Graphical Hydro Meteorological Discussion

682
FXAK68 PAFC 091336
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
536 AM AKDT Mon Jun 9 2025

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

A cold-core upper level low is moving into Southcentral Alaska
today. The first wave from this low is moving through the
Matanuska Valley and Susitna Valley early this morning bringing
areas of fairly heavy rain showers. There will be periods of rain
showers throughout SOuthcentral today as this low moves through
the area. The big uncertainty is whether there will be enough
instability for a thunderstorm or two to develop. The cold air
aloft in conjunction with this low is certainly a big factor in
favor of this possibility, however, it looks like surface
temperatures will be cool enough throughout the day to really
make it difficult to initiate convection. The big caveat is
whether there will be any sustained breaks in the could over the
Kenai Peninsula and Susitna Valley. this could happen as the low
passes over the area and westerly flow in the lee of the Alaska
and Aleutian Ranges allows enough cloud breaks, However, the
atmosphere is pretty saturated so it does not look likely to have
long enough breaks in the cloud cover today to really get the low
levels warm enough so backed off on the chance of thunderstorms
today, though it will be something to keep track of as the day
progresses.

By Tuesday, the low will move into the Gulf and then slowly
continue its southeasterly journey out of the area as an upper
level ridge moves into the region beginning Wednesday. This will
bring some partial clearing for Tuesday, but still enough moisture
for afternoon and evening showers along the mountains and in the
Copper River Basin. Wednesday will see areas around Cook Inlet
become mostly sunny and warm up to near or above normal
temperatures. The Copper Basin may still see lingering showers or
thunderstorms Tuesday or Wednesday.

&&


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

Isolated thunderstorm activity is possible along the foothills of
the Western Alaska Range and eastern portions of the lower
Kuskokwim Valley this afternoon. Otherwise, mostly partly cloudy
to mostly sunny and dry conditions are expected to continue
across much of Southwest Alaska.

Ridging over the eastern Bering Sea shifts eastward through today
promoting areas of low stratus and/or patchy fog. Low clouds will
spill over onto the Southwest Coast as the ridge pushes onshore
today. A front moved into the western Bering/Aleutians yesterday
evening, bringing widespread rain and small craft winds, as well
as a small corridor of gales over the Rat Islands and Andreanof
Islands. The front tracks eastward over the next couple of days,
bringing precipitation to the Eastern Aleutians and southern
Alaska Peninsula by Tuesday. As for mainland Southwest, the
Kuskokwim Delta Coast and Nunivak Island have the best chance to
see light rain on Tuesday as most of the moisture remains to the
north of west of Bristol Bay and the rest of mainland southwest.

&&


.LONG TERM FORECAST (Days 4 through 7: Thursday through
Sunday)...

Ridging high pressure from the North Pacific will extend across
much of the Gulf of Alaska and South Central portion of the State
through late Saturday. The ridge breaks down over the Gulf as an
an area of low pressure retrogrades westward from the Panhandle,
back over the Eastern Gulf late in the weekend. This will setup a
weak southerly wind pattern across western inland portion of the
State and allow for warmer inland temperatures and an increased
chance of convective activity across the inland regions. The GFS
and Canadian models are in fair agreement with this pattern with
the European being less dramatic with the westward progression of
the Gulf low.


A well developed upper-level low and its surface fronts, over the
Western Bering Sea and Western Aleutians, will slowly weaken and
recede northward towards the Chukchi Sea by early Saturday. A
series of upper-level shortwave troughs will move into and across
the Southern Bering and Central Aleutians through the end of the
forecast period. The Canadian and European models handle this well
with the GFS being the slight outlier.


-DD

&&


.AVIATION...

PANC...VFR conditions and vicinity showers will be common through
midday across Anchorage as an upper trough moves from interior
Alaska down into the western Gulf. Expect shower chances to
increase in the afternoon with MVFR conditions likely over the
latter half of the day. Winds will remain light through the TAF
period.

&&


$$

112
FXAK69 PAFG 092141
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
141 PM AKDT Mon Jun 9 2025

.SYNOPSIS...
Pattern change begins today with building pressure and rising
temperatures through the week. Interior highs reach the 70s
Wednesday and Thursday with good chances of hitting 80 in the
valleys this weekend. The North Slope sees highs rise to near 50
by Wednesday and to near 60 this weekend accelerating snowmelt and
breakup. Southerly winds and showers return to the West Coast
Tuesday and last through the end of the week.

&&

.KEY WEATHER MESSAGES...
Central and Eastern Interior...

-Temperatures warm through the end of the week with valley highs
in the upper 50s to low 60s Monday rising to near 70 Wednesday
and into the upper 70s to low 80s this weekend.

-Showers continue in the Yukon Flats and Eastern Brooks Range
through Monday. Isolated showers possible Tuesday afternoon.

-Isolated thunderstorms possible amongst scattered showers each
afternoon in the far southeastern Interior.

West Coast and Western Interior...

-Temperatures warm through the end of the week. Coastal highs in
the upper 40s to near 50 Monday increase to the low to mid 50s
Wednesday and to near 60 this weekend. Western Interior highs
near 60 today increase to the mid to upper 60s by Wednesday and
to near 70 this weekend.

-Rain showers return to the West Coast Monday night into Tuesday
and remain through the end of the week. The heaviest showers will
be along the southern Seward Peninsula and Chuckchi Sea Coast.

-Winds shift southerly late Monday and strengthen Tuesday.
Southerly winds through the Bering Strait up to 35 mph and 15 to
25 mph elsewhere. These will last through the end of the week.

North Slope and Brooks Range..

-Temperatures warm through the end of the week. Highs in the mid
to upper 30s Monday rise to the mid 40s Wednesday and to the low
50s this weekend. Southern location nearer the Brooks Range could
see highs near 60 this weekend.

-Snowmelt increases greatly this week as temperatures rise. Snow
levels reach around 5000 feet Wednesday. Breakup is very likely
to begin this week.

-South to southwesterly winds persist through the week. These will
strengthen to 15 to 25 mph late Tuesday and help keep low clouds
and fog offshore.

&&

.FORECAST ANALYSIS AND DISCUSSION...
A 545 dam upper level low over South Central Alaska continues to
move south into the Gulf of Alaska, reaching the Gulf early
Tuesday morning. Higher pressure builds into Northern Alaska as
the low moves south allowing a ridge over the Eastern Bering Sea
to move through the West Coast and set up over the Interior and
North Slope. Ridging continues to build through the week in the
Interior which supports a strong warming trend with Interior highs
reaching near 80F this weekend. Two additional lows move into the
Western Bering Sea Tuesday and Wednesday increasing southerly flow
through the Bering Strait and allowing for heavy rain showers
along the West Coast, particularly along south facing shores.

Models are in good agreement on the overall pattern through Friday
morning. This means that confidence is very high for the building
ridge and strong warming trend through the end of the week. After
Friday models begin to diverge in their solutions limiting
confidence. Ridging is still likely in the Interior, but details
around the ridge become very fuzzy. The low in the Bering will,
most likely, move southeast over the Alaska Peninsula early next
week and begin to push back against the ridge. Models completely
differ on how to handle the low in the Gulf of Alaska during this
period with the Canadian and GFS showing the low retrograde
towards the Alaska Peninsula, and the ECMWF showing the low moving
even further south. If the former then the low over the Alaska
Peninsula will grow stronger and be more likely to push out the
ridge. If the latter, then the ridge will more likely persist into
next week.

&&

.FIRE WEATHER...
Major pattern chance imminent as a ridge builds over the Interior
through the weekend. Temperatures rise with Interior highs in the
70s by mid-week and near 80 this weekend. Minimum RHs fall into
the 20s and 30s across most of the area Tuesday and remain low
through the remainder of the week. The exception being the West
Coast where southerly flow will bring heavy rain showers to
south facing shores and lighter rain showers to the rest of the
West Coast. Isolated thunderstorms possible each afternoon in the
Upper Tanana Valley and southern portions of the Fortymile
Country, but the weaker signals suggest that storms will be quite
isolated. Thursday shows a higher potential for thunderstorms
across more of the Eastern Interior, but still keeps storms east
of Fairbanks and south of Fort Yukon.

&&

.HYDROLOGY...
The only breakup concern remaining is the Sag River. Temperatures
return to normal Monday and increase rapidly through the end of
the week with temperatures reaching into the 50s in the Sag Basin
Wednesday and the mid 50s to near 60 this weekend. This will
massively increase snowmelt and should be enough to finally get
breakup started up there, and we`ll be monitoring conditions as
they evolve along with the Alaska-Pacific River Forecast Center.

&&

.EXTENDED FORECAST DAYS 4-7...
A major pattern shift starting in the short term continues into
the extended forecast period. A ridge builds over the Eastern
Interior and brings high temperatures to the Interior and North
Slope. A low in the Bering Sea will continue to support southerly
flow and showers along the West Coast into the weekend.

Coastal Hazard Potential Days 3 and 4...None

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...None.
PK...Small Craft Advisory for PKZ801.
Small Craft Advisory for PKZ802-810.
Small Craft Advisory for PKZ806-850.
Brisk Wind Advisory for PKZ807.
Small Craft Advisory for PKZ811-851-854-857.
Small Craft Advisory for PKZ812.
Small Craft Advisory for PKZ816-817.
Small Craft Advisory for PKZ853.
Brisk Wind Advisory for PKZ856.
Brisk Wind Advisory for PKZ858.
&&

$$

Stokes

667
FXAK67 PAJK 100554 AAA
AFDAJK

Southeast Alaska Forecast Discussion...UPDATED
National Weather Service Juneau AK
954 PM AKDT Mon Jun 9 2025

...New 06z Aviation Discussion and Short Term Update...

No major changes to the forecast this evening as ridging
continues to build in aloft with surface winds decreasing.
Adjusted inner channel winds to better match ongoing observations,
particularly Stephen`s Passage. Anticipate winds to continue to
decrease overnight, going calm and variable for much of the
panhandle. Guidance continues to hint potential fog development
for portions of the panhandle, although this is a low forecast
confidence with dew points dropping slightly through the evening
and dependent on if skies clear tonight.

&&

.SHORT TERM...
The previous system has moved north into southern Alaska
today, allowing for calm weather to begin the week. Winds and
precipitation continue to dissipate through the day as a high
pressure system moves into the southern gulf. A broad ridge is
building over the panhandle, giving many areas a break in the
rainy conditions and even potential to see some sun. Upper level
onshore flow keeps a chance for light showers in the forecast for
the northern and central panhandle, though accumulations remain
minimal. Temperatures are still below normal for this time of year
with highs in the mid 50s and lows in the mid 40s.

.LONG TERM...
Less active weather remains in the forecast for a majority of the
week with a broad area of ridging remaining over the panhandle.
There is still a chance of scattered showers for the northern
panhandle through this period due to 500 mb zonal onshore flow.
Winds will decrease and remain light until turning easterly with
the next system moving over the panhandle on Thursday.

The weak surface low with associated upper level easterly flow
will increase the chances for convective showers later in the
week, especially for the northern and inner portions of the
panhandle. QPF remains low for this system with minimal to no
accumulation expected. The potential for easterly thunderstorms is
being considered, though moisture levels look relatively dry with
normal surface temperatures. The EFI table currently shows
agreement for increased gusts on the western side of Canada. Most
models agree on low CAPE, slightly unstable lapse rates, and a
positive lifted index. Uncertainty still remains because the GFS
shows more likely of a chance for these variables to line up,
along with increased vorticity and an inversion.

After the system on Friday, there is potential for another dry
period through the weekend before the next system reaches the
panhandle Tuesday. A broad upper level low helps guide a
relatively weak surface low northeast through the gulf, with the
front looking to reach the outer coast by Tuesday morning. EC runs
have stretched and weakened the upper level low more so than
other model runs, which causes the surface low to fall apart and
give the panhandle another dry day. Either way, showers will most
likely follow. Temperatures are looking to increase slightly
through the week, with some areas seeing highs in the low 60s and
lows in the high 40s.

&&

.AVIATION.../through 06z Tuesday/...
Predominate VFR conditions across the panhandle this evening with
ceiling AoA 4000ft, outside of Yakutat which is seeing MVFR
flight conditions with reduced CIGS around 2000ft. Anticipating
ceilings to drop a bit tonight around 2500ft to 3500ft with flight
conditions MVFR to low- end VFR. Potential for isolated dense fog
tonight dropping flight conditions to IFR for a few hours near
12z with moisture trapped under the weak ridge, however, with dew
points drying out a bit this evening and broken to scattered
skies, low forecast confidence at this time. Winds should continue
to decrease through tonight, around 7kts or less, increasing
again to around 5 to 10kts through tomorrow, up to 15kts for
Skagway. For Tuesday, anticpating VFR conditions to prevail with
CIGS AoA 5000ft by 00z.

&&

.MARINE...
Outside Waters:
As a ridge builds in the gulf, winds diminish to 5 to 10 across
most of the outer coastal waters, barring the far southern outer
coastal waters which will see winds closer to 15 kt. Wave heights
of between 4-6 feet are expected. Still a general southwest swell.
These conditions continue until a weak low enters the Gulf on
Wednesday, increasing winds towards 15 kt across many of the outer
coastal waters by late Wednesday night.

Inner Channels:
Winds for most of the inner channels will be around 5 to 10 kts
or less through the next few days. The exceptions will by Lynn
Canal (which will see stronger southerly winds Monday night, and
could see some sea breeze winds Tuesday afternoon), and Clarence
Strait, where NW winds of up to 15 kt are expected at times
through the first half of the week. Otherwise, only other wind
concerns will be the potential for some additional sea breezes in
the afternoon hours in locations like Icy Strait.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...None.

&&

$$

SHORT TERM...ZTK/NM
LONG TERM....ZTK
AVIATION...NM
MARINE...GFS

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