Graphical Hydro Meteorological Discussion

654
FXAK68 PAFC 121224
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
424 AM AKDT Sat Jul 12 2025

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through
3/Today through Monday evening)...

A weak shortwave continues to slide south through the southern
Copper River Basin this morning. Light rain persists along the
Chugach, across Valdez, and into Prince William Sound. Farther
west, increased instability is lending to scattered showers over
the southern Talkeetnas southwest across parts of the Anchorage
Bowl and western Kenai Peninsula. Both areas of rain and showers
are expected to taper off through Saturday morning.

The forecast remains on track through the weekend, with quiet
weather expected overall. The upper low in the NE Gulf will exit
to Canada while an Arctic ridge builds southward across the
mainland to Southcentral. The ridge will cut-off as it moves
overhead of Southcentral Saturday night, then connect up with a
building ridge over the NE Pacific and shift eastward Sunday
through Monday. Model guidance is coming into better agreement
with a weak shortwave rounding the base of the ridge and moving
over the Kenai Peninsula for late Saturday with a second,
stronger wave for late Sunday into Monday lifting north across
the western Gulf and into Cook Inlet as the arctic ridge slides
to the southeast.

Given the latest model guidance, the forecast for the weekend
looks the same, with mostly dry conditions and partly to mostly
sunny skies for most of Southcentral. There will be enough
instability for some afternoon/evening convection, but with weak
storm motion, these will be confined primarily to higher terrain.
There is also potential for a push of low clouds up Cook Inlet as
the ridge shifts eastward by Sunday morning, so that could lead
to more clouds and cooler temperatures for some communities on
Sunday.

Forecast confidence drops significantly for Monday. There is
overall agreement with the large scale pattern and flow, with the
ridge exiting eastward and Kodiak/Gulf of AK/Southcentral all
coming under the influence of multiple upstream troughs and deep
southerly flow. Guidance varies on the track and strength of
individual short-waves and therefore on potential for rain. At a
minimum, expect a trend toward cooler and cloudier conditions.
None of the features look particularly strong, so also expect a
chance of rain - but likely light intensity and accumulation.

-SEB/TM

&&


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

The forecast generally remains on track; the most notable
overnight update was to increase wind speeds and adjust the timing
of rain as a front sweeps eastward across the Bering Sea on
Sunday and Monday. Otherwise, much of the previous forecast
discussion stands, with a few minor edits:

Conditions across Southwest Alaska and the Bering Sea are fairly
quiet owing to a collection of weak weather systems affecting the
area. Weak ridging over the Alaska mainland and light offshore
flow will lead to fairly warm temperatures, with high
temperatures in the upper 60s and into the 70s for Southwest
Alaska. Warm temperatures and weak shortwaves rotating around the
ridge will continue to produce scattered to numerous showers
across much of the region through the weekend. Temperatures reach
their peak today with interior areas seeing highs exceed 70
degrees as ridging builds in overhead. This will also contribute
to thunderstorm potential, with isolated storms developing
generally along an axis from the Western Alaska Range over the
Kilbuck and Ahklun Mountains, which through the evening hours
should migrate off the high terrain with potential to move into
Aniak, Bethel, and there is even a chance to reach parts of the
Kuskokwim Delta coast, particularly near and south of the mouth of
the river.

Out west, a weak surface low brings light rain and low stratus to
the Bering Sea and Aleutians. The low dips south of the Aleutian
Chain today, spreading precipitation as far as the eastern
Aleutians and southern Alaska Peninsula. Otherwise, a col over the
eastern Bering Sea leads to stagnant conditions with stratus and
fog. The upper component of the low weakens and elongates, pushing
back north on Sunday. This combines with an incoming front off a
Kamchatka low that returns southerly winds to the western Bering
Sea. A subtle shift to onshore flow also beings on Sunday for
Southwest Alaska, heralding cooler and more stable conditions.
This will increase fog and stratus potential along the coast, and
thunderstorms retreat inland, being limited to the Lower Kuskokwim
Valley and Western Alaska Range for Sunday afternoon/evening. By
Monday, the bulk of the front reaches the central Bering Sea and
the Pribilof Islands, though winds remain below gale force. A
broad shortwave trough lifts across Southwest Alaska, promoting
more widespread wetter conditions with numerous rain showers.

&&

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

Low pressure in the northern Gulf of Alaska remains fairly
stationary through the end of next week though its exact placement
remains uncertain. The GFS places it off the coast of the Kenai
Peninsula with the Canadian and ECMWF both place it just east of
the Barren Islands. Therefore, confidence on the duration and
frequency of the waves of moisture and cloudy conditions each
model suggests into Southcentral is low. However, partly cloudy
skies are most likely in Southcentral away from the coast. High
pressure builds for the Copper Basin in the long range resulting
in a better chance of partly cloudy skies and dry conditions.

In the Bering, a low moves through the Northern Bering Sea during
most of the long range period. Additionally, high pressure
strengthens over the SW Mainland. Though timing and strength
differ with each model, consensus is that the front progresses
eastward toward the SW Mainland as the high builds over the
Mainland. Confidence remains low though in this solution because
of the non-model consensus. Widespread rain and cloudy skies will
accompany the front though regardless of its exact track.


&&


.AVIATION...

PANC...VFR conditions are expected to persist through the period.
Winds will generally be light and southerly through midday today,
then becoming westerly to southwesterly this afternoon. Showers
also look to develop this afternoon, but should remain mostly
confined to the mountains.

&&


$$

341
FXAK69 PAFG 112244
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
244 PM AKDT Fri Jul 11 2025

.SYNOPSIS...
A building area of high pressure over the region today through the
weekend will result in generally warmer and drier conditions for
most areas. This also means that fire weather concerns will be on
the increase as well through the weekend. Low pressure moving into
the Gulf of Alaska as well as the Bering will start to bring
somewhat cooler and unsettled conditions to much of the region
starting early next week.

&&

.KEY WEATHER MESSAGES...
Central and Eastern Interior...
- Mainly clear skies will help temperatures warm back to near
normal this afternoon and above normal for the weekend.

- Interior high temps well into the 70`s the next few days with
some spots reaching 80 by Sunday.

- Blustery north winds continue across the northern Interior through
Saturday.

- Slight chance of afternoon and evening thunderstorms across the
Upper Tanana Valley and Fortymile Country today and tomorrow.

West Coast and Western Interior...
- Warming and drying trend through the weekend with highs away
from the coast in the low to mid 70s by Friday and near 80 by
Sunday.

- Northwest winds increasing today with blustery conditions at
times through the weekend across Northwest Alaska.

- Chances for precipitation increasing Monday and continuing
through much of next week.

North Slope and Brooks Range..
- Temperatures moderate through the weekend and above normal
temperatures expected Sunday into early next week. Highs will be
in the 60s on the coast, up to around 80 near Umiat with 70s
across the Arctic Plain through at least the middle of next
week.

- West winds 20 to 25 mph persist across the eastern Arctic coast
today then shift to the east and weaken through the weekend.

- Cooler and wetter conditions return to the Brooks Range and
Arctic Slope Tuesday and Wednesday.

- Increasing southwest winds along the northwest Arctic coastline
become established early next week.

&&

.FORECAST ANALYSIS AND DISCUSSION...
An upper ridge will continue to build in over much of the state
over the next 24 to 48 hours as upper troughing stays in place
over the Bering Sea. This will continue to allow for mainly clear
skies across the northern half of Alaska with the exception of the
Arctic coast and portions of the North Slope where low stratus
and fog will remain in place through Saturday. As of early this
Friday afternoon satellite is indicating some cumulus buildups
over the Alaska Range and over portions of the Fortymile Country.
These areas will continue to have a chance at a few isolated
showers or thunderstorms this afternoon and evening and again
Saturday afternoon as some moisture wraps back into those areas as
a low departs eastward into western Canada.

Meanwhile most areas will see generally drier and noticeably
warmer conditions prevailing through the weekend with Sunday
being the warmest day of the stretch. Afterwards models continue
to be in general sync with a weak upper trough undercutting the
ridge and tracking from the southern Bering to the eastern Arctic
Coast Monday into Tuesday. This will temporarily bring a band of
moisture inland along the west coast and provide increasing rain
chances for the coastal and western Interior areas as well. In
addition some scattered rain and thunder could occur elsewhere
throughout the Interior and across the Brooks Range. Beyond this,
models remain at odds as to how much ridging returns to the
region, but the general idea is that warmer temps will return for
the balance of the week as scattered storm chances remain (see
extended forecast discussion for more details).

&&

.FIRE WEATHER...
High pressure continues to develop over the Interior. A warming and
drying trend will occur through this weekend. Temperatures will warm
into the 70s and lower 80s with Sunday being the hottest.
Humidities will fall into 20s and 30s. Fortunately light winds will
occur under this ridge. The exception will be the Upper Kobuk
Valleys where gusty westerly winds will occur Saturday. Those should
remain below red flag warning levels based on the latest guidance.
Low level instability will gradually increase the next several days.
This afternoon we will see isolated thunderstorms develop over the
mountains of the Fortymile Country and Alaska Range. Saturday
isolated storms will also be possible across southwest Alaska. With
the increasing instability isolated storms will also be possible
over the White Mountains and Brooks Range on Sunday.

&&

.HYDROLOGY...
There are no significant hydro concerns at this time as recent
rises along rivers and streams throughout the Interior have
peaked following localized heavier rainfall earlier this week.
These rivers and streams are forecast to slowly fall over the
next couple of days.

&&

.EXTENDED FORECAST DAYS 4-7...
Warmer and drier conditions falter Monday and Tuesday for the West
Coast and Western Interior, but mostly remain for the Eastern and
Central Interior. A 1000mb low moves into the high Arctic Monday and
helps undercut the ridge in the Interior bringing showery conditions
to the West Coast and parts of the Western Interior. The weakened
ridge will allow for additional convection across the Interior with
some showers and isolated thunderstorms expected, especially along
elevated areas. After Tuesday the ridge in the Interior builds back
and another low in the Bering tries to move into the pattern.
Confidence is low with this low as models have wildly different
solutions for it with a great deal of spread for the overall
pattern. The European ensemble favors the ridge building back strong
Wednesday which will keep that low from pushing into the Interior
allowing for more widespread warmer and drier conditions. The
Canadian ensemble now favors a stronger, more northerly solution for
that low which would set up a large area of southwest flow over the
state causing significant rainfall deep into the Interior. The GFS
ensemble has both the ridge and low being stronger which forces much
of that low further south keeping things warm in the north and east
and wetter in the southwest.

Confidence is quite low for which solution will ultimately verify,
but more solutions are favoring a stronger ridge for much of the
rest of the week which would keep most of the Interior warm and
mainly dry with some scattered convection possible.

Coastal Hazard Potential Days 3 and 4...None

&&

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

$$

Laney/Maier(Fire Weather)/Stokes(Extended)

045
FXAK67 PAJK 120642
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
1042 PM AKDT Fri Jul 11 2025

.UPDATE...Update to Long Term Discussion

&&

.SHORT TERM...Breezy conditions primarily for the evening portion
of today, breaks in clouds for the southern panhandle, and a
system moving in from the southwest describes the next 36 hours.
We are currently in a post frontal environment with plenty of dry,
warm air advection above 700 mb, sapping rain chances south of
Angoon. Areas on the west face of mountains such as Craig,
Klawock, and Hydaburg are expected to stay relatively socked in
from the westerly moist flow at the surface, upsloping on the
mountains. However, on the wayward side of the mountains, such as
Ketchikan, sunnier skies and less clouds are present.

Going into tomorrow, another developing system looks to move in
from the southwest, with a warm front moving up from the south. At
this time, we are expecting this warm front to move up as far as
Angoon, bringing more precipitation and winds. Not expecting
nearly as much precipitation compared to this last Thursday`s
system. While freezing levels look above 10,000 ft yet again, the
full depth of saturation extends only to around 600 mb. That in
combination with the bulk of the jet aloft passing to the south,
means that less moisture looks to push into the panhandle. While
still expecting some moderate rainfall in the southern panhandle,
no flooding is expected.

.LONG TERM.../Sunday through Friday/...

Key messages:
- Low continues precip for southern panhandle Sunday morning
- High pushes up from the south, dry but clouds linger next week

Details: Remaining precipitation over the southern and central
panhandle will diminish through the day, allowing potential for
blue skies to peek out in northernmost regions. Ridging moving
north through the gulf will push the low out of the panhandle and
set up for potential drier weather by Sunday afternoon. Clouds
are expected to linger through the beginning of next week, with
potential for skies to clear out in the southern panhandle for
Tuesday. Clearing skies, from south to north, along with warmer
temperatures aloft should allow for temperatures to rise near 70
degrees at the surface for a majority of the panhandle Tuesday and
Wednesday, with the highest chances for the southern panhandle and
communities in the inner channels. These temperatures could be
offset in many areas by the development of an afternoon sea
breeze. In the interior, Hyder could even see temperatures reach
near 80 degrees during this time.

A disorganized surface level low with associated upper level
troughing looks to bring precipitation back to the northern
panhandle Thursday, spreading south through Friday. Model spread
leaves much to be desired at this point, with many aspects of this
system varying from run to run including timing and associated
precipitation amounts. Stay tuned for further updates as we go
through the weekend.

&&

.AVIATION.../06z Saturday thru 06z Sunday/ Scattered showers are
lingering over the region Friday evening with quite apparent
mountain wave clouds visible with satellite imagery under the W-SW
flow. The showers are causing variable conditions changing from VFR
down to MVFR or even IFR CIGs at times, therefore extended tempos
are needed. After about 12z, expect to feel the influence of the
next low approaching the southern panhandle from the SW. This will
shift wind directions across the north and cause steady rain and
MVFR conditions across the south for most of Saturday. The
northern edge of the rain should lie just south of PAJN/PAGS, but
wouldn`t rule out some lower conditions there in the morning.

&&

.MARINE...

Outside: Westerly moderate to fresh breezes (20 knots) will give
way tonight to southeasterly winds as the next incoming system
moves up from the southwest. Interestingly enough, run to run
models have the low track shifting ever so slightly northward, to
between the tip of Baranof Island and Sitka. A somewhat uncommon
pattern for the panhandle, will result in strong breezes to near
gales for the entrance to Dixon and the western outer coast of
Prince of Wales Island. A tip jet is expected to develop out of
Cross Sound, enhancing winds from the north to 20-25 knots. This
system is expected to become stationary, blocked by the mountains,
before shifting southward as the jet aloft shifts southward.

Inside: A southerly push is currently working its way through Icy
Strait, Stephens Passage, and soon to be Lynn Canal through this
evening. For Icy Strait, gap flow is expected to bring winds up to
a fresh to strong breeze (20-25 kt) from the SW. With the westerly
low level CAA, expecting continued pressure rises, which will is
currently driving the southerly push that will move into Lynn
Canal shortly. With the incoming system moving in from the
southwest, expecting a shift to the NE in Frederick Sound,
northern Chatham Strait, and easterlies in Sumner Strait, all up
to a moderate to fresh breeze. Clarence is expected to increase to
at least a small craft as the warm front moves in from the south.
Near Point Couverden, not expecting any tip jet development, as
sunny skies in Canada is expected to cause lower pressure, thus
limiting pressure gradient driven flow in Lynn Canal.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Small Craft Advisory for PKZ012-036-641-642-661>663.

&&

$$

SHORT TERM...NC
LONG TERM....ZTK/STJ
AVIATION...Bezenek
MARINE...NC

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