582
FXAK69 PAFG 242348
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
348 PM AKDT Sun Aug 24 2025

.SYNOPSIS...

Active weather continues as an atmospheric river advects copious
subtropical moisture inland with multiple embedded disturbances.
Both areas of steady rain across the southern interior today track
east into Canada this evening. However, the upper level pattern
amplifies tonight and Monday as an Arctic trough phases with a
~990mb Bering Sea low. This results in increasing rain rates across
the YK Delta tonight that spread north along the West Coast toward
the North Slope on Monday. As the pattern amplifies, increasingly
meridional/Chinook flow across the Alaska Range shifts rainfall
north of Fairbanks by Monday afternoon warmer temperatures and
perhaps some sunshine across the eastern interior. More importantly,
this also brings strong south winds across the western interior
Monday afternoon, the Brooks Ranges Monday night, and across
the AK Range Monday afternoon through Tuesday night.

KEY WEATHER MESSAGES...

Central and Eastern Interior...

- Light to moderate continues across the southern interior through
Monday morning before shifting northwest during the afternoon.

- Heavy rainfall is expected for the Dalton Highway summits and
central Brooks Range Monday morning through Tuesday night with
smaller rivers and streams potentially reaching flood stage.

- Wind advisories are in effect for southerly winds gusting up to 60
mph through Windy Pass, 50 to 55 mph through Isabel Pass, and around
50 mph in Delta Junction. The most likely time frame is between
Monday afternoon and Tuesday night.

- Warmer temperatures and breaks in the cloud cover are possible
Tuesday into Wednesday, particularly near the Canadian border.

West Coast and Western Interior...

- A very wet storm system tracks north toward the Seward Peninsula
tonight through Monday bringing widespread moderate rainfall and
locally heavy rainfall in excess of 2 inches, particularly for the
Nulato Hills and the south-central Brooks Range.

- Wind advisories are also in effect for a broad swath extending
from the YK Delta northward across the western interior with wind
gusts in the 40-50 mph range expected Monday afternoon.

North Slope and Brooks Range..

- Mostly dry weather on Sunday ahead of another round of rain
spreading north of the Brooks Range on Monday.

- South winds gusting up to about 50 mph are expected across the
central and eastern Brooks Range Monday night into Tuesday afternoon.

- Rain may mix with snow or perhaps completely change over at times
this week. Minor accumulations are possible at higher elevations of
the Brooks Range between Point Lay and Anaktuvuk Pass.

FORECAST ANALYSIS AND DISCUSSION...

Steady morning rain across the southern interior shifts east into
Canada this evening and tonight, but the frontal boundary continues
to focus light to moderate rain showers. Convergence and associated
precipitation rates increase along the front Monday morning as a
deepening low pressure tracks northeast across the Bering Sea. This
low pressure is associated with a negatively tilted subtropical
shortwave phasing with an Arctic low. Integrated vapor transport
values are impressive (>1000 kg/ms) within the systems warm sector
and this is likely to result in heavy rainfall rates, especially for
east-central portions of the Brooks Range. EFI values continue to
increase and additional rainfall amounts of 1-3 inches are likely
across a broad swath of the west coast and western interior with
locally higher values >4 inches possible in the Brooks Range.
Impressive IVT and QPF values are associated with a 60-70 kt low
level jet accompanying this systems` warm sector. It`s unclear how
effectively those strong winds aloft will mix to the surface, but it
won`t take much to reach advisory criteria of 40 mph. Therefore,
wind advisories were issues for a broad swath of the western
interior from Holy Cross toward Huslia in addition to both major
mountain ranges. EPS probabilities for 40 mph gusts are greater than
40% across the majority of the western interior with >90% bullseyes
over areas of higher terrain, which lines up with impressive EFI
values for both wind and QPF. This system leaves a trailing frontal
boundary/atmospheric river allowing for persistent light to moderate
rainfall rates that continue through Wednesday. A final aspect of
this system is the chance for accumulating snowfall across the
northern Brooks Range foothills as cold air deepens behind Monday`s
low pressure. Relatively warm ground temperatures should be
difficult to overcome, but if steady snow materializes -most likely
on Tuesday- then a few inches of wet snow cannot be ruled out.

FIRE WEATHER...

Fire weather concerns will be very low across the state with the
exception for the Upper Tanana Valley and adjacent upland areas. Min
RH values dip into the 30s at valley locations each day this week.
Southerly winds increase across the Alaska Range including Isabel
Pass on Monday with gusts up to 60 mph expected on Monday and
Tuesday. Warming temperatures and less cloud cover should allow for
lower RH across a broader portion of the eastern interior on Tuesday
and Wednesday.

HYDROLOGY...

River flood watches were issued for the tributaries of the Koyukuk
and Kobuk Rivers with a hydrologic outlook remaining in effect for
the majority of northwestern Alaska. There is one primary round of
heavy precipitation remaining associated with a strong storm lifting
northeast along the West Coast on Monday, but areas of light to
moderate rain continue through at least Friday. This final round is
associated with a deepening low spinning up the West Coast on Monday
and spreads across the North Slope on Tuesday. Widespread additional
rainfall amounts of 1 to 3 inches are expected by Tuesday evening.
Locally higher amounts in excess of 4 inches are possible where
rainfall is most persistent, particularly at higher elevations of
the West Coast and Western Interior. Furthermore, snow levels will
be relatively high for this event; above 8000 feet allowing for high
elevation glacier melt. Additional rainfall is possible through the
end of the week (heaviest south of the Alaska Range) and rising
water levels are expected for most interior rivers.

EXTENDED FORECAST DAYS 4-7....No change from the previous discussion
Previous Discussion issued at 4:37am AKDT on Sun Aug 24...

Chinooking conditions will continue across the Alaska Range through
the end of the week with southerly flow continuing and the trough
out west continuing to amplify. This will continue to keep winds
gusty through the Alaska Range. Models are hinting at a cold front
moving NE out of the upper Kuskokwim on Thursday, in association
with a strong shortwave embedded within the trough. A chance for a
thunderstorm cannot be ruled out as a decent amount of CAPE is
expected to accompany this front. Cool and wet conditions are
expected to continue through the rest of the week and into the
weekend with broad N-S troughing across the western portion of the
state.

Coastal Hazard Potential Days 3 and 4...

A ~990 mb low pressure tracks from near St. Matthew Island Monday
morning to near Kotzebue by Monday evening. The most likely outcome
is water levels below high surf advisory criteria. However, there`s
a low chance for water levels reaching criteria late Monday into
Tuesday if a deeper and farther west low track materializes.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Wind Advisory for AKZ837-847-849.
     Flood Watch for AKZ812-813-819.
PK...Gale Warning for PKZ801.
     Small Craft Advisory for PKZ802-806-856.
     Gale Warning for PKZ803.
     Gale Warning for PKZ804-854.
     Small Craft Advisory for PKZ805.
     Small Craft Advisory for PKZ807-852-853.
     Small Craft Advisory for PKZ813.
     Small Craft Advisory for PKZ816-817-851.
     Gale Warning for PKZ850.
     Small Craft Advisory for PKZ858.
     Small Craft Advisory for PKZ859.
     Small Craft Advisory for PKZ860.
&&

$$
EK