506
FXAK68 PAFC 130103
AFDAFC
Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
503 PM AKDT Sat Jul 12 2025
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through
3/Today through Tuesday evening)...
Currently, there is a large upper high over Central Alaska. This
high is allowing for calm winds and clearer conditions across
Southcentral. However, there are some weak shortwaves moving
through the region. Showers and thunderstorms are possible in the
Talkeetna Mountains and the higher elevations of the Copper River
Basin with these waves. The Susitna Valley could see some storms
moves in from the Talkeetna Mountains due to easterly storm
motion. Sunday is almost the same story as today (Saturday). The
high will slowly track eastward, but will still influence the
region in the form of light winds and lower rain chances. There
will still be instability present in the Talkeetna Mountains and
the Copper River Basin, so chances for showers and thunderstorms
remain.
A pattern shift occurs on Monday. The upper high moves east into
Canada while a more troughy pattern moves into Southcentral. A
front pushes in from the south, allowing for widespread light
rainfall across the interior of Southcentral. Some blocking will
occur in the Susitna Valley, but the Anchorage, and Matanuska
Valley should see rainfall lasting through Tuesday morning. As
with everything, there is uncertainty in how this situation will
unfold. Some guidance has the front taking a more eastward track,
leaving the Anchorage and Mat-Su Valley regions drier and giving
the Prince William Sound region the brunt of the rainfall. Other
guidance has the core of rainfall impacting Anchorage and Palmer.
The real solution will likely fall somewhere in the middle. Winds
will pick up to an extent in the gap regions, but will remain on
the weaker side with this shortwave. Temperatures will cool down
to the upper 50s and low 60s thanks to the increased cloud cover
and rainfall. Afterwards, weaker shortwaves will pass through from
the west, keeping rain chances elevated in the higher elevations.
Looking ahead to Wednesday shows that model agreement falls off
the cliff as a low in the north Pacific tracks eastward. Most
guidance has a different scenario with some tracking it into the
Gulf of Alaska while others have it take a more northerly track.
The only thing that can be deciphered is that some kind of a front
will move into Southcentral.
-JAR
&&
.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS
(Days 1 through 3: Tonight through Tuesday)...
Southwest Alaska and the Bering Sea remain fairly quiet under a
weak flow regime. Weak ridging over the Alaska mainland continues
to build in today over Southwest Alaska, leading to high
temperatures in 70s for most of interior Southwest Alaska. Weak
shortwaves rotating around the ridge have combined with these warm
temperatures to produce scattered to numerous showers along an
axis from the Western Alaska Range over the Kilbuck and Ahklun
Mountains. Though none of have been observed yet, embedded within
these showers is the potential for some isolated thunderstorms
this evening. Showers are forecast to move off the high terrain
into the Kuskokwim Delta, bringing thunderstorm potential with
them. Showers, and any thunderstorms along with them, diminish
tonight with the loss of surface heating.
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 tonight, 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.
Light offshore flow for Southwest Alaska shifts onshore and
intensifies as surface high pressure builds to the east over the
Gulf of Alaska beginning tonight. This will bring in cooler and
more stable conditions, increasing fog and stratus potential along
the coast. Additionally, thunderstorms retreat inland for Sunday
afternoon/evening, being limited to the Lower Kuskokwim Valley
and Western Alaska Range.
By Monday, the bulk of the front pushing into the Bering reaches
the Pribilof Islands, though winds remain below gale force. A
broad shortwave trough lifts across Southwest Alaska, which will
continue to promote showers each afternoon and evening. For the
beginning of the week, expect high temperatures to cap out around
60 degrees for much of Southwest Alaska. On Tuesday, in addition
to the low out west, a second low lifts up around the ridge in the
Gulf/Northeast Pacific, bringing steady rainfall to the Alaska
Peninsula.
&&
.LONG TERM FORECAST (Days 4 through 7: Wednesday through
Saturday)...
The longterm forecast begins on Wednesday with a low in the
northwestern Gulf of Alaska and another low in the western Bering
Sea. Models are still struggling with the placement and evolution
of the low in the Gulf of Alaska. The GFS quickly moves the low
to the northeast into Canada by Thursday morning, the Canadian
shows the low tracking to the northwest and being absorbed into
the aforementioned Bering low, and the ECMWF has the Gulf low
moving due east to the Alaska Panhandle by Friday morning.
Therefore, confidence on precipitation and sky conditions is
still low. Towards the end of the longterm, high pressure builds
across the Copper River Basin and should promote a better chance
for less clouds and drier conditions.
In the Bering Sea, the low pressure system generally remains over
the Bering during most of the longterm while high pressure
strengthens over the AK Mainland. The main uncertainty with the
Bering low is in regards to how it interacts with surrounding
shortwaves/lows and the speed of its surface front. The GFS
solution would push the front quickly across SW AK and portions of
Southcentral (with the bulk of precipitation across SW on Saturday
morning), whereas the Canadian front is slower (with the bulk of
precipitation across SW on Sunday morning). Nonetheless, expect an
active pattern out west during the long term period.
&&
.AVIATION...
PANC...Ceilings expected to remain primarily VFR between 5-8 kft through
this evening with the potential for scattered showers mainly along
the Chugach Mountains. High pressure will build into the region
tonight with winds remaining light. This could set the stage for
low marine stratus to begin to work up the Cook Inlet towards the
terminal by Sunday morning. Confidence is stronger for low clouds
for the southern end of Cook Inlet, but less so for the low
clouds to work as far north as the PANC terminal Sunday morning.
&&
$$
416
FXAK69 PAFG 122332
AFDAFG
Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
332 PM AKDT Sat Jul 12 2025
.SYNOPSIS...
Upper ridging will continue through the weekend resulting in a
continuation of dry and warm conditions. Fire weather concerns
will increase over the weekend while areas of smoke and haze
return to many locations as well. Sunday marks the warmest day of
the weekend but we will also see our next system begin to push
onto the west coast with increasing rain chances by Sunday
afternoon. While wet weather will continue across the west, a few
showers and even some thunderstorms can be expected early next
week over the interior as this system continues to move across the
region.
&&
.KEY WEATHER MESSAGES...
Central and Eastern Interior...
- Areas of smoke and haze move back into the interior today and
tonight as the flow pattern shifts out of the northwest.
- Interior high temps well into the 70`s today and tomorrow with
some locations reaching 80 by Sunday.
- Winds remain generally light before shifting to the southwest
and increasing a bit Sunday night into Monday. Increasing gap
winds will occur through the Alaska Range Monday as well.
- Slight chance of afternoon and evening thunderstorms across the
Upper Tanana Valley and Fortymile Country today and tomorrow.
- Better rain chances for much of the interior Monday and Tuesday
with a potential lull in the action by midweek.
West Coast and Western Interior...
- Warming and dry today with highs away from the coast in the
upper 70`s to near 80 by Sunday.
- Increasing southwest flow beginning Sunday with stronger winds
expected to develop through the Bering Strait.
- Chances for precipitation increasing Sunday afternoon and
evening with the potential for additional wet weather through
much of the week ahead.
North Slope and Brooks Range..
- Above normal temperatures expected through the weekend and into
early next week. Highs will be in the 60s on the coast with 70s
across the Arctic Plain through at least the middle of next
week.
- Lighter winds through the weekend. Southwest winds increasing
along the Northwest Arctic Coast Monday and Tuesday.
- Cooler and wetter conditions return to the Brooks Range and
Arctic Slope Tuesday and Wednesday.
&&
.FORECAST ANALYSIS AND DISCUSSION...
Ridging aloft over northern Alaska continues to push southwards
across the region this afternoon and evening and should be
centered over the interior by Sunday afternoon. While some
convective activity will again develop near the Alaska Rang this
afternoon, that activity may be temporarily suppressed Sunday. As
a result the region will continue to experience warm and mainly
dry conditions through the weekend. However as the ridge descends
on the area, smoke from the ongoing fires across the northwest
interior will continue to infiltrate the rest of the interior
resulting in poor air quality to wrap up the weekend (and
depending on smoke thickness, high temps may be a little lower
than predicted as well).
Beyond the weekend we will likely see a short period of unsettled
weather as a trough that develops over the Bering Sunday manages
to push east into the interior. Precipitation and convection
should actually kick off Sunday afternoon and evening over the KY
delta and parts of the southwest interior as the flow becomes
southwesterly ahead of the trough. Then Monday as the trough
pushes into western Alaska, a piece of shortwave energy is
expected to track into the central Interior which will not only
increase coverage of showers and storms, it will also result in a
gap wind situation through the Alaska Range passes.
Temps will come back down a few degrees Monday and Tuesday as the
main trough aloft passes through. Afterwards things become a
little less clear as models handle the rebuilding upper ridge
differently. (See extended discussion for more on what may happen
later next week).
&&
.FIRE WEATHER...
High pressure continues to evolve across the interior and into
the north which will bring warming and drying to much of the
region. We fully anticipate temperatures to reach the upper
70s/low 80s and RH diminishing to below 30 percent for most areas;
with Sunday being the hottest and driest day for much of the
interior. By-and- large light winds should be largely prevalent
after the westerly winds diminish Saturday across the Kobuk
Valley, with much wetter southwest flow in place across the west
into the week starting late Sunday. The boundary layer will favor
instability over the next few days, with thunderstorm development
anticipated across the southwest Saturday into Sunday, with
thunderstorms development likely across the White Mountains and
Yukon Sunday into Monday.
&&
.HYDROLOGY...
No impactful hydrologic concerns are expected over the next
several days.
&&
.EXTENDED FORECAST DAYS 4-7...
Models continue to agree on the early portions of the extended
period as some showery and unsettled weather is expected through
at least Tuesday with a weak trough undercutting the dominant
ridge. However differences continue to be magnified for the later
stages of the period, primarily with respect to the location and
strength of the upper ridge. At this time we will still favor a
general model blend with a forecast for mild conditions with a
week upper ridge over the area and a weakening low over the Gulf
helping pull some moisture in under the ridge. This should allow
for at least some isolated shower and thunderstorm potential,
especially near and over areas of higher terrain.
Coastal Hazard Potential Days 3 and 4...None
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
AK...None.
PK...Small Craft Advisory for PKZ811-857.
Small Craft Advisory for PKZ856-858.
&&
$$
Laney/Park(Fire Weather)
995
FXAK67 PAJK 130537
AFDAJK
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
937 PM AKDT Sat Jul 12 2025
.UPDATE...06z Aviation Discussion
&&
.SHORT TERM...Not much change to the overall package, just
provided further confidence in ideas already present in the
forecast. Looking on satellite, the incoming system from the
southwest is just off the coast of Baranof Island, with inner
channels winds shifting NE in the northern half as expected.
Still not expecting large amounts of QPF with this system as the
depth of moisture is relatively small. Expect for rainfall to
mostly fall apart by this evening, with some light on shore flow
keeping precipitation chances in the forecast for the inner
channels due to low level moisture and orographic lift.
For tomorrow, reduced sky and PoPs down to mostly sunny and zero
chance of precipitation. With stronger ridging aloft coming from
the north and dry air advecting with it, good chances for
widespread clearing skies and surface ridging. Therefore, expect
sea breezes and warmer temperatures in the mid 60s tomorrow.
.LONG TERM.../Monday through Saturday/...
Key messages:
- Dry and partly cloudy conditions through the week
- Potential for rain to return Thursday and Friday
- Warming temperatures mid week
Details: Ridging moving north through the gulf will push the
previous low out of the panhandle and set up for drier weather
Monday. Clouds are expected to linger through the week, though the
potential for skies to clear out keeps growing every day. The
panhandle is expected to see partly cloudy conditions for much of
the week, though periods of more or less clearing are possible
throughout the day. Typically after there has been sufficient
surface heating a marine boundary layer may develop, bringing
clouds back to the northern panhandle. The southern panhandle will
continue to get more and more clear through the week, with
outflow winds picking up to moderate to fresh breezes coming out
of Clarence Strait. Clearing skies and 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. The GFS depicts a more organized system
that will send a stronger frontal band over the northern panhandle
with lots of precipitation, while most other models stay
relatively dry and calm Thursday. Friday`s condition remains
dependent on this track; if the system reaches the panhandle
Thursday morning that could mean Friday would be more dry, vs if
Thursday is clear Friday could receive the precip instead. Stay
tuned for further updates as we go through the weekend.
&&
.AVIATION.../Until 6z Monday/...
The remains of the weather system pushing though the southern
panhandle with northern edge of the precipitation line has pushed
to Sitka, where the line of precipitation is expected to fall
apart through this evening. South of the line, westerly onshore
moist flow will keep low ceilings between IFR and LIFR for much of
the night. Areas on the windward side of mountains facing the west
are particularly prone to poor CIGs. Similarly, lighter winds and
recent rainfall has made visibilities particularly variable
between 2-4 NM. Not expecting much improvement for conditions
south of Sitka.
Sitka is by far the most uncertain TAF site, as it sits directly
on the boundary line between dry and moist air. Velocity radar
returns show the winds aloft shifting southerly slightly, which is
currently bringing down VIS from rain. However, as it moves SEerly
with the low feature falling apart and dipping south, mountains
look to block some precipitation.
Otherwise, look for all sites to improve drastically tomorrow,
from north to south. Dry air from the north looks to sap away any
residual moisture aloft, clearing skies and returning the
panhandle to what is left of its summer. Expect sea breezes to
develop with Skagway expected to increase to 15 knots by midday.
&&
.MARINE...
Outside: As the incoming system hits the panhandle and weakens,
expect moderate to fresh northerly breezes along Baranof Island
and the NE Gulf coast. Special mention to Cross Sound, as a tip
jet developing will provide the highest magnitude wind speeds for
the northern half of the coastline in our AOR. In the southern
panhandle, there is the possibility of a short lived gale at the
entrance to Clarence Strait due to some terrain influences
(barrier jet), but not expecting anything as drastic, with a swift
change to westerly fresh breezes as the cold front pushes
eastward into the panhandle.
Inside: Lynn Canal has been stubborn today to become light as a
result of light troughing in the Yukon, but the gradient is
expected to relax in the coming hours. Otherwise, southern
Stephens Passage, Icy Strait, and Chatham Strait have all shift
north to northeast and have begun to increase, reacting to the
incoming low pressure off the coast of Baranof Island. Expect
speeds to increase to around a moderate breeze before relaxing
overnight. In Clarence and Sumner Strait, fresh to strong breezes
are expected to pick up shortly in response to the warm front
extending out from the low pressure. Looking towards Sunday,
expecting comparatively warmer temperatures and sea breezes to
develop. This means that Icy Strait, Point Couverden, Point
Craven, and Lynn Canal are expected to increase up to 15-20 knots.
A marine layer could develop tomorrow evening, causing changes in
wind speed in Icy Strait and visibility impacts to the outer
coast and entrances to the inner waters; however confidence is low
at this time.
&&
.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Small Craft Advisory for PKZ036.
&&
$$
SHORT TERM...NC
LONG TERM....ZTK
AVIATION...NC
MARINE...NC
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