801
FXAK69 PAFG 052349
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
Issued by National Weather Service Anchorage AK
349 PM AKDT Thu Jun 5 2025

.SYNOPSIS...The transition to a very rare and cold weather pattern
is underway across Northern Alaska as an upper level low has begun
to drop south out of the Arctic. Skies begin to clear across the
West Coast while heavy snow will fall in the Central Brooks Range
at times through Sunday. The North Slope will also see
accumulating snow this weekend. By Sunday, snow levels will be
down to 2000 feet across the central Interior with snow possible
across high terrain as temperatures struggle to reach 50 degrees
across Interior Valleys. Frost possible across Interior valleys
Saturday through Monday mornings before a sharp warm up to more
summerlike conditions is expected by the middle to end of next
week.

&&

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

- Much colder temperatures will move into the area through the
  weekend as snow levels slowly drop to 2000 feet by Sunday.

- Frost possible across valleys Saturday through Monday mornings.

- Rain and snow or all snow possible above 2000 feet elevation by
  Sunday. Accumulating snow possible at Coldfoot, over summits,
  and through Alaska Range passes. See Special Weather Statement
  for details.

- Breezy west/southwest winds across the rest of the Interior
  persist through the weekend.

- Due to very cold temperatures aloft, isolated thunderstorms are
  still expected across the northern and eastern Interior, mainly
  over terrain.

West Coast and Western Interior...

- Isolated thunderstorms this afternoon mainly near the Yukon
  River east of Galena.

- Clearing skies across the West Coast with conditions remaining
  clear through the weekend.

- North-northwest winds 20 to 30 mph with gusts to 45 mph through
  the Bering Strait continue into Friday.

- Temperatures will be well below normal with highs mainly in the
  40s. Frost is likely across Western Interior valleys this
  weekend.

North Slope and Brooks Range...

- Heavy snow is likely in the Brooks Range and north to Toolik
  Lake this week and over the weekend, with the heaviest snow
  likely from Thursday evening through Saturday morning. Another
  round is likely on Sunday night. Expect 6-12" of total
  accumulation.

- Intermittent snow showers are also expected across the North
  Slope and Arctic Coast east of Deadhorse.

- Well below normal temperatures continue with highs around freezing
  and lows mainly in the low 20s.

- Persistent onshore flow results in low stratus and fog
  potential continuing through the week, especially during the
  "night".

- Winds generally 20 mph or less.

&&

.FORECAST ANALYSIS AND DISCUSSION...A highly anomalous cold Arctic
low has begun to drop south over the western Brooks Range,
bringing 500 mb heights as low as 2.5 standard deviations below
the median over the Western Interior by Sunday morning. In other
words, over 99% of the time this time of year, heights are higher.
This is a remarkably rare (and cold!) pattern setup. 850 mb
temperatures will be up to 13 C below normal over portions of the
NW Interior, and will drop below 0 C for all areas except the far
eastern Interior by Sunday morning. As the low drops south,
northerly flow west of the low will bring clearing skies to the
West Coast and far Western Interior while southerly flow with
embedded shortwaves east of the low brings rain and even snow
showers above 2000 feet east of the low. Cold temperatures all the
way up to 500 mb will allow for continued isolated thunderstorms
across the northern and eastern Interior, mainly over terrain.
This pattern largely persists through the short term with no
significant warming expected until the middle of next week.

Models are in good agreement on the overall pattern and just
differ on precip timing and amounts. We will continue to lean more
on the Canadian model as it has been the most consistent and has
verified the best so far as this pattern develops. It also tends
to verify better with systems moving out of the Arctic. Blends
such as the NBM will continue to struggle in this anomalous
pattern due to bias correction from recent seasonable conditions.

&&

.FIRE WEATHER...There are minimal fire weather concerns in the
short term. Temperatures and RHs will be much cooler and wetter
than normal across all areas. Winds will be blustery out of the
southwest with gusts to 25 mph across high terrain in the Interior
through Sunday. Winds will briefly shift to easterly on Saturday
across the central and eastern Interior. Only isolated
thunderstorms are expected across the northern and eastern
Interior today and just across the eastern Interior Friday and
Saturday. Next week, ridging does look to build in and bring
summer-like temperatures for the middle to end of next week. This
ridge only looks to last 3 or 4 days at max, but shortwaves moving
through the ridge may cause increased thunderstorm activity.

&&

.HYDROLOGY...The only breakup concern remaining is the Sag
River. Temperatures remain below normal through the week so break-
up is not expected quite yet. There are no major concerns unless
there is a rapid warm up. Warming is expected toward the middle of
next week, though it is still uncertainty as to how significant it
will be.

Rivers and streams draining the south slopes of the central Brooks
Range including the Koyukuk will see minor rises this week and
weekend, but there are no concerns. Elsewhere, there are also no
concerns.

&&

.EXTENDED FORECAST DAYS 4-7...The extended forecast period will
begin Sunday night with the cold upper low have shifted south to
be over southwest Alaska. This will bring clearing skies to all
but the northeast Interior and North Slope where moisture east of
the low will still be present. Frost possible across Interior
Valleys Monday morning with cold air still present. The low will
move into the Gulf of Alaska by Tuesday with a ridge of high
pressure building from the southwest over the area. This will
bring summer-like conditions to most areas by the middle to end of
next week.

Coastal Hazard Potential Days 3 and 4...None


&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Winter Storm Warning for AKZ809.
PK...Small Craft Advisory for PKZ805-853.
  Small Craft Advisory for PKZ810-811.
  Small Craft Advisory for PKZ852.
&&

$$

Chriest