425
FXAK69 PAFG 202245
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
245 PM AKDT Wed Aug 20 2025

.SYNOPSIS...

Our next storm system is expected to bring widespread rain (80-90%
chance) and gusty winds to portions of Northwest Alaska tonight
through tomorrow. A High Surf Advisory is in effect for the
Norton Sound and Northern Coastal Yukon Delta from 4AM AKDT
through 1PM AKDT tomorrow. A second storm system this weekend will
impact these same general locations again with gusty winds and
widespread rain possible. This active pattern is expected to
expand eastward into the rest Central and Eastern Alaska and
persist through much of next week.


&&

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

- Today will be mild and dry, with skies clearing from west to
  east and highs in the 60s.

- Tomorrow, a storm system will bring scattered (60-70% chance)
  rain showers to much of the Central Interior, and more isolated
  (30-40% chance) showers in the Eastern Interior.

- A more active pattern will bring multiple chances (40-70%) for
  rain the end of this weekend into next week. The highest
  rainfall chances and amounts will be in the Central Interior.


West Coast and Western Interior...

- A storm system will bring rain (90-100% chance), high surf, and
  gusty winds up to 40 mph (particularly coast areas) today
  through tomorrow.

- A second storm system this weekend will bring another round of
  rain and gusty winds to the Western Interior and West Coast.
  High surf along the West Coast is also expected with this
  system.

- An active pattern will bring multiple additional chances
  (40-70%) for rain through most of next week. Heavy rainfall will
  be possible, with isolated spots seeing up to 3-5 inches of rain.

North Slope and Brooks Range..

- A storm system will bring rain and gusty winds to the region
  tonight through tomorrow. Rain/snow mix will be possible in the
  higher elevations of the Brooks Range.

- A more active pattern will begin with the arrival of another
  storm system this weekend. There will be multiple chances for
  rain (snow in the higher elevations) and gusty winds well into
  next week.


&&

.FORECAST ANALYSIS AND DISCUSSION...

The upper-level flow regime today features a compact shortwave
positioned over the Eastern Alaska Range, a ridge building into
Central Alaska, and an approaching trough from the Northern Bering
Sea.

Forcing for ascent from the compact shortwave over the Eastern
Alaska Range continues to allow cloud cover to persist across much
of the eastern third of Alaska. As ridging, and subsequently
synoptic scale subsidence, expands northeastward, clouds should
slow dissipate from west to east, aided by diurnal heating/mixing.
As such, the clearing skies and dry airmass in place will help
temperatures warm into the 60s this afternoon, with upper 50s in
the Eastern North Slope.

Further west, the approach of our next storm system is bringing
increasing cloud cover to much of West-Central and Northwest
Alaska. Scattered rain showers extending from the Yukon Delta
northward into the Seward Peninsula are expected to expand in
coverage to the north and east, and increase in intensity as the
primary vort max approaches the region from the west this evening.
Strong forcing for ascent aided by upslope flow (primarily in the
Southern Seward Peninsula and the Southern Brooks Range) will
allow for substantial rainfall amounts through tomorrow, with
isolated spots of 1 to 1.5 inches of rain possible. However, most
will see more modest rainfall totals with this storm system,
ranging from 0.25 to 0.75 inches.

A strong surface pressure gradient will bring gusty winds with
this system as well. Southwesterly winds of 20-30 mph, gusting to
40 mph will result in high surf along the West Coast, particularly
in the Norton Sound where water levels will likely range 3 to 5
feet above normal high tide tomorrow morning. Further east, even
though rain chances diminish, strong winds at higher elevations
are expected, with gusts of 35-40 mph possible in the White
Mountains, and gusts of 45-55 mph possible in the Brooks Range
tonight into tomorrow.

As this storm system progresses east-northeastward across the
state tomorrow and into Friday, low-level moisture will struggle
to push into the Interior, resulting in more isolated rain showers
(30-40% chance) for East-Central and Northeast Alaska Thursday
Night into Friday. With the lack of any strong fronts, temperatures
will remain near normal for the rest of the week, with 60s for
highs in the Interior, 50s for highs on the North Slope and West
Coast, and 40s on the North Coast.



&&

.FIRE WEATHER...

With multiple rounds of rain and RH values remaining above 50
percent. Fire weather concerns are very low at this time across
the forecast area with the exception of the Upper Tanana Valley.
While weather conditions will still be unfavorable for fire
growth, low-level moisture will struggle to reach this part of the
state. As such, minimum RH values will be in the upper 30s and
low 40s for the rest of the week. With the arrival of a stronger
storm system by this weekend, rain chances and higher humidity
levels will return to the Upper Tanana Valley.

&&

.HYDROLOGY...

Multiple rounds of rain are expected across large swaths of the
state over the next week. The first main round of rain will
extend from the West Coast northeast into the Brooks Range
tonight through tomorrow night. This weekend, a much larger area
of the state may see rain, with the western two-thirds of the
state potentially seeing large swaths of 0.25" to 1" of rain. By
this weekend, there will be two area to watch: 1) the Southern
Seward Peninsula and 2) the Southern Brooks Range. Both of these
locations may see localized rainfall amounts as high as 2-4
inches by the end of this weekend. Fortunately, rivers in this
area (namely the Kobuk and Koyukuk) are already well below flood
stage and are not expected to approach flood stage as water
levels should only rise a few feet in response to weekend rains.
The greatest area of concern for potential minor flooding impacts
this weekend will be smaller watersheds like creeks and streams
anywhere from the Seward Peninsula northeast towards the Central
Brooks Range.


&&

.EXTENDED FORECAST DAYS 4-7...

With the arrival of another strong coastal system this weekend, a
more active pattern will commence across the state with multiple
rounds of clouds, rain, snow at higher elevations, and gusty
winds heading into next week. Unfortunately, there is substantial
run to run variability amongst models, and disagreement amongst
medium range guidance with regards to the location, exact
intensity, and timing of disturbances during this time frame.
Regardless, there is increasing confidence in another strong
disturbance bringing widespread rain (70-80% chance) to the
western two-thirds of the state, in addition to wind gusts of up
to 40 mph and high surf along the West Coast this weekend.


.Coastal Hazard Potential Days 3 and 4...

It is becoming increasingly likely that another strong coastal
storm will bring wind gusts up to 40 mph and high surf to portions
of the West Coast this weekend.


&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...High Surf Advisory for AKZ822-824-825.
PK...Small Craft Advisory for PKZ801.
     Small Craft Advisory for PKZ802.
     Small Craft Advisory for PKZ803.
     Small Craft Advisory for PKZ804.
     Small Craft Advisory for PKZ805.
     Small Craft Advisory for PKZ806-816-851-854.
     Small Craft Advisory for PKZ807-810-856.
     Small Craft Advisory for PKZ808-855.
     Small Craft Advisory for PKZ809.
     Small Craft Advisory for PKZ811-812-817-850-857-858.
     Small Craft Advisory for PKZ813-860.
     Small Craft Advisory for PKZ814.
     Small Craft Advisory for PKZ852.
     Small Craft Advisory for PKZ853.
     Small Craft Advisory for PKZ859.
     Small Craft Advisory for PKZ861.
&&

$$

Darrah