Graphical Hydro Meteorological Discussion

603
FXAK68 PAFC 260012
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
412 PM AKDT Tue Mar 25 2025


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

A stationary low off the coast of Kodiak Island coupled with a
weaker low near Yakutat continues to bring moisture to the Kenai
Peninsula and Kodiak Island through Thursday. This evening, a wave
of steady precipitation will push into the Kenai Peninsula with a
separate one Wednesday afternoon/evening. QPF amounts in each
wave will be light and heaviest north of Seward in the Eastern
Kenai mountains. Separate, smaller waves of moisture move through
southern Kenai Peninsula and the Island of Kodiak this evening
into tomorrow afternoon. Again, QPF amounts will be light in
these waves too. As this stationary low dissipates, northwesterly
winds through the Barren Islands are expected through most of
Thursday resulting in gale force winds. Dry conditions will
continue through Thursday elsewhere in Southcentral and Prince
William Sound.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days
1 through 3 - Tonight through Friday)...

Between high pressure in the central/eastern Bering Sea and a
broad area of low pressure in the Gulf of Alaska, cold northerly
flow continues to stream across the eastern Bering Sea and
Southwest Alaska this afternoon. With the exit of a strong upper-
level low into the North Pacific last night, gap winds across the
Alaska Peninsula have come down somewhat, but winds below gale
force will continue to filter south through Wednesday night.
Additionally, a field of stratocumulus will continue to wring out
moisture in the form of light upslope snow showers along the
peninsula south of Port Heiden. Weak shortwaves lifting up from
the Gulf of Alaska brings a bit of warmer air and moisture which
may allow some light snow showers to impinge on the Lake Iliamna
area and reach as far west as even King Salmon tonight into
tomorrow. Otherwise, expect dry and mostly clear conditions
across Southwest Alaska through the end of the week.

Out west, a front pushing through the central Aleutians this
afternoon reaches the Pribilof Islands and eastern Aleutians
tonight. For the Pribilofs, an inch of snow is expected to fall,
with rain further south along the Aleutians. The front quickly
falls apart through the morning hours on Wednesday. Wednesday
night into Thursday, a large area of high pressure builds across
the central and western Bering Sea, which an upper-level low
rides over top and dives south across the eastern Bering. The low
brings reinforcing cold air, increasing gap winds back to gale
force across the Alaska Peninsula for Thursday and Friday.

&&


.LONG TERM FORECAST (Days 4 through 7: Saturday to Tuesday)...

An upper level trough over Central Alaska weakens and slips into
Western Canada through the forecast period. A closed upper low in
the Eastern North Pacific weakens and exits over Queen Victoria
Island by Tuesday. The main axis of an upper level ridge
stretching from the North Pacific into the Arctic begins to
reorient over the Aleutians into the Interior and continues South
into the North Pacific for Tuesday. Forecast guidance with a well
clustered composite of GFS / ECMWF and Canadian models maintains
good overall continuity through the period.

A well developed closed surface low in the Eastern North Pacific
sweeps a couple of troughs across Southcentral Alaska through the
weekend as far South as Kodiak Island. Some rain showers may occur
mostly along the coastal areas. The last of gusty surface winds
over the Eastern Aleutians and Alaska Peninsula departs by Midday
Sunday. Highest gusts will come through channeled terrain into
bays and passes. A second area of gusty winds moves over the
Western Bering through early Sunday. A developing low and front in
the North Pacific brings gusty winds over the Western Aleutians
and Bering Monday and Tuesday. A second developing low in the
Arctic brings increasing winds to the Western Alaskan coasts
Monday and Tuesday.

- Kutz

&&

.AVIATION...

PANC...VFR conditions with light northerly winds continue through
Wednesday. An isolated shower is possible later this afternoon and
again Wednesday morning.

&&


$$

661
FXAK69 PAFG 252102
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
102 PM AKDT Tue Mar 25 2025

.SYNOPSIS...
The overall pattern is remaining consistent but we are seeing the
arctic front moving east tomorrow which will bring a slightly
greater risk for light snow in Fairbanks Wednesday evening into
Thursday. Otherwise, stratus and patchy dense fog persists along
the Eastern Arctic Coast through tomorrow. Flurries persist along
the West Coast but it will be drying out as ridging moves in
tomorrow.

&&

.KEY WEATHER MESSAGES...
Central and Eastern Interior...
- Warm this afternoon then a cooling trend through this weekend.

- Light snow in the Central Interior Wednesday evening through
Thursday with around an inch or less of snow in Fairbanks,
potentially 1 to 2 inches in the terrain around Fairbanks.

West Coast and Western Interior...
- Other than a few flurries, most of the area remains dry through
Friday.

- Temperatures will be on a warming trend to near seasonal norms
by the end of the week.

North Slope and Brooks Range..
- East flow tries to turn northeast on Thursday. Stratus and fog
remains predominant along the coast with nighttime fog in the
flats and Brooks Range valleys.

- Seasonal temperatures remain persistent through the end of the
week.

&&

.FORECAST ANALYSIS AND DISCUSSION...
A trough axis extends from Point Hope to the Gulf of Alaska with
the center at 530 decameters just north of Point Hope. Narrow
ridging exists to the west of this trough and extends from the N
Pacific to northeast Siberia. Troughing sits to the west of that
as well. A ridge axis extends from north of Utqiagvik to SE AK.
Broad troughing persists in the Gulf of Alaska. Troughing persists
over the Canadian Archipelago.

&&

.EXTENDED FORECAST DAYS 4-7...
On Saturday we will have a strong ridge at around 575 decameters in
the Northern Pacific/Southern Bering. A low will developing on the
north side in Siberia and move into the Arctic Sunday into Monday.
From here, models differ in the outcome. There have been trends
with this first round towards a high wind and moderate snow event
in the NW Arctic and Chukchi Sea Coast. Warm air will accompany
the first front and bring mixed precipitation chances along the
West Coast with the Chukchi Sea Coast not excluded yet.

In the Interior, there are vast differences with this front and
how it evolves. The EC AI model has been very consistent for the
last few days showing several inches of snow Sunday night into
Monday for much of the Interior. Other models such as the ECMWF,
GFS and Canadian have been consistent in showing a none-event, or
less than a few inches.

The battle in the models is because some want to have the front
barrel through the amplified high over the mainland, while others
get pushed up and over the ridge. This low is tapping into plenty
of cold air, so it my be enough to suppress the ridge, which
would bring more snow to the Interior. It is also equally possible
for the ridge to be strong enough to prevent moderate to heavy
snow. What is more certain is snow and blowing snow along the
Chukchi Sea Coast late this weekend into early next week.

Nonetheless, a second low will try to develop in Eastern Siberia
around Tuesday of next week. This could bring another chance for
widespread snow in the Interior. Details on this most likely be
determined when we have higher confidence on what the first front
is going to do.

Coastal Hazard Potential Days 3 and 4...None

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...None.
PK...Brisk Wind Advisory for PKZ815.
Brisk Wind Advisory for PKZ851.
Brisk Wind Advisory for PKZ861.
&&

$$

Bianco

841
FXAK67 PAJK 252207
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
207 PM AKDT Tue Mar 25 2025

.SHORT TERM...A weak low continues to move through the Gulf this afternoon
bringing rain showers to the panhandle with clearing farther south.
These showers will continue to move north through this evening while
the coverage across the south continues to decrease. Winds are
expected to become light as this system starts to move out of the
area. While farther to the south, a new low is expected to move
northward and be near the area. This low is expected to stay south
of the area but some showers may work northward into the Southern
Panhandle. Any showers that do make it into the area will be light.
The bigger concern though will be the development of outflow winds
across the North and Central Panhandle. Currently the strongest
winds look to be for the Lynn Canal as well as Downtown Juneau.
Downtown Juneau is expected to see wind gusts between 40-50 mph.
Gusts to 60mph are possible but confidence remains lower on this
potential. For the southern Panhandle, some downslope winds are
likely which will aid in warming up daytime highs across the area.
It would not be unreasonable to see some places get close to or
reach 60F for a high temperature tomorrow.

.LONG TERM.../into the weekend/...

Key messages:
-Outflow pattern continues in the midrange forecast with 20 to 30 kt
winds, gusts to 40 to 45 kts, in N-S oriented inner channels.
-Daily temps will have big swings with colder-than-normal morning
lows and warmer-than-normal afternoon highs.
-Lingering chances of precip for mainly the southern panhandle until
Saturday, that`s when the PoPs spread to the Icy Strait area.

Details:

Broad area of low pressure off the coast of the Pacific Northwest
will move northward toward the panhandle. At the same time, a high
pressure system in the Arctic Ocean is expected to build and extend
down into northern Canada. This will cause the N-S pressure gradient
to tighten, influencing strong outflow winds through the northern
channels. Lynn Canal will see northerly winds upwards of 30 to 35
knots with 20 to 30 knots lasting through Friday. Out of Taku Inlet
will see upwards of 20 to 25 knots. Farther south, lighter winds of
15 to 25 knots.

Afternoon temperatures will warm up this week with highs in the low
to mid 50s in the southern panhandle and temps well into the 40s
elsewhere. With clearer skies in the forecast, we will most likely
see cooler temperatures overnight with lows in the 20s to low 30s
for the central and northern panhandle and mid to upper 30s in the
south.

The front associated with the low mentioned earlier is expected to
bring precipitation to mainly the southern panhandle, south of Sitka
and Angoon. And what rain does fall will be light. On Saturday, the
precip may get pushed as far north as Icy Strait, but low confidence
on that.

As we head into the weekend, ensembles continue to keep the weather
active with a low in the Gulf of Alaska giving way to a low moving
up from the Northern Pacific. Right now, nothing stands out as being
problematic but guidance will still need to be watched in case this
changes going forward.

&&

.AVIATION...After a day of localized for and showers another weak
disturbance will bring another round of showers and it pushes N
through Tue evening. Clearing over the S tonight combined with light
BL winds will allow fog to develop overnight. Clearing spreads N
overnight with chances for fog around sunrise Wed. Northerly outflow
winds increasing turbulence and limited areas of LLWS into
Thursday.

&&

.MARINE...Most places continue to see gentle to moderate breezes across the
area while Fresh breezes have been reported along the Outer Coast.
Winds are and seas are expected to diminish this evening as the low
in the Gulf continues to move out of the area. This break will be
short though as a low approaching the Dixon Entrance will amplify
outflow conditions across the Panhandle. Winds are expected to
increase to strong breezes and near gales for areas favored by
outflow winds. The exception to this is Lynn Canal which is
currently expected to increase to gales during the overnight
Wednesday into Thursday morning. As we head into the end of the
week, outflow conditions are expected to continue across the area.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...High Wind Watch from Wednesday afternoon through Thursday
afternoon for AKZ325.
MARINE...Small Craft Advisory for PKZ033-642>644-661>664-671-672.

&&

$$

SHORT TERM...SF
LONG TERM....GJS
AVIATION...PRB
MARINE...SF
HYDROLOGY...99

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