539
FXAK69 PAFG 041342
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
542 AM AKDT Fri Sep 4 2026

.SYNOPSIS...
The active weather pattern continues unabated, with periods of rain
expected for most of the Interior through the foreseeable
future. An atmospheric river and its associated systems will
move through Friday and Saturday, bringing with them periods of
moderate to heavy rain, with some river rises expected, especially
along smaller streams in the interior. Although overall daily
rainfall totals diminish in the immediate wake of the
atmospheric river, a broad area of troughing will set up from
Sunday into early next week and send additional systems into the
area. A stronger system will move up from the Kuskokwim Delta
area on Tuesday. The one positive aspect of the rain will be
warming temperatures, as repeated rounds of SW flow help push
back the cooler arctic airmass that had previously set up over
the Interior.

&&

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

- Rainfall is expected to be moderate to heavy at times Friday
and again Friday night into Saturday as an Atmospheric River
associated with a low in the Bering continues to supply deep
moisture to the Western and Central Interior.

- Total rainfall of 1.00 to as much as 2.50 inches of rain will
be possible over the course of the next few days, with
isolated areas at elevation potentially seeing 3.00+; this
represents annual return intervals of up to 10 or even 25
years for some locations.

- Local main stem rivers will see significant rises, but should
be able to handle the expected excessive rainfall. However
smaller streams and rivers that feed the main stem rivers
could experience minor flooding.

- Despite the deep moisture push, portions of the Upper Tanana
Valley and Fortymile region will remain mainly dry, barring a
few showers.

- Warmer conditions are expected in the days to come, especially
in areas where the rain is less intense.

West Coast and Western Interior...

- Rainfall coverage diminishes along the West Coast for Friday,
returning Friday night as another wave arrives. However, parts
of the Western interior will continue to see periods of
moderate rainfall Friday through Saturday.

- S/SW winds along the Yukon Delta coast and into the Norton
Sound will diminish somewhat in speeds to between 20 and 30
mph. However due to a long fetch of these southerly winds
through the Bering, water levels are expected to continue to
rise, especially for the Norton Sound where High Surf
Advisories remain in effect through Saturday morning.

- Water levels could potentially reach 2 to 4 feet above the
normal high tide, with highest levels expected around Golovin
and Elim Friday morning. A secondary water level rise is
expected Saturday morning around the time of high tide.

North Slope and Brooks Range...

- Winter`s chill will weakens through Saturday as the warm front
pushes north, although a low north of the Arctic coastline
will continues to bring bands of mainly light snow to
portions of the North Slope.

- Snow will develop at higher elevations, but the moisture plume
is expected to shift eastwards with time, allowing for most of
the snow over the Brooks Range to shift eastwards as well.
Accumulations should remain rather light ranging from 1 to 3
inches depending on elevation.

- Temperatures will hold steady through the first half of the
weekend, with highs in the 30s/40s and lows in the 20s/30s.
High elevations of the Brooks Range tonight could drop to
around 10-20F with wind chills down around 0-10F. Temperatures
warm throug the latter half of the weekend.

&&

.SHORT TERM /THROUGH MONDAY/...
A very active weather pattern has set up across northern Alaska,
with current satellite and radar imagery showing an atmospheric
river moving up from the SW over the Wood Mountains and into the
Interior. Over the past 24 hours, an increasing number of instrument
sites across the Western Interior are approaching an inch of
rain already, with more on the way for Friday as the
atmospheric river and its embedded systems slowly steer eastward
as they displace the ridge over the Gulf of Alaska.

Periods of moderate to heavy rainfall will remain widespread through
Saturday, backed up by a saturated atmospheric column, with
soundings confirming that much of the Interior south of the Brooks
range is saturated up through at least 500 mb, which is helping to
maximize stratiform Bergeron-Findeison driven precip processes.
Coupled with the widespread warm air advection which is displacing
the previous early-season arctic airmass, it is entirely possible
for parts of the central and western interior to see 5-10 year 48
hour average return intervals from this system, with upwards of
25 year ARIs not out of the question for some locations. The
1-2.5 inches of rain expected to fall through Saturday will
bring with it river rises, and while major rivers are likely to
absorb the rainfall without too much difficulty, smaller creeks
and stream could see more substantial rises, with sandbars
potentially becoming covered in water.

The atmospheric river will finally wind down through late Saturday
into Sunday, as a low moving up north along the plume of moisture
cuts off the source - though not before bringing one final round of
moderate to heavy rainfall, along with the chance for some
isolated thunderstorms in the 30 mile country on Saturday.
Sunday will feature a lull in the previous pace of the active
pattern, with the prior system departing off to the N. A weak
warm front moving up in its wake which was spun off of an
occluding low in the western Bering will keep some chances of
rain in the forecast, but rainfall totals will be substantially
lower. A broad area of troughing setting up across northern AK
as we start the new week will set the stage for additional
systems to move through the region. For more information, see
the long term forecast discussion.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
A broad long-wave trough builds over the state in the wake of
the atmospheric river which moved through over the first half of
the weekend. With northern AK positioned on the eastern flank,
prevailing SW flow will enable moisture and shortwaves to
continue moving up into the Interior. The big caveat being that
without the broad plume of moisture associated with an AR, day-
to-day precip totals will be substantially lower. On Tuesday,
the long wave trough is weakened as a ridge builds back across
the Gulf, driven by downstream energy from a strengthening
shortwave S of the area. This shortwave will swiftly strengthen
into a full blown organized low as a strong 140+ kt jet provides
upper level support, albeit its final strength will still be
limited to 990-1000 mb due to the lack of a good source of cold
air to tap into along its NW flank. Confidence is growing in the
general location of the landfall for this new low being south
of the Seward Peninsula, with the most likely location currently
in the general vicinity of the Kuskokwim Delta sometime
Tuesday. As the slow moves up into the interior, expect periods
of widespread rain to return to areas from the Brooks Range
South, with breezy conditions in the vicinity of mountain passes
also a possibility. For the remainder of the week, SW flow
keeps continued chances of more scattered showers and cloud
cover, with the potential for a front to move out of the Bering
late in the week. Temperatures will remain on the more mild
side, as a more maritime airmass keeps high temperatures in the
50s or lower 60s, and low temperatures above freezing.

Coastal Hazard Potential...
A low in the Bering will continue to allow for sustained
southerly flow through the north Bering into the Norton Sound
through Saturday. Due to the long fetch of southerly winds over
open water, water levels could rise 2 to 4 feet above the normal
high tide line in the Norton Sound, and 1 to 2 feet above the
normal high tide line along the Yukon Delta Coast. Water levels
are expected to peak Friday morning and again during the period
of high tide Saturday morning. As a result we have issued a High
Surf Advisory for coastal areas of the eastern Norton Sound
where guidance is showing the highest water level rises at this
time.

&&

.FIRE WEATHER...
Some isolated showers were able to fall across parts of the Upper
Tanana Thursday afternoon, ahead of the strengthening ridge in the
Gulf. With this ridge expected to continue strengthening, this will
continue to minimize the chance for scattered to widespread rain
showers. In addition, this will set up southwesterly flow aloft
which will allow for downsloping across the Upper Tanana. Not only
will this contribute to the little to no precipitation, it will also
help warm maximum temperatures. With temperatures warming to the
upper 60s on Friday, this will also result in a slight decrease in
minimum RH values. With values between 45 and 50 percent seen on
Thursday, values on Friday are expected to be around 40 percent.

Another shortwave will work its way over the ridge from the
southwest, moving over the Upper Tanana Valley Saturday morning.
This will bring the next chance for isolated showers for the first
half of the day. Depending on how much clearing there is to warm the
surface after this system, there is a slight chance for very
isolated thunderstorms Saturday afternoon/evening as a weaker
shortwave follows behind the first.

Looking ahead to the end of the weekend, high temperatures will
continue to be in the mid 60s across the Upper Tanana. A few
additonal shortwaves will continue to move across the Interior as
south/southwest flow is expected to continue aloft.

&&

.HYDROLOGY...
A strong push of moisture across the Western and Central Interior
continues through Saturday. Rainfall totals in excess of 1 inch have
already fallen over parts of Western AK, and rainfall totals of
up to 2.5 inches between Fairbanks, Bettles, and McGrath will
be possible so expect fairly decent rises in local streams and
rivers with sandbars potentially covered. Exact location of
these higher amounts remain uncertain as ensemble members show a
wide range of totals due to varying storm tracks, but models
are still showing the area of heaviest rainfall in the lower
Tanana River Basin and the middle Yukon. Given the saturation of
the atmospheric column, think that the more aggressive model
runs are likely to be closer to accurate regarding precip
totals, with average return intervals of 2 to 5 years possible
throughout much of the central and western interior through the
weekend. Isolated areas could potentially see heavy rainfall
more in line with 10 to even 25 year return intervals, resulting
in significant rises in the smaller headwater streams that feed
the Koyukuk and Middle Yukon Rivers. While there are no
immediate concerns for the main stem rivers in the area, they
will also see significant rises in water levels through the week
as a result of the expected heavy rainfall with sandbars
potentially becoming covered with water.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...High Surf Advisory until 11 AM AKDT Saturday for AKZ822-824.
MARINE...Small Craft Advisory until 7 PM AKDT this evening for PKZ811.
Small Craft Advisory until 6 AM AKDT Saturday for PKZ812-857-
858.
Small Craft Advisory from 1 AM to 6 AM AKDT Saturday for
PKZ813-860.
Small Craft Advisory from 1 PM this afternoon to 6 AM AKDT
Saturday for PKZ814.
Brisk Wind Advisory from 4 PM this afternoon to 6 AM AKDT
Saturday for PKZ814.
Brisk Wind Advisory from 4 AM to 6 AM AKDT Saturday for PKZ815.
Small Craft Advisory from 4 AM to 6 AM AKDT Saturday for
PKZ815.
&&

$$

SYNOPSIS.......SPANN
KEY MESSAGES...SPANN/LANEY
SHORT TERM.....SPANN
LONG TERM......SPANN
COASTAL........LANEY
FIRE WEATHER...TWOMBLY
HYDROLOGY......SPANN/LANEY