027
FXAK69 PAFG 082340
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
340 PM AKDT Tue Sep 8 2026

.KEY MESSAGES...

Central and Eastern Interior...

- Scattered rain showers will continue across the Interior as a
  cold front begins to build in out of the west. Isolated
  thunderstorms will be also be possible in the Eastern Alaska
  Range northeast across the Middle/Upper Tanana Valley and
  Fortymile Country through this evening.

- Behind and along the cold front, winds will ramp up out of the
  west as drier conditions build in. Wind gusts for most will
  peak Wednesday with gusts up to around 30 to 40 mph. Wind
  Advisories remain in effect tonight into Wednesday.

- Temperatures will trend cooler today into Wednesday associated
  with the front, with highs in the 50s/60s and lows mostly in
  the 50s, with a warming trend expected Thursday into Friday
  with southerly flow increasing.

- A strong low will track northeast from the Western Bering Sea
  through Siberia towards the Chukchi Sea Wednesday into
  Thursday and Friday, ejecting a warm front into the Interior
  Thursday followed by atmospheric river moisture Friday into
  Saturday.

- This system will support widespread rain and breezy winds
  regionwide, with rainfall amounts through Saturday west of and
  including FNSB around 0.50 to 1.50 inches and along the
  Central Alcan Border near Eagle. Lighter totals are expected
  across the Yukon Flats and Upper Tanana Valley given
  downsloping flow.

West Coast and Western Interior...

- Rain showers will continue across Western Alaska today,
  culminating with a cold frontal passage tonight into Wednesday
  with wind gusts around 25 to 35 mph.

- A strong low will track northeast from the Western Bering Sea
  through Siberia towards the Chukchi Sea Wednesday into
  Thursday and Friday, ejecting a warm front into Western Alaska
  late Wednesday into Thursday followed by atmospheric river
  moisture Friday into Saturday.

- This system will bring widespread rain, gusty winds, and
  onshore flow, with high surf and minor coastal erosion
  expected.

- High Surf Advisories have been expanded to include all of the
  coastline from the Yukon Delta to Kivalina for water level
  rises around 2 to 4 feet above the normal highest high tide
  line. High Wind Warnings have also been issued for St.
  Lawrence Island and the Bering Strait for wind gusts up to 65
  mph.

- Coastal impacts will continue to be monitored, with the
  potential for upgrades for some zones from High Surf
  Advisories to Coastal Flood Advisories dependent on the latest
  forecast trends.

- Storm total rainfall amounts will be around 0.50 to 1.50
  inches regionwide, locally higher in the Southern Seward
  Peninsula, NW Arctic Coast, Western Brooks Range, and
  Kobuk/Noatak/Wulik River Valleys around 1.50 to 2.50 inches.

- Temperatures will hold steady this week with southwest flow,
  with highs in the 40s/50s to low 60s and lows mostly in the
  40s.

North Slope and Brooks Range...

- A front lifting northeast will bring isolated to scattered
  rain showers to the Brooks Range and NW Arctic Coast, with
  that front then tracking east Tuesday into Wednesday with more
  scattered to widespread rain chances with a rain/snow mix
  across higher elevations of the Brooks Range.

- A strong low will track northeast from the Western Bering Sea
  through Siberia towards the Chukchi Sea Wednesday into
  Thursday and Friday, ejecting a warm front into Western Alaska
  late Wednesday into Thursday followed by atmospheric river
  moisture Friday into Saturday.

- This system will bring widespread rain, gusty winds, and
  onshore flow to Western/NW Arctic Coast, where high surf and
  minor coastal erosion is expected.

- Storm total rainfall amounts are expected to be around 0.50 to
  1.50 inches regionwide, with higher totals in the Western
  Brooks Range around 1.50 to 2.50 inches.

- High Surf Advisories have been issued for the Western/NW
  Arctic Coasts from Point Hope to Wainwright for water level
  rises around 3 to 5 feet above the normal highest high tide
  line. High Wind Warnings have also been issued for Point Hope
  to Point Lay for wind gusts up to 65 mph.

- Temperatures will see warming trend through Friday, with highs
  climbing to the 40s/50s to low 60s and lows in the 30s/40s,
  colder across higher elevations of the Brooks Range.

&&

.SYNOPSIS...
This is the work PIL for AFD Synopsis.

&&

.SHORT TERM...Today through Friday.
Not much change has been made to the overall forecast. A quick
look at satellite imagery shows much of the state covered with
mid to low level clouds and scattered showers. This is
associated with a 544 decameter upper level low that has set up
over Bristol Bay. This continues to provide much of Northern
Alaska with southerly flow aloft, allowing for the continuous
influx of moisture and shortwaves. The southerly flow continues
to provide the Alaska Range passes with gusty southerly winds
and is expected to continue throughout Tuesday morning. The rest
of the day will consist of this upper level low progressing
eastward across the Alaska Peninsula, and into the northern
portion of the Gulf of Alaska. This will continue to provide
isolated showers across portions of Northern Alaska. As the
shortwave moves into the northern Gulf, 850mb and 925mb
temperatures are showing a slight cooling trend as cooler air
moves in from the NW. This will help to slightly amplify the
trough, setting up west to northwesterly flow across Northern
Alaska as the trough axis moves across the Alaska Panhandle.

Starting early Wednesday morning, this northwesterly setup will
allow for a shortwave to move E-SE from the Chukchi to the
southern portions of the Yukon Flats. Previous model runs were
showing a good amount of disagreement with the trajectory of how
far south the trough will be able to push as it shifts east.
The latest runs show that models are trending toward the ECMWF,
which was expected based on the discussion from the previous
morning. A weak cold front is expected to progress W to E across
as part of this trough. This will allow for isolated showers to
continue across the North Slope and most of the Central/Eastern
Interior. As the front moves across the state Tuesday night
into Wednesday, a 30-40kt westerly, low-level jet is expected to
form across much of the Interior. This will provide much of
this area with increased wind gusts through Thursday morning.
The strongest winds across the Interior are expected to be at
the higher elevations, along with any valleys that are not
sheltered by terrain to their west. A series of wind advisories
are in effect across the Interior through Wednesday night.

Meanwhile, a 980mb low will be moving NE from the Western
Bering into Siberia Wednesday night with an upper-level ridge
building up over the Bering Sea. This building ridge will set up
the potential for a 1040mb high to set up in the north Pacific
and play a major role for the remainder of the forecast period.
An associated warm front will extend to the SE from the low over
Siberia, moving NE across the West Coast Wednesday night into
Thursday. The low over Siberia and the high in the north Pacific
will set up a period for prolonged south to southwesterly flow
across the Bering Sea and West Coast. Integrated Vapor Transport
outputs from several models are showing the potential for this
system to tap into an atmospheric river stretching as far
southwest as Japan. This will provide much of the West Coast a
chance to see heavy rainfall through the end of the week, with
storm totals as high as 1.5" to 2" in some locations. With the
southwesterly flow, the most favorable positions for the
heaviest precipitation will be on the south side of higher
terrain. These areas include the southern Seward Peninsula and
areas south of the Western Brooks Range. The prolonged period of
strong, southwesterly winds will also provide a chance for
coastal concerns across the West Coast. More on this will be
discussed in the Coastal Hazard section.

By Thursday, the ridge from the Bering will continue to shift
east across the state as the low from Siberia shifts NE out of
Siberia and into the Chukchi. By this point, the strongest gusts
across the West Coast will shift through the Bering Strait and
the NW Arctic Coast. The strength of this ridge will play a role
as too how much precipitation will fall across the southern
portions of the Interior. The latest guidance is showing the
potential for a decent amount through the start of the weekend.

Main updates today on the day shift centered around upgrading
the High Wind Watches to High Wind Warnings for St. Lawrence
Island northeast through the Bering Strait to the NW Arctic
Coast, and including the Yukon Delta and Interior Norton Sound
to High Surf Advisories. Impacts remain on track, with the
continual monitoring of latest coastal conditions expected. Here
is where we could see the potential upgrades for some coastal
zones to Coastal Flood Advisories dependent on latest forecast
guidance. The wind forecast and storm track remains in good
agreement.

&&

.LONG TERM...Saturday through next Tuesday.
The extended period begins on Saturday with an arctic low
oriented over the Chukchi Sea, and a powerful sustained ridge
over Alaska. This arctic low is accompanied with an atmospheric
river, and will continue developing as it progresses east
through North Alaska throughout Saturday. As this system moves,
it will force the sustained ridge east out of Alaska. As this
pattern continuously shifts throughout Saturday, the pressure
gradient that was initially set up between these systems will
weaken, but remain elevated through Sunday.

Total rainfall amounts from this system vary depending on
location. The heaviest rainfall amounts are localized to areas
of higher terrain, specifically the western portion of the
Brooks Range, western Alaska Range, and the Kigluaik Mountains,
with possibilities of totals between 1.5" to 2.5". Along the
West Coast rainfall amounts will likely be more mild, ranging
between 0.5" to 1.2" in most areas. Within the Interior rainfall
totals will likely range between 0.5" to an 1" with locally
higher amounts possible throughout this upcoming weekend.

The arctic low will fully move out of Northern Alaska by Sunday
morning which allows a ridge to begin to situate itself over
the Bering Sea by Sunday afternoon. This ridge will then track
east over Alaska as a new low pressure system moves north into
the Bering Sea Monday morning. There is reasonable disagreement
between models on how these systems will orient themselves
coming to the beginning of the next week, and impacts will be
dependent on this orientation.

If the ECMWF ensemble is correct, there is a strong likelihood
for the low pressure system to move north through the Bering
Strait and possibly approach Alaska through the Norton Sound on
Tuesday. This pattern could bring moderate to heavy
precipitation and gusty winds for the West Coast, as well as
some potential hydrologic impacts. However, if the GFS ensemble
holds true, then the low will likely get wrapped up into another
systems flow and be directed away from Alaska. In this solution
impacts would remain minimal as the system trends away from our
area. This pattern will continue to be monitored, until the
track has more confidence between model solutions.

&&

.COASTAL HAZARD POTENTIAL...
A developing Siberian low will move northeast towards the
Chukchi Sea setting up southwesterly flow across the West Coast.
This low will bring gale force winds into Norton Sound and
Kotzebue Sound. With these strong winds and long fetch of the
winds we will see water rises across the West Coast. For much of
the coastline we could see rises of 2 to 5 feet with the
highest rises from Elim to Unalakleet. These 2 to 5 feet rises
across the West Coast has led us to issue High Surf Advisories
across the Coastline from Hooper Bay to Point Lay. While no
flooding is expected, localized beach erosion may occur.

With the strong southwesterly winds continuing for roughly 48
hours, there will be multiple high tide cycles that will be
elevated. Waters will begin to rise Wednesday and will peak
Thursday night for the communities along the Norton Sound and
the Y-K Delta Coastline. The higher waters are expected to
continue through Friday. For communities along Kotzebue Sound
and then the NW Arctic Coastline waters will rise early Thursday
morning and peak Friday morning. The higher waters for this
region will continue into Saturday.

&&

.FIRE WEATHER...
Relatively cool and wet weather continues today across most of
the Interior as a low over the Gulf shifts eastward, with rain
spreading across most of the area. Fire weather concerns remain
low in Western Alaska and the North Slope, with the
Central/Eastern Interior and especially the southeastern
Interior being the primary area of concern. With areas of
clearing and relatively dry weather still in place, portions of
the Upper Tanana Valley are in the low to mid 60s with RH values
in the 30s. Isolated thunderstorms will also be possible in the
vicinity of these areas ahead of rain chances tonight into
Wednesday. Highs in the Central and Eastern Interior today will
drop into the low to mid 50s most areas Wednesday as further
rain and clouds move in, with min RH values remaining well above
critical thresholds. Even the Upper Tanana Valley will see
chances for wetting rains during this time frame. By Thursday,
rain will diminish across the southeastern Interior, with some
brief warming and drying possible by Friday ahead of additional
rain this weekend.

&&

.HYDROLOGY...
A strong low will move into the Chukchi Sea late Wednesday
night and will be accompanied with an atmospheric river
extending to the tropics. This atmospheric river will help to
produce 72 hour rainfall totals of 0.5" to 2.5" for most of
Northern Alaska. The Upper Tanana Valley and Upper Yukon will be
the driest spots with only up to 0.15" of rainfall expected. On
the flip side the wettest areas will be the Southern Seward
Peninsula and the south slopes of the Western Brooks Range will
be the wettest.

In the Western Brooks Range and Northwestern Interior
particularly the Kobuk, Noatak, and Wulik a hydrologic outlook
has been issued. With the continued periods of heavy rainfall in
the region the smaller streams will be more vulnerable to see
bankfull conditions and rapid rises. No flooding in this region
is expected.

Across most of Northern Alaska the mainstem rivers are low and
this next round of moderate rainfall is not expected to create
any flooding hazards. However, on the smaller creeks and streams
could see rapid rises and/or bankfull conditions. Recreators
should be prepared for rapidly changing water conditions in the
smaller tributaries.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...High Surf Advisory from 10 PM Wednesday to 4 AM AKDT Saturday
     for AKZ801-802.
     High Wind Warning from 4 AM Thursday to 4 PM AKDT Friday for
     AKZ801.
     High Surf Advisory from 4 AM Wednesday to 4 AM AKDT Saturday
     for AKZ815>818.
     High Surf Advisory from 4 AM Wednesday to 10 PM AKDT Friday
     for AKZ820>822.
     High Wind Warning from 10 PM Wednesday to 4 PM AKDT Friday for
     AKZ820-821-827.
     High Surf Advisory from 10 PM this evening to 10 PM AKDT
     Friday for AKZ824-825.
     Wind Advisory from 10 PM this evening to 10 PM AKDT Wednesday
     for AKZ831>846.
MARINE...Small Craft Advisory from 4 AM to 4 PM AKDT Wednesday for
     PKZ801-810-850-853-855.
     Small Craft Advisory from 4 AM to 6 PM AKDT Wednesday for
     PKZ802-803.
     Small Craft Advisory until 10 PM AKDT this evening for PKZ803.
     Small Craft Advisory until 6 PM AKDT Wednesday for PKZ804.
     Small Craft Advisory from 10 PM this evening to 4 PM AKDT
     Wednesday for PKZ805>807.
     Small Craft Advisory until 7 PM AKDT this evening for PKZ808.
     Small Craft Advisory from 4 AM to 1 PM AKDT Wednesday for
     PKZ808.
     Small Craft Advisory until 4 PM AKDT Wednesday for PKZ809.
     Small Craft Advisory from 7 AM to 10 AM AKDT Wednesday for
     PKZ811.
     Small Craft Advisory from 10 AM to 4 PM AKDT Wednesday for
     PKZ812.
     Small Craft Advisory from 4 AM to 7 AM AKDT Wednesday for
     PKZ816.
     Small Craft Advisory from 1 PM to 4 PM AKDT Wednesday for
     PKZ816.
     Small Craft Advisory from 1 AM to 7 AM AKDT Wednesday for
     PKZ817.
     Small Craft Advisory from 1 PM to 6 PM AKDT Wednesday for
     PKZ817-851.
     Small Craft Advisory until 4 PM AKDT Wednesday for PKZ852.
     Small Craft Advisory from 10 PM this evening to 10 AM AKDT
     Wednesday for PKZ854.
     Small Craft Advisory until 10 PM AKDT this evening for PKZ855.
     Small Craft Advisory from 1 AM to 4 PM AKDT Wednesday for
     PKZ856.
&&

$$

KEY MESSAGES...MacKay
SYNOPSIS.......MacKay
SHORT TERM.....Twombly/MacKay
LONG TERM......Donner
COASTAL........Dennis
FIRE WEATHER...DS
HYDROLOGY......Dennis