Flooding and High Wind in Alaska, August 26 to 31, 2025

Northern Alaska Forecast Discussion...UPDATED
National Weather Service Fairbanks AK
450 AM AKDT Tue Aug 26 2025

...UPDATE HAS BEEN MADE TO THE HYDROLOGY SECTION...

.SYNOPSIS...
Active weather continues for a good portion of the northern and
western part of the state through the weekend. Rain from the
previous coastal system will begin to transition to a wintry mix
over the Central Brooks Range Tuesday night, shifting off to the
west by Wednesday night as another 995mb surface low moves up the
West Coast. The Western Interior will continue to see good chances
for widespread rainfall with a deformation zone expected to form
across the area by Thursday night. Breezy gap winds will continue
through the Alaska Range with the upper-level patterns beginning
to shift more southerly and multiple shortwaves moving over the
Range.

&&

.KEY WEATHER MESSAGES...
Central and Eastern Interior...
- Heavy rainfall will continue for the Dalton Highway summits and
  central Brooks Range through Tuesday night with smaller rivers
  and streams potentially reaching flood stage. Additional rain
  accumulations through Tuesday night are forecasted to be between
  1" and 3".

- 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 this afternoon and Tuesday night.

- Warmer temperatures and breaks in the cloud cover are possible
  Tuesday into Wednesday, for Fortymile Country and the Upper
  Tanana.

West Coast and Western Interior...
- Precipitation will continue for the Western Interior today and
  Wednesday, with additional rainfall ranging between 0.5" and
  1.75". The heaviest amounts will be from Huslia, to McGrath, to
  Holy Cross.

North Slope and Brooks Range..
- Snow has begun to mix in with the rain. Not much in terms of
  accumulation is expected today. However minor accumulation are
  possible at the higher elevations along the Brooks Range from
  Point Lay to Anaktuvuk Pass.

- South winds gusting up to about 50 mph are expected across the
  central and eastern Brooks Range through this afternoon.

- A glaze up to 0.1" of ice is possible along Anaktuvuk Pass and
  the north side of the Brooks Range along the Dalton Hwy
  Corridor. This accumulation is expected from Tuesday night
  through Thursday morning.

- Chances for wintry precipitation will continue across the
  Brooks Range through the end of the week.

&&

.FORECAST ANALYSIS AND DISCUSSION...
Broad, deep Arctic troughing remains in place over the West Coast
and ridging over Canada. This is creating a south/southwesterly
upper-level pattern for the lower third of the state. The
remnants from the previous coastal system is continuing to
progress over the Brooks Range, providing widespread rain showers
across the N. Slope. Cold air will begin to be advected in from
the north, with the aid of a closed low circulating in the Arctic,
transitioning the rain to a wintry mix beginning late Tuesday
night. The best chance for this will be along Anaktuvuk Pass to
the north side of the Brooks Range along the Dalton Hwy Corridor.
These wintry chances will slowly shift west beginning Wednesday
night. Meanwhile, a 995mb surface low will slowly be moving up the
West Coast Wednesday, eventually reaching the western Brooks
Range by Wednesday night and begin tapping into the cold Arctic
air and continuing the chances for the wintry mix along the
Western Brooks Range.

The southwesterly flow that has been set up along the Central
Interior will remain in place with the ridging expected to hold up
over Canada. The surface low, previously mentioned, will continue
to help bring in moisture and energy across the area keeping the
precipitation across the area ongoing. A line of energy will be
caught up in the 995mb's circulation and set up a deformation band
from the Central Brooks Range down to the Upper Kuskokwim. This
will be the main driver for the more widespread rainfall beginning
Thursday and persisting through the weekend.

The upper-level flow over the Alaska Range continues to be out of
the southwest, providing chinooking conditions to the Southern
and Eastern portions of the Interior. This will continue over the
next couple of days. Some weak waves of energy will be embedded
with the deformation zone, bringing some slight chances for
showers across the Eastern Interior beginning Thursday morning. At
the same time, the upper-level pattern will be shifting more
southerly, which could provide additional chances for gusty gap
wind flow as these shortwaves move over the Alaska Range.

&&

.FIRE WEATHER...No change from the previous discussion
Previous Discussion issued at 1:36pm AKDT on Mon Aug 25...

Wetting rains will continue to put a damper on fire weather
concerns this week for most areas. The exception will be through
the upper Tanana Valley where min RH values will still manage to
dip into the 30's through at least Thursday. Strong winds will
continue through the Alaska Range gaps through Tuesday with breezy
conditions continuing across the higher terrain the rest of the
week in response to several disturbances tracking north through
the western zones

&&

.HYDROLOGY...

A river flood warning is in effect for Slate Creek in Coldfoot,
Alaska, between mile markers 175 and 176. At 3:15am the stage was
20.4 feet. Between 3 and 3.5 inches of rain have fallen.
Additional rainfall amounts of 1.5 to 2.5 inches are possible.

River flood watches will continue through Wednesday morning for
the tributaries of the Koyukuk and Kobuk Rivers as well as the
southern Seward Peninsula and eastern Norton Sound coastline. A
new hydrologic outlook is also in effect for portions of the
Central Interior where higher flows are expected along the Chena
River as a result of recent heavy rainfall. While the bulk of the
heavy rainfall has shifted north, areas of light to moderate rain
will continue through at least Friday. Additional rainfall amounts
of 1 to 2 inches are are still possible through tonight along the
south slopes of the Brooks Range with locally higher amounts are
where rainfall is most persistent, particularly at higher
elevations. Furthermore, snow levels will be relatively high for
this event; above 8000 feet allowing for high elevation glacier
melt.

&&

.EXTENDED FORECAST DAYS 4-7...No change from the previous discussion
Previous Discussion issued at 1:36pm AKDT on Mon Aug 25...

Broad Arctic troughing will continue across western areas into
the upcoming weekend. The primary focus throughout the extended
period will be a strong surface low tracking north through the
Bering and into the southern Chukchi Sea Saturday and Sunday.
While the exact track of the low will determine specif impacts,it
does appear that another round of moderate to potentially heavy
rainfall will occur over the west coast and parts of the western
interior. In addition, strong winds and high surf will be possible
along the coast from the Yukon Delta northwards to the Seward
Peninsula.
Coastal Hazard Potential Days 3 and 4...None

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Wind Advisory for AKZ847-849.
     Wind Advisory for AKZ828>830-852.
     Flood Watch for AKZ812-813-819-822>824.
	 Flood Warning for AKZ812.
     Winter Weather Advisory for AKZ804.
     Winter Storm Warning for AKZ808-809.
PK...Small Craft Advisory for PKZ854.
&&

Twombly