923
FXAK69 PAFG 011048 CCA
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
201 AM AKDT Mon Jul 1 2024

.SYNOPSIS...
More warm temps today with increasing southwest winds across the
Mainland as a strong front moves toward the NW Arctic Coast. More
thunderstorms can be expected today over the Interior, focused
over the higher elevation terrain, but possible even in the
valleys. Tuesday, temps cool back to seasonal norms and winds
increase from the southwest. Wildfires continue to remain very
active and will still be very active, so smoke will continue to be
an issue, however, there is a good chance air quality over most
of the Interior improves with increasing ventilation from
southwest winds at the surface and aloft. Rain is still projected
by the latter half of the week for the Interior.

&&

.DISCUSSION...

Upper Levels and Analysis...
There is a narrow Interior ridge stretching from east to west
across the S Interior, with heights around 568 dam. There is a 543
dam low over the AKPEN with another arctic trough over near Banks
Island in the arctic, with heights around 524 dam. There is a
mobile shortwave moving east into the Chukotsk Peninsula. At the
surface, there is a remnant thermal trough over the Yukon Flats at
1005 mb. An easterly wave is moving across SW Alaska with an
active region of thunderstorms associated with it. Some fills the
S Interior from several active wildfires.

Model Discussion...
The models are continuing to deal with the general synoptic scale
flow through the end of the week. Smaller scale details
differences emerge, especially today and tonight with a little
ripple of energy aloft moving over the ridge, into the E Interior.
For now, we are favoring a blend of all models to capture the
general flow, as there is a fairly broad footprint of instability
still in place, and models struggle with ridges aloft breaking
down. The general trend remains, however, that temps are cooling
through the week, with increasing southwest winds and less chances
for thunderstorms after today, and then no thunderstorms after
Tuesday with increasing chances for rainfall by the end of the
week. For winds, we favored the NAM nest which supports the
strongest southwest winds on Tue, then the NAM 12 thereafter for
its depiction of winds.

Central and Eastern Interior...
Today begins the gradual cooldown, although temps will still be
warmer than seasonal norms with general upper 70s over the
Interior, and some spots hitting low 80s. Isolated thunderstorms
are again possible today over the entire Interior, but once again
favoring higher elevation terrain. Some storms may move down into
the valleys, but the steering flow is fairly weak. A "cool" front
has moved across the Alaska Range with south winds, and that front
will shift north and bring in broad southwest winds this afternoon
around 5 to 10 mph. Smoke will remain dense through this morning,
and then there will likely be some improvement in air quality,
although very active wildfires will continue to flare up and bring
some overnight again.

Tuesday, is cooler again with widespread seasonal temps in the mid
70s, a few 80s still over the Yukon Flats. A few higher terrain
showers and an isolated thunderstorm are possible, but the bigger
story will be increasing southwest winds again, 10 to 20 mph, with
the highest winds of 15 to 25 mph with gusts to 30 mph over the
Yukon Flats and across the Dalton Highway corridor. Winds really
never end and will blow a bit overnight, and then Wednesday, winds
crank up some more with gusts as high as 40 mph over the Yukon
Flats, and gusts to 30 mph over the S Interior and White Mtns.
Rain will be moving across the Interior from south to north on
Wednesday, reaching the S Interior and AK Range by Wednesday
evening.

West Coast and Western Interior...
A batch of rain showers and isolated thunderstorms this morning
will continue moving across the Lower Yukon Valley and then fall
apart by this afternoon. More afternoon isolated thunderstorms are
possible over the Interior and up to the W Brooks Range,
otherwise, it will be another warm day with temps overall in the
70s, but a few degrees cooler than yesterday.

Attention turns to a strong gale force front moving to the NW
Arctic early Tuesday morning, and then shifting inland Tuesday
evening. This front will bring a continuous period of southwest
winds to 25 to 35 mph and periods of rainfall through the weekend.
Rainfall amounts will be 2 to 4 inches over the SW brooks Range
with a general 1 to 2 inches elsewhere, by late weekend. In
addition, expect elevated water levels of 2 to 3 feet and high
wave action along the West Coast, from Norton Sound to the Chukchi
coast.

North Slope and Brooks Range...
High pressure continues along the coast through tonight with light
onshore winds and periods of stratus and fog, with an isolated
thunderstorm possible over the Brooks Range. Tuesday is a big
change with a fast moving front shifting east, bringing southwest
winds 15 to 30 mph and rainfall, which will move from the NW
Arctic and reach the E Arctic and Brooks Range by Tue night. There
will be a break in rainfall with intermittent showers Wed night
into Thursday before more rainfall commences into Friday. Rainfall
amounts will range from 2 to 4 inches over the W brooks Range to
0.5 to 1 inch elsewhere, with 1 to 2 inches over the E Brooks
Range.

Extended Forecast Days 4-7...
Broad zonal westerly flow is in place beginning the 4th of July,
with the next batch of heavier rainfall moving into the West Coast
and shifting into the Interior Thursday and Thursday night. Friday
continues to be wet with periodic rainfall continuing through the
weekend. Southwest winds are breezy through Friday then slowly
diminish for the weekend. Temps will not be cold, but will be
below seasonal norms through the weekend.

Coastal Hazard Potential Days 3 and 4...Strong southwest winds to
gale force will bring elevated water levels of 2 to 3 feet above
the normal high tideline from Norton Sound to the Chukchi coast
beginning Tue and lasting into late week.


&&

.FIRE WEATHER...
Very active fire weather conditions remain in place through
Wednesday, as the upper ridge axis breaks down and the flow
becomes more westerly. Today, expect the first day of southwest
winds to develop by this afternoon, with 5 to 10 mph across most
of the Interior. Isolated wet thunderstorms with an area of widely
scattered thunderstorms are possible from the White Mtns to the
Fortymile Uplands. The Alaska Range does not look very active
with south winds in place now, but a stray thunderstorm can not be
ruled out. Steering winds will be northwest this evening over the
Interior highlands, so some storms may move off the higher terrain
into the valleys. Temps are mid to upper 70s over the S Interior,
with near 80 over the Yukon Flats, or about 3 to 6 degrees cooler
with minimum RHs a 5 to 10 percentage points higher, with the
southwest winds bringing in a marginally more moist airmass. The
lone holdout for driest airmass will be the N Interior.

Tuesday is drying out some with increased southwest winds of 8 to
12 mph over most of the Interior, and 10 to 15 mph over the N
Interior, and 15 to 20 mph over the Yukon Flats and Upper Koyukuk
Valley. Critical fire weather conditions look likely over the
northern half of the Interior, as temps will be around 75 to 80,
and minimum RH in the upper 20s to near 30 %. A fire weather
watch of possible red flag product is possible, although as
stated, minimum RH looks like it may stay above 25 percent.

The gradient continues to increase overnight, thus winds will only
weaken partially and likely remain mixed out from the Fairbanks
area northward. Winds on Wednesday are stronger yet, likely
widespread 10 to 15 mph, and 15 to 25 mph and gusts to 35 mph over
the Yukon Flats and Dalton Highway corridor, and into the S Brooks
Range slopes. However, temps are falling and precipitation will
be possible by Wednesday afternoon in the form of rainfall, so
minimum RH looks to be higher, into the upper 30 to low 40 %
range.

The onset of wetting rains looks fairly low through Wednesday,
with increasing chances by Wednesday night, and high chances on
Thursday and Thursday night. The lone holdout will be the Yukon
Flats which will see downslope drying and little in the form of
rainfall.

&&

.HYDROLOGY...
Glacial fed rivers including the Tanana are slowly rising as
warming temperatures lead to increased high elevation snowmelt and
glacial melt.

Beginning next week around Wednesday, heavy rainfall will move
across the W Brooks Range with 2 to 4 inches of rainfall through
next weekend, with 0.75 to 1.5 inches over parts of the Interior.
Expect river rises with this amount of water across the Mainland.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Dense Smoke Advisory for AKZ834-837-839>844.
PK...Small Craft Advisory for PKZ806-807.
     Small Craft Advisory for PKZ811-816-817-854-857.
     Small Craft Advisory for PKZ851.
     Small Craft Advisory for PKZ856.
     Brisk Wind Advisory for PKZ859.

&&

$$

Ahsenmacher