177
FXAK69 PAFG 192331
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
331 PM AKDT Tue Aug 19 2025

.SYNOPSIS...

A disturbance bringing clouds and rain will continue to push
through eastern Alaska today and tonight, with a strong high
pressure moving in from the north. Wednesday will feature a
seasonably cold morning, with areas of frost possible in the
Central Interior. Clear skies and dry air will help temperatures
warm considerably Wednesday afternoon. Wednesday Night into
Thursday, the next storm system will bring impacts to the West
Coast and Northwest Alaska. Looking ahead, another strong storm
system will potentially impact western portions of the state this
weekend.

&&

.KEY WEATHER MESSAGES...

Central and Eastern Interior...

- A disturbance today will bring scattered showers (40-60%
  chance), maybe a thunderstorm or two (5-10% chance), in the
  Eastern Interior, particularly the Upper Tanana Valley.

- Temperatures will drop into the 30s for much of the Central
  Interior, potentially bringing areas of frost.

- A generally unsettled pattern returns this weekend, with periods
  of light rain and near constant overcast.


West Coast and Western Interior...

- A storm system Wednesday Night into Thursday will bring
  widespread (80-90% chance) rain, strong winds, and the
  potential for minor coastal flooding.

- A second potentially stronger system may bring similar impacts
  to the region this weekend.


North Slope and Brooks Range..

- Sub-freezing temperatures are expected in the Brooks Range
  tonight owing to clear skies, calm winds, and snow that fell
  earlier today.

- A storm system on Thursday will bring widespread rain (70-80%
  chance) to the area, with some locations in the Lisburne
  Peninsula and southern Brooks Range picking up between 0.5" and
  1.0" of precip.

- Another storm system this weekend may bring an additional 1-3
  inches of rain to the Southern Brooks Range and Lisburne
  Peninsula.

&&

.FORECAST ANALYSIS AND DISCUSSION...

...Today and Tonight...

The storm system currently situated over Eastern Alaska will
continue to progress eastward into Northwest Canada. As such,
another day of scattered rain showers (40-60% chance) and a stray
thunderstorm or two (5-10% chance) is on tap for the Eastern
Interior, with the greatest chances for a rumble of thunder in the
Upper Tanana Valley. Behind this system, a post-frontal high
pressure will move in from the northwest, bringing clear skies,
dry air, and calm winds. As such, temperatures are expected to
drop quickly across the Central Interior, with many seeing lows in
the low 30s, potentially upper 20s. With max RH values above 90%
in many spots, areas of frost are possible late tonight into
Wednesday morning.

...Wednesday and Thursday...

By Wednesday, a compact shortwave trough will traverse the Bering
Strait and move into Northwest Alaska. The attendant surface low-
pressure will bring strong south/southwesterly winds to the West
Coast and Western North Slope Wednesday and Wednesday Night.
Sustained winds of 20-30 mph are expected, with gusts up to 40 mph
possible. Wind strength and direction will also be favorable for
high surf/minor coastal flooding for the Northern Yukon Delta and
Norton Sound during High Tide early Thursday Morning. Many
coastal locations between Carolyn is Golovin Bay and Nunam Iqua
will see water levels of 3 to 5 feet above normal high tide. Waves
of 8-12 feet are expected in open waters of the Bering Strait.

Further inland, widespread rain is expected across much of the
Western Interior, Brooks Range and North Slope Wednesday Night
into Thursday. While most will see accumulation of around a
quarter inch, there will be a swath from the Southern Lisburne
Peninsula into the Southern Brooks Range where rainfall totals may
range from 0.5" to 1.0".

Dryer air further east across Central and Eastern Alaska will
help keep rain coverage more spotty and reduce rainfall amounts.
Nonetheless, there will be enough moisture and forcing for ascent
to result in scattered (40-50% chance) light rain showers by
Thursday afternoon in this region.



&&

.FIRE WEATHER...

A dry post-frontal airmass will result in minimum RH values in
the 30s and 40s for much of the Interior and Eastern North Slope
today and tomorrow. Though winds in the Western Interior this
afternoon may be breezy (10-15 mph) out of the north/northwest.
Calm and variable winds are expected across the Central Interior
and Eastern North Slope today, and across the entire Interior
tomorrow with south winds of around 10 mph on the North Slope.
Afterwards, increasing RH, widespread cloud cover, and increasing
potential for rain with the arrival of our next storm system
Wednesday night will create conditions very unfavorable for fire
ignition/growth through the end of this week and into the weekend.
The one exception will be the Upper Tanana Valley, where surface
moisture will have a hard time reaching. As a result, min RH
values here will continue to be in the 30s through the rest of
the week.



&&

.HYDROLOGY...

A storm system Wednesday into Thursday will bring widespread
wetting rain to much of Western and Central Alaska. There will be
a corridor from the Southern Lisburne Peninsula to the Southern
Brooks Range that may see 0.5" to 1.0" by Thursday Night. While no
hydrologic impacts are expected from this storm, it will saturate
soils and set the stage for minor hydrologic impacts with a
second, potentially stronger storm system this weekend. While
there is still uncertainty with the exact track and intensity of
the weekend storm system, there is increasing likelihood of areas,
particularly western portions of the state, that may see 1-3
inches of rain. This will potentially result in areas of minor
flooding, especially the Western Interior and Southern Brooks
Range where the highest QPF amounts are expected with the
Wednesday/Thursday storm system.



&&

.EXTENDED FORECAST DAYS 4-7...

With the amplification of the polar low in the Chukchi Sea,
upper level troughing will become increasingly dominant over the
Bering Sea. This will result in a period of active weather across
much of Alaska, particularly the western two-thirds of the state.
While there is still uncertainty with the exact timing, intensity
and location of the disturbances that will traverse the region
this weekend and into next week, medium range guidance is
converging on a solution that would bring a strong coastal system
to the West Coast this weekend. Widespread heavy rain will be
possible across the Western Interior and Brooks Range Saturday
into Sunday, with another round of minor coastal flooding along
the West Coast as well. Weekend rainfall totals may reach 1-3
inches in some spots, resulting in areas of minor flooding,
particularly for those who see more than 0.75" of rain with the
Wednesday/Thursday storm. Further east, though forcing for ascent
will be strong and overspread the entire state, moisture will
struggle to penetrate into the Interior. As such, weekend rain
amounts should be much lower than out west (under half an inch).
Rain should also be more spotty in nature, with coverage closer to
30-40% as opposed to the 80-90% chance of rain for the western
third of the state.



Coastal Hazard Potential Days 3 and 4...None


&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...High Surf Advisory for AKZ822-824-825.
PK...Small Craft Advisory for PKZ805.
     Small Craft Advisory for PKZ806-810.
     Small Craft Advisory for PKZ807-816-817-854.
     Small Craft Advisory for PKZ811-857.
     Small Craft Advisory for PKZ812-858.
     Small Craft Advisory for PKZ813.
     Small Craft Advisory for PKZ850-853.
     Small Craft Advisory for PKZ851.
     Small Craft Advisory for PKZ856.
     Small Craft Advisory for PKZ859.
     Small Craft Advisory for PKZ860.
&&

$$

Darrah