697
FXAK69 PAFG 241337
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
537 AM AKDT Mon Jun 24 2024

.SYNOPSIS...

A very active pattern will bring the warmest temperatures so far
this summer to much of the Interior on Wednesday and Thursday
while a highly unusual Bering Sea low pressure system brings near
Gale force winds to the Yukon Delta coast on Wednesday. The heat
wave will even extend to the North Slope on Wednesday and
Thursday. Thunderstorms will continue to be active this week, with
relatively dry thunderstorms possible east of Chena Hot Springs
on Wednesday evening.

&&

.DISCUSSION...

Analysis and Model Discussion...

An amplified and impactful 500 mb pattern is set to impact
northern Alaska over the next week. Ridging persists over most of
the area with a tight closed low just north of Utqiagvik north of
the Arctic Coast. This low will retrograde northward, opening the
door for even stronger ridging to build into the Interior and even
north to the Arctic Coast. This will bring high temperatures near
or above 90 degrees to much of the Interior on Wednesday and
Thursday. 80s are even expected north of the Brooks Range
approaching the Arctic Coast. By Wednesday morning, a tight and
powerful vertically stacked closed low will move to near St. Paul
Island. This feature is highly anomalous for this time of year,
and models are progging it at 4 standard deviations from normal.
This feature will bring near Gale force south and southeast winds
to the Yukon Delta on Wednesday morning and 20 mph south and
southeast winds south of the Bering Strait. This will bring even
more rare elevated surf to the region Wednesday through Friday.

As the low transits northward on Thursday and Friday, a sharp
boundary will form from the Northwest Arctic Coast to the central
Alaska Range. This boundary will be the focus for highly active
thunderstorm activity. A shortwave will also bring elevated
thunderstorm activity and the possibility of dry thunderstorms
east of Chena Hot Springs on Wednesday evening.

The 24/00z model suite initialized about 1 decameter too weak on
ridging over the Interior at 500 mb. Models are in excellent
agreement aloft through Thursday morning. We will use a blend of
models for the forecast. We`ll update the Lightning Activity Level
forecast to match latest guidance (a general increase, especially
Wednesday afternoon in the Eastern Interior) and bump down
temperatures a couple of degrees across the Interior tomorrow post
cold front passage.

Central and Eastern Interior...Hot and dry will be the main story
through the work week with isolated thunderstorms and a few areas
of widely scattered thunderstorms. Highs will reach into the low
80s Monday and Tuesday and into the mid to upper 80s with some 90s
possible on Wednesday and Thursday. Highs will likely remain in
the 80s through the weekend. Lows in many locations will struggle
to drop below 60. Thunderstorms will be isolated today and
tomorrow, but widely scattered tomorrow over the Fortymile Upland
and near Eagle. On Wednesday, a shortwave will rotate around the
high and possibly spark off widely scattered thunderstorms over
the eastern Alaska Range and Fortymile Uplands east of Chena Hot
Springs. These thunderstorms look to possibly be mostly dry in
nature. Smoke from the wildfires burning in the Tanana Flats will
likely move into Fairbanks this morning. Smoke may be dense at
times, though conditions should improve by Tuesday night at the
latest.

West Coast and Western Interior...Strong ridging over the Interior
and the influence of the low in the Bering Sea over the West Coast
will create a mix of conditions over the area over the next week. As
the low moves north, expect near Gale force winds and some rain along
the Yukon Delta coast on Wednesday. In the Interior, highs will be
in the mid 70s to lower 80s under mostly sunny skies with areas of
smoke near active fires, with temperatures trending upwards
through Wednesday. Lows will also get warmer each day through
Thursday. Thunderstorms will be widely scattered near McGrath this
afternoon and from McGrath to Lake Minchumina on Tuesday. Storms
will be isolated across the rest of the Interior on Tuesday.
Wednesday and Thursday look to bring additional isolated
thunderstorms.

North Slope and Brooks Range...Patchy fog and low stratus along
the coast this morning will become less and less extensive the
next couple of nights as the closed low aloft moves offshore and
is replaced with ridging. Temperatures will rise each day, with a
full on North Slope heatwave expected starting Wednesday. Highs
will be in the 80s inland, with 60s and 70s along the coast
Wednesday and Thursday. Strong thunderstorms are possible Thursday
over the western Brooks Range. Otherwise, thunderstorms will be
isolated over the eastern Brooks Range each afternoon.

Coastal Hazard Potential Days 3 and 4...The aforementioned low
pressure system in the Bering Sea will bring elevated surf 1 to 3
feet above the normal high tide line along the Yukon Delta coast
as well as south facing shorelines south of the Bering Strait
including Nome. Water will be elevated Wed-Fri with multiple water
level peaks as storm surge values remain fairly constant and tides
go in and out.

&&

.FIRE WEATHER...

Fire weather continues to be a concern with hot and dry conditions
and active thunderstorm days all in the forecast. Today, expect
highs in the mid 70s to low 80s across the Interior. RHs will
reach critical values (<25%) east of Delta Junction. Tuesday will
be a few degrees warmer yet, though RHs will generally remain
above critical values. Wednesday and Thursday are the real
scorchers with highs approaching 90 and min RHs 20-25% east of
Tanana. Could see Red Flag or near Red Flag conditions for
hot/dry/windy Thursday and Friday east of Galena. Otherwise, winds
will remain below 15 mph.

Thunderstorms will be active each day this week. Today, expect
widely scattered thunderstorms from McGrath south to the Western
Alaska Range and isolated thunderstorms elsewhere south of the
Brooks Range and east of Ruby. Tuesday will see widely scattered
thunderstorms from McGrath to Minchumina and over the Fortymile
Uplands with isolated storms across the rest of the Interior and
eastern Brooks Range. Wednesday will feature widely scattered
thunderstorms across the eastern Alaska Range and Fortymile
Uplands. These storms look to be drier in nature under the strong
ridge. Isolated storms are expected across the rest of the
Interior on Wednesday. Thursday and Friday have the potential to
be big lightning days, with most of the activity focused on the
boundary between the ridge and the influence of the low in the
Bering Sea.

&&

.HYDROLOGY...
Recent heavy rains have led to higher water levels along the
Fortymile River, but drier conditions expected over the next
several days will allow water levels to fall this coming week.
Glacial fed rivers including the Tanana may begin to rise as
warming temperatures lead to increased high elevation snowmelt.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...None.
PK...None.
&&

$$

CHRIEST