into Monday. The most
likely track looks to take this low over Atka and then west of the
Pribilofs. This will likely put Unalaska to Sand Point into some
strong southeasterly winds in advance of the low on Sunday.
&&
.LONG TERM FORECAST (Days 4 through 7/Monday through
Thursday)...
An amplified upper-level low spans from the Bering Sea to
Southeast Alaska. Strong southerly flow and ample moisture will
bring steady precipitation across the Alaska Peninsula on Monday
morning and the Panhandle by Tuesday morning. Unsettled weather
will continue across Southwest on Tuesday as a second system
crosses the central Aleutians and lingers in the Bering Sea, and
again on Wednesday for Southcentral when a triple point along its
front sweeps across the Gulf on Wednesday to reach the Southeast
part of the state by Thursday morning.
&&
.AVIATION...
PANC... Westerly to southwesterly winds will become more northerly
and decrease with loss of diurnal heating and sea-breeze effects.
Scattered showers will also dissipate with loss of heating. High
pressure over much of Southcentral will help to limit showers on
Friday, but may increase chances for areas of fog after 12Z
Friday. Models are also hinting at fog developing along the Knik
Arm and working southwards towards the terminal. However, given
the uncertainty, have left mention of fog out of the 00Z TAF.
&&
$$
902
FXAK69 PAFG 082335
AFDAFG
Area Forecast Discussion
National Weather Service Fairbanks AK
335 PM AKDT Thu May 8 2025
.SYNOPSIS...
Most snow over the Alaska Range will be coming to an end by this
evening, with most accumulations focused west of the Parks
Highway. Elevated terrain locations in the Interior will see
chances for showers during the daytimes this week which will be
driven by solar heating. A low pressure area over the Arctic
will lead to moderate westerly winds over the eastern Arctic
Coast which could lead to some blowing snow. Generally warmer
weather is expected from today into early next week across the
Interior ahead of a low moving into the Bering Sea, which will
usher in some more unsettled weather.
&&
.KEY WEATHER MESSAGES...
Central and Eastern Interior...
Some residual snow over parts of the Alaska Range, mostly west
of the Parks Highway, will be ending by this evening.
Elsewhere, some showers and perhaps an isolated thunderstorm
will be possible, especially in the terrain.
- Snow in the Alaska Range, mostly in remote parts west of the
Parks Highway, should end by tonight.
- There will be chances each day for showers in the higher
terrain areas of the Interior. Any showers that form will be
driven by daytime heating and will mostly fade away overnight.
- Isolated thunderstorms among these showers will also be
possible each day over the southeastern Interior, especially
east of Delta Junction.
- Temperatures warming into the upper 50s and 60s expected from
today into next week.
West Coast and Western Interior...
Light rain showers and perhaps an isolated thunderstorm are
possible today in the Norton Sound area. Warmer temperatures are
likely through the weekend.
- Light rain showers today over the YK Delta and Norton Sound
areas.
- Isolated thunderstorms during the daytimes over the Kuskokwim
and Lower Yukon Valleys.
- Temperatures across much of the West Coast and Western
Interior rise into the 50s by Friday.
North Slope and Brooks Range..
Extensive cloud cover and fog is expected to continue on the
Arctic Coast, especially in areas to the east. West winds south
of an Arctic low will pick up over the eastern Arctic Coast
this weekend.
- West winds sustained into the 20 to 30 mph range, with higher
gusts, are possible over the eastern Arctic Coast this
weekend with low pressure well to the northeast.
- Snow will be possible Saturday into Sunday across most of the
Arctic Coast and could exacerbate any blowing snow where it
combines with the stronger west winds. Visibilities below one
mile are not expected to be widespread at the current time.
&&
.FORECAST ANALYSIS AND DISCUSSION...
A 530 dm upper-level low is focused south of St. Lawrence
Island, and rain will be possible along its northern periphery
through Friday. A vertically-stacked 533 dm upper-level low
over the Gulf of Alaska is colocated with a 1008 mb surface low.
Much of the Interior, especially in the higher here will be
additional chances for isolated thunderstorms in the southeast
Interior each day during the daytime. A 519 dam low on Monday
will bring a broad area of precipitation, mostly rain, to the
West Coast, with lesser totals possible in the Interior on
Tuesday and Wednesday. Most of the highest winds with the low
will likely remain offshore, although some general east winds
across Northern Alaska are likely.
&&
FIRE WEATHER...
Much warmer is expected across the Interior and much of the West
Coast from Friday into next week, when widespread 50s and 60s
will be likely. Minimum relative humidity values in the upper
20s and 30s today will continue through the weekend, with
periods of lower 20s possible in the Middle Tanana Valley on
Sunday. Isolated thunderstorms are possible each day this week
in the southeastern Interior as well as in the Kuskokwim and
Lower Yukon River Valleys during the daytime. Brief gusty winds
are possible from any showers or thunderstorms that form. Sunday
will see west winds pick up over the Interior south of a low
pressure center in the eastern Brooks Range. Valley locations
could see sustained winds in the 10 to 15 mph range with higher
gusts, with higher winds possible in the higher terrain.
&&
.HYDROLOGY...
The Yukon River at Ft. Yukon broke up Tuesday with minor
flooding from an ice jam that released overnight into Wednesday
morning. The breakup front remained stalled at 6 Mile Island
below Ft. Yukon as of early Wednesday afternoon while water
levels have continued to drop at Ft. Yukon. The water that has
been carrying the breakup front has continued downstream and is
helping to lift and shift the ice between Ft. Yukon and Beaver;
however without a pulse of water from upstream breakup may be
slowed for a few days. The timing of the breakup front reaching
Stevens Village and the Dalton Highway bridge could be anywhere
from 1-5 days. The River Watch team plans one more flight to
this reach on Thursday to monitor the progression and will
provide updates as information becomes available.
Visit http://www.weather.gov/aprfc for the latest river updates.
&&
.EXTENDED FORECAST DAYS 4-7...
Unsettled weather is expected across much of the area early
next week as a vertically-stacked low moves into the eastern
Bering Sea. While there are some model differences in the exact
timing and placement of the low, there is general agreement a
front sweeping across the area, with a broad area of rain along
the front. The 12Z GFS has the broadest and heaviest rain, with
up to several tenths of an inch of liquid possible in the YK
Delta and Lower Yukon River Valley, with lesser totals possible
across most of the Interior. The 12Z ECMWF solution still yields
some heavy rain in Western Alaska but is more constrained on
precipitation in the Interior, and the same holds for its
ensemble mean. While there will be elevated winds, mostly in the
20 to 30 mph range, the highest winds are likely to remain
offshore. The YK Delta could still see south winds pick up to
over 20 mph on Monday before the low moves out of the area.
General east winds across the area are also likely.
Coastal Hazard Potential Days 3 and 4...None
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
AK...None.
PK...Heavy Freezing Spray Warning for PKZ854.
&&
$$
DS
307
FXAK67 PAJK 082334
AFDAJK
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
334 PM AKDT Thu May 8 2025
.SHORT TERM...An active weather pattern will continue as short
waves rotating around a slowly decaying vertically stacked low in
the central gulf continue to move across the panhandle through
the duration of the week. While a respectable amount of rainfall,
given the current time of year is anticipated, no flooding is
expected.
In particular, two separate waves arriving on Friday look to
provide the greatest impacts to SE AK. The first of these will
arrive through Friday, moving up from the S, bringing with it
fresh to strong breezes across the central inner channels along
with a wave of precipitation across the panhandle. The second wave,
arriving Friday afternoon through Friday evening, will bring with
it similar conditions, albeit with winds along the outer coast
reaching near gale force.
The rainfall will continue through the first half of Saturday,
until a weak frontal boundary associated with the second wave
advances E across the panhandle, bringing drier weather in its
wake. For additional details, see the long term forecast
discussion.
.LONG TERM...Much better consensus between ensemble members regarding
timing and location of heaviest rain rates for the central and
southern panhandle. Saturday will see the final of multiple waves
moving up along the front in the eastern gulf. An embedded wave will
be near Prince of Wales Island, and push into the Yukon over the
morning hours. Associated with this wave will be moderate to heavy,
with rain rates maximizing around 0.1 inches per hour. Southerly
winds look to remain steady at around a fresh to strong breeze in
the very early hours of Saturday. Behind the wave moving northward
is a weak cold front in the eastern gulf, which is expected to move
to the east slowly over the course of Saturday. In the post frontal
environment, winds and rain are expected to diminish quite rapidly.
Good confidence that the cold front will push as far east as
Petersburg down to Hydaburg, but some solutions are keeping the
moisture tap over the southern panhandle well into Saturday
afternoon. While dynamics aloft do not look to support heavier
rainfall beyond Saturday afternoon, lingering rain in the area may
continue into Saturday Night.
Sunday will see the first day in southeast Alaska with widespread
clearing skies and warmer temperatures. Skies look to clear from
northwest to southeast, so areas in the southern panhandle will
likely see clearing later in the day. Expect temperatures in the mid
to upper 50s with some areas possibly exceeding 60 degrees.
For Monday, a shortwave aloft looks to come racing across the
northern gulf, associated with a broad upper level low in the Bering
Sea. An associated surface low will extend a fast moving front over
the panhandle, bringing more rain and wind to the area. Not
expecting winds higher than a fresh breeze, mainly for the Icy
Strait area and north. Main area of concern would be the quickly
dropping pressure in northern B.C. and pressure rises behind the
front could bring up to stronger winds of 20-25 knots to northern
Lynn Canal, Taiya Inlet, and Skagway. .
&&
.AVIATION...Current VFR ceilings will lower this evening for the
central and southern panhandle to MVFR. Prevailing MVFR conditions
will then continue through Friday with ceilings decreasing to
1500 ft and visibilities as low as 4SM. LLWS over the southern
panhandle will begin tonight as the next wave moves north. By
Friday morning, parts of the central panhandle also begin to
experience LLWS. At that time, Friday morning, widespread wind
shear of >25 kts will be located across areas south of Icy
Strait.
&&
.MARINE...Outside Waters: Wind speeds along the outer coast build
up to 25 kt by late Thursday night into Friday morning, while a
second short wave moving N later in the day on Friday brings
sustained winds up to 30 kt. up to 35 kts. Wave heights will
remain around 8 ft before building late Thursday night along the
southern coast to around 10-11 ft. Conditions will rapidly improve
on Saturday in the wake of a frontal passage associated with the
second short wave.
Inside waters: Winds in most of the inner channels Thursday
evening remain around 10 to 15 kt out of the S, before increasing
Thursday night into Friday as the next wave approaches, reaching
20 to 25 kt. Elevated winds then last through Friday and into
early Saturday before rapidly diminish through late Saturday
morning and into Saturday afternoon. The exceptions will be
Clarence Strait, which is already at 25 kt from the S as of late
Thursday afternoon and which will remain so until early Saturday
afternoon. Conversely, Lynn Canal will become variable Thursday
night before flipping out of the N on Friday, and only going S
Friday night.
&&
.HYDROLOGY...Two separate shortwaves embedded within a decaying
frontal band will bring with them 1"-2" across much of the area
Friday through Saturday. Although no flooding is expected, river
rises are likely, particularly for the southern panhandle and
outer coastal areas - locations which could potentially see in
excess of 2 inches, should sufficient S to SE flow in the lower
levels prove to be present. Higher totals are also possible at
elevation.
&&
.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Gale Warning for PKZ664.
Small Craft Advisory for PKZ035-036-641>644-661>663-671.
&&
$$
SHORT TERM...GFS
LONG TERM....NC
AVIATION...EAB
MARINE...GFS
HYDROLOGY...GFS
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