482
FXAK69 PAFG 191322
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
522 AM AKDT Wed Aug 19 2026

.KEY MESSAGES...
- Temperatures warm into the mid 60s/low 70s Wednesday and Thursday
as a ridge builds into the Central and Eastern Interior. The warmest
temperatures are expected in the Yukon Flats and Upper Tanana
Valley, and the latter will see another couple of days of near-
critical fire weather conditions.

- An isolated thunderstorm or two cannot be ruled out in Fortymile
Country Wednesday and Thursday. Chances for isolated thunderstorms
are more likely as the ridge breaks down on Friday in the Eastern
Interior.

-A Bering Sea low will bring wetting rains into the Central Interior
west of Fairbanks on Friday into Saturday. A low in the Northeast
Gulf of Alaska could bring wetting rains into the Southeastern
Interior Friday evning through Sunday morning, but forecast
certainty is low at this time.

West Coast and Western Interior...
-There is no dry spell in sight for the Northwest Interior,
especially over higher terrain along the Middle Koyukuk, a region
where between 2 and 4 inches have already fallen this week. An
additional 1-2 inches could fall somewhere in the Northwest Interior
by Saturday afternoon, but forecast confidence is low.

-Another Bering Sea low is set to arrive on Friday. There is still
low model uncertainty in its track, but models are in agreement that
it will be weak.Expect northerly/northwesterly wind gusts of up to
40 mph and precipitation totals between 0.5 inches and 1 inch,
especially over higher terrain.

North Slope and Brooks Range...
-A front moves across the North Slope/Brooks Range on Wednesday,
bringing 0.1-0.25 inches of rain over the North Slope and 0.25-0.5
inches in the Brooks Range. There is also a chance for an isolated
thunderstorm or two over the Southeastern Brooks Range Wednesday
afternoon.

-Southerly flow over the Brooks Range will warm temperatures
Thursday and Friday with high  warming into the upper
40s/upper 50s on the coast and mid 60s inland by Friday afternoon.
As southerly flow dies down on Friday afternoon, there is another
chance for afternoon thunderstorms in the Southeastern Brooks Range.

-There is a chance of light snowfall (<1 inch) over the Western and
Central Brooks Range Saturday morning/afternoon as a weak trough
brings instability and colder air from the northeast.

&&

.SYNOPSIS...
Temperatures warm into the upper 60s/low 70s in the Central and
Eastern Interior Wednesday and Thursday, leading to another couple
of days of near-critical fire weather conditions in the Upper Tanana
Valley. Widespread wetting rains could be coming their way this
weekend, but it would require a very specific set of conditions and
model uncertainty far from guarantees these conditions will be met.
Meanwhile on the West Coast and in the Western Interior, isolated
showers continue through Friday, when a weak Bering Sea low brings
another round of more widespread precipitation to the region. There
is also a chance for heavier precipitation to reach almost the
entire Interior next week, but models are having difficulty
accounting for different key features in the pattern.

.&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Weak ridging is starting to build into the Central and Eastern
Interior Wednesday morning, while an upper level low sits over the
Alaska Peninsula. The low will move into and across the Gulf of
Alaska, staying out of our CWA for now, but is a source of
significant forecast uncertainty later on. Ridging will provide a
slight warm-up for the Central and Eastern Interior (widespread
highs in the mid 60s/low 70s) and respite from the showery
conditions for Wednesday and Thursday. Chances for a lightning
strike or two remain in the Upper Tanana Valley, Fortymile Country,
and Eastern Brooks Range if energy from the low in the Gulf moves
over the area around peak heating. Additionally, a weak trough and
associated front swing across the North Slope Wednesday, bringing
another round of rain to the region. Precipitation will range from
just over 0.1 to around 0.25 inches on the North Slope, and up to
0.5 inches over the Northern Brooks Range. Energy stemming from both
areas of lower pressure continues to bring shower activity to the
Western Interior. The Middle Koyukuk, which has already reported 2-4
inches of rainfall in the past 72 hours in some places, will see
another 0.5 inches.

Thursday looks to be the driest day of the week in Northern Alaska.
Ridging keeps widespread showers out of the Central and Eastern
Interior (with the exception of isolated thunderstorms in the Upper
Tanana Valley and Fortymile Country, similar to Wednesday). The
North Slope will see a lull in between vort maxes, keeping showers
isolated and light as well. The Western Interior can`t seem to catch
a break from the showers since shortwaves from a new Bering Sea low
pressure system start to move over the region just after the ones
from the previous low leave.

The aforementioned Bering Sea low moves into the region on Friday.
Both the GFS and Euro ensembles have weakened the system compared to
24 hours ago since they both are now projecting the upper level low
will not close off, preventing the surface low from strengthening.
The West Coast and Western Interior will see precipitation totals
between 0.25 and 0.75 inches, with isolated totals up to 1.25 inches
over terrain. Ensemble members haven`t quite converged on a track
for this system yet, so there is uncertainty in where those higher
totals will fall. This low may potentially close off as it moves
southeast on Saturday, bringing down more troughing into the
Northwest Interior behind it. Though the troughing is relatively
weak, it does bring colder air into Northwest Alaska. If combined
with sufficient moisture, the colder temps could support light
snowfall (<1 inch) in the Western/Central Brooks Range Saturday
morning/afternoon.

The upper level low that has been moving across the Gulf all week
makes it into the northeastern Gulf by Friday/Saturday. This system
could bring a return to wetting rains for the Upper Tanana Valley,
but the pattern is incredibly finicky. Models are in agreement that
the low will make landfall around Yakutat and move northeast through
the Yukon. This would bring moist, southeasterly flow into the Upper
Tanana Valley. However, minor differences in how features develop
and interact with the current environment could determine if the
Upper Tanana sees over an inch of precipitation, or non-wettting
rain, and when this potential precipitation occurs. If the low is
able to stall vaguely north/northeast of the St. Elias Mountains due
a more persistent ridge to the east, the Upper Tanana could see
precipitation totals between 0.25 and 0.5 inches. Another solution
that would favor higher precipitation totals would be if the low
moving over the Bering on Friday is able to phase with this low,
keeping semi-persistent southeasterly flow into the valley for up to
a couple of days. If the ridge is weaker, southeasterly flow will be
much more brief, which could keep totals closer to 0.25 inches. Even
if a decent plume of moisture is able to make it into the Upper
Tanana Valley, there is a decent dry layer at the surface, which
would greatly inhibit the amount of precipitation that would be able
to make it to the surface. As if the pattern wasn`t complicated
enough, there is a lack of model consensus as to when this low moves
onshore, with about 24 hours of spread ranging from Friday afternoon
to Saturday afternoon. A later solution would be more likely to
phase with the low from the Bering, while an earlier solution would
be more likely to be stalled by the ridge. There is more certainty
in chances for isolated thunderstorms in Fortymile Country, the
White Mountains, the Yukon Flats, and the Southeastern Brooks Range
as the ridge moves east into the Yukon, especially if ridge
breakdown occurs in the afternoon hours.

&&

.LONG TERM /SUNDAY THROUGH TUESDAY/...
Early next week a very active and wet pattern will begin to set
up for Northern Alaska. There is however a mix bag on
uncertainty with the upcoming pattern. Ensemble guidance is
showing a strong ridge axis in the Bering Sea being squished and
moved to the southeast towards the Gulf of Alaska as an Arctic
trough moves east into the Bering from the Kamchatka Peninsula.
This squished ridge axis will set up southwesterly flow into the
Bering Sea and then into mainland Alaska. In the Central
Pacific there will be a decaying tropical cyclone. This system
will potentially help to provide the moisture for the
southwesterly flow. This cyclone is where the uncertainty
begins for much of next week.

The aforementioned cyclone will begin to rotate around the North
Pacific High towards the Aleutian Islands. As it moves closer to
the Island chain, a strong arctic low will begin to rotate
through the Bering Sea towards Western Alaska. This arctic low
could potentially tap into the tropical moisture and begin to
advect it towards Western Alaska. While some ensemble members
are showing this as a possibility, some aren`t which is
creating large model spreads of the forecasted rainfall. At Nome
for instance there is nearly a 2 inch spread of qpf between the
25th and 75th percentile within the ECMWF ensemble Sunday night
and through Monday. This uncertainty will continue to carry
eastward towards the Eastern Interior as the arctic low
continues to moves east. While there wont be as much rainfall as
compared to the coastline, there is still a spread of 0.25" to
0.5" of rainfall.

While there remains a lot of uncertainty regarding rainfall
amounts, it looks to be a cooler and wetter start to the work
week across all of Northern Alaska.

Coastal Hazard Potential...
A very weak Bering Sea storm will bring higher waters to the
Southern Seward Peninsula Friday morning during high tide. This
storm could bring an additional 1 to 2 feet of water above the
mean high water mark. This could create some minor beach
erosion, but no flooding is expected with this system.

&&

.FIRE WEATHER...
Cooler weather and isolated to scattered rain showers will keep
fire weather concerns minimal across the Western and Central
Interior. Temperatures will be in the 50s/60s across the region
with the bulk of wetting rains in the Koyukuk Valley. Across the
Eastern Interior however some slightly warmer and drier weather
will make a brief return as weak ridging is building into the
region. Daytime highs in the Tanana Valley and Yukon Flats will
be in the upper 60s with the Upper Tanana Valley in the low 70s.
Conditions will remain dry across the Upper Tanana Valley as
weak downslope flow continues Wednesday. We will see minimum
RHs near 30% with the driest being Dot Lake to the AlCan Border.
If temperatures begin to climb today to around 73/74 instead of
70/71 than we could see RH values begin to approach that
critical threshold of 25%. These warmer temperatures would have
the best chance to occur before 4PM, as we are expecting
increasing cloud cover to begin moving into the region after
4PM.

An isolated thunderstorm will be possible Wednesday and Thursday afternoon
in the Fortymile Country near Chicken as a weak upper-level
energy is moving through the weak ridge. These are not expected
to move into the valleys, but if any mature thunderstorm does
develop we could see gusty outflow winds in the area up to 30
mph. Friday, thunderstorm chances will extend across much of the
Eastern Interior from the Upper Tanana Valley north to the
Brooks Range. While temperatures will be roughly the same as
Wednesday, extensive cloud cover will help to minimum RH values
above 40%.

In the Upper Tanana Valley we could see wetting rains arrive
this weekend as a low in the Northeastern Gulf of Alaska could
bring southeast flow through the valley. These wetting rains
require conditions to align as features aloft are interacting
with each other later this week. If we are able to see wetting
rains into the valley the most likely amounts would be 0.1" to
0.5", but again these rains are highly uncertain. We will
continue to monitor of the next couple of days to see conditions
aloft begin to shake up.

&&

.HYDROLOGY...
The moderate to heavy rainfall in the Koyukuk and Middle Yukon
Valleys have received over the past 48 hours has led to
marginal increases of river levels. Smaller creeks and streams
could still see bankfull conditions over the next couple of
days, but no flooding is currently expected.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...None.
MARINE...None.
&&

$$

KEY MESSAGES...Schlezinger
SYNOPSIS...Schlezinger
SHORT TERM...Schlezinger
LONG TERM...Dennis
FIRE WEATHER...Dennis
HYDROLOGY...Dennis