994
FXAK69 PAFG 171028
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
228 AM AKDT Mon Jun 17 2024

.SYNOPSIS...
Another warm day is on tap today for most of the Mainland with
temps continuing to run above seasonal norms. Thunderstorm chances
will once again favor higher terrain, although strong
thunderstorms are forecast near the W Alaska Range to the Lower
Yukon Valley today. Wednesday, strong thunderstorms will be
possible from the Central Interior into the Upper Koyukuk Valley
and Yukon Flats. Temps are cooling out west as an arctic trough
digs south.

&&

.DISCUSSION...

Upper Levels and Analysis...
A narrowing 567 ridge axis extends across the state of Alaska,
from SE Alaska all the way to the West Coast. There is an
anomalous 537 dam arctic low over the Chukchi Sea. There is a
shortwave trough moving east across the Brooks Range with areas of
elevated thunderstorms and showers. Some storms are also
occurring over the Arctic waters as of 1 AM this morning. There is
a broad 549 dam NPAC low spanning the Aleutian Chain with a weak
shortwave trough moving across the AKPEN from Kodiak Island.

Model Discussion...
The numerical weather models are doing fairly well with the
general pattern through midweek. The largest discrepancy is with a
migratory shortwave trough currently over the AKPEN, which is
projected to move north and interact with the arctic trough
farther north. The models are showing fairly large dispersion by
Tue afternoon with a whole slew of differing solutions, but the
general trend in all models is to move things faster north by Tue
afternoon, so this forecast will adjust for thunderstorm chances
Tue to be nudged northward, faster. A blend of NAM nest and hi-res
models was favored for winds. A blend of all models was favored
for everything else.

Central and Eastern Interior...
Another warm day today with temps near 80 or slightly above for
most of the S Interior and Yukon Flats. Thunderstorm chances are
higher for the Yukon Flats, especially from Chalkyitsik north,
but otherwise, more isolated thunderstorms today mainly over the
higher terrain. Some storms will be strong along the W Alaska
Range today, as well. The flow aloft turns southwest late this
evening and some storms may drift north off the Alaska Range into
parts of the Tanana Valley, and may continue overnight as showers.

Tuesday, with the mid level flow turning more southwest and a weak
front shifting north, widespread showers and thunderstorms are
expected from the Central Interior highlands northward to the
Upper Koyukuk and Yukon Flats, as well as the Fortymile Uplands
and White Mtns. More isolated thunder activity will be possible
from the Alaska Range to the Tanana Valley, but a few storms may
be strong as CAPE/shear parameters look fairly respectable.

Wednesday, it will still be on the warmer side with more isolated
thunderstorm chances pretty much across the Interior as a
southeast flow develops.

West Coast and Western Interior...
Dry and warm again today except strong thunderstorms late this
afternoon over the W Alaska Range to the Lower Yukon Valley, with
some storms producing a lot of lightning and potential hail. The
area of thunderstorms expands Tuesday across the Interior to the
Brooks Range, with fairly widespread thunderstorm chances, with
the best chance from Galena northward, where some storms will be
quite strong. Meanwhile, an arctic trough is digging south across
the West Coast later today through Tuesday, bringing a chance of
rain showers along the front, along with increasing north winds
and cooler temps. The arctic low moves offshore Wednesday
although showers may persist along with slightly cooler temps.
Expect areas of stratus and some fog to move south with the arctic
trough today and tonight across the NW Arctic, Seward Peninsula,
and Bering Strait.

North Slope and Brooks Range...
A stout arctic low persists over the NW Arctic to Utqiagvik, with
southwest winds and showers. There are even some elevated
thunderstorms tonight as the leading upper disturbance moves east.
Thunderstorms will continue along the front as it shifts to the E
Brooks Range later today. Showers continue over the Arctic coast
mainly from Utqiagvik west through Tue, with high pressure
bringing back possible fog and stratus further east after a couple
of nice days. Northeast winds increase along the coast Tue with
another round of heavy showers with thunderstorms over the Brooks
Range, with that general pattern persisting into Wednesday.

Extended Forecast Days 4-7...
The West Coast arctic low is drifting west Thursday with a low
developing in the Gulf of AK, and a weak Interior ridge persisting
over the Mainland. It does look like the far S Interior to AK
Range will cool down with increasing chances for heavy rain
showers and thunderstorms as easterly waves shift inland. Weak
high pressure aloft will shift farther north and it should be
warming across most of the remainder of the Mainland through the
weekend, with the exception being the Arctic coast where temps
remain seasonal.

Coastal Hazard Potential Days 3 and 4...None.

&&

.FIRE WEATHER...
Scattered wet thunderstorms today over the Lower Yukon to the W
Alaska Range along a thermal low, with another warm and hot day
for most of the Interior. isolated Interior thunderstorms once
again favor the higher terrain. Expect widespread upper 70s to low
80s with another day of lower to mid 20 percent min RHs.

The thermal low shifts north Tuesday and a very active wet
thunderstorm day is expected from the Central Interior highlands
into the Upper Koyukuk and Yukon Flats, as well as the Fortymile
Uplands. We are continuing with scattered wet thunderstorms north
of the Tanana River to the White Mtns and into the Yukon Flats.
Elsewhere, there will be isolated wet thunderstorm chances with
southerly steering flow, but some may be strong in the late
afternoon, from the Alaska Range to the Tanana Valley. Wetting
rain chances are moderate over the Central Interior to W Interior
Tue. Temps are slightly cooler Tue but still running above average
over most of the Interior. A cold front shifting south along the
West Coast tonight will bring much cooler temps for Tue from the
Seward Pen north.

&&

.HYDROLOGY...
No current concerns as rivers over the N Slope are all trending
downward.

&&

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

$$

Ahsenmacher