539
FXAK69 PAFG 182228
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
228 PM AKDT Tue Jun 18 2024

.SYNOPSIS...

Ridging over the Interior is bringing summer conditions to most of
northern Alaska. High temperatures will be mainly in the 70s
through the rest of the week, with a few 80s in the Yukon Flats
today and tomorrow. Isolated to scattered thunderstorms are
expected each afternoon. Seasonable and mainly dry conditions are
expected for the West Coast and the North Slope as well.

&&

.DISCUSSION...

Upper Level Analysis...

A closed upper-level low is situated over the Chukchi Sea this
afternoon, while broad ridging extends up from Western Canada into
Interior Alaska. A shortwave trough is lifting northward toward
the central and eastern Brooks Range, continues to support
showers and thunderstorms roughly along a line from Huslia to the
Yukon Flats.

Surface Analysis...

A trough extending over much of northwest Alaska is drawing
northerly winds across the Chukchi Sea southward through the
Bering Strait, with gusty south to southwesterly winds developing
along portions of the West Coast and across much of the Western
Interior. Despite generally onshore flow along the Arctic coast,
stratus and fog continues to mix out through the day. Much warmer
conditions with temperatures in the 70s and dew points in the
upper 40s to low 50s have allowed for developing scattered to
numerous rain showers and thunderstorms in the Eastern Interior.

Central and Eastern Interior...

Temperatures will peak broadly in the mid to upper 70s this
afternoon, with areas in the Yukon Flats likely reaching 80.
Scattered thunderstorms continue this evening from the Upper
Koyukuk Valley east through the Yukon Flats and northern portions
of Fortymile Country. Elsewhere, expecting widely scattered
thunderstorms, with isolated thunderstorms possibly moving into
the Fairbanks area tonight as they track north from the Alaska
Range. A shift to southerly winds is possible behind these storms,
which may bring in smoke from the McDonald Fire. Upper-level
ridging gradually shifts north as a series of shortwaves try to
work northward across the Alaska Range. Expect a slight cooling
trend as high temperatures slowly decrease into the low to mid
70s through the end of the week, with thunderstorm activity
trending down as well. High pressure builds along the Arctic
coast, bringing a shift from southwesterly to northeasterly winds,
which could gust up to 25 mph in the Yukon Flats Thursday and
Friday afternoon/evening.

West Coast and Western Interior...

Scattered thunderstorms continue this evening from Galena
northward, with isolated to widely scattered thunderstorms
elsewhere across the Western Interior. Thunderstorm activity will
be lower the rest of the week, with generally isolated
thunderstorms limited to the Western Interior. From the northern
Seward Peninsula north, a deep upper low keeps conditions cloudy
and cool, with a chance of rain (and some snow) showers through
this evening. The upper low retreats west over Chukotka for
Wednesday, allowing the upper-level ridge to extend west.
Temperatures warm up heading into the end of the week, most
notably allowing the Kobuk Valley to see highs in the 70s on
Thursday and Friday.

North Slope and Brooks Range...

Northeasterly onshore flow will continue to bring stratus and fog
along the Arctic coast each night, with offshore flow just off the
surface afforded by the upper low over the Chukchi Sea
contributing to clearing skies during the day. The upper low
retreats westward through the week as high pressure builds along
the coast, bringing deeper onshore flow and more persistent
fog/stratus by Thursday. The best chance for thunderstorms in the
short term is this afternoon/evening, with widely scattered
thunderstorms expected on the south side of the Brooks Range.
Otherwise, thunderstorm risk remains isolated and will be confined
primarily to the Brooks Range each day.

Extended Forecast Days 4-7...

Forecast models are in agreement that the ridge in place over the
interior will weaken over the weekend. Models diverge early next
week, but generally indicate a continuation of near to slightly
above normal temperatures across most of northern Alaska. Drier
conditions across the interior and West Coast are likely this
weekend through the middle of next week. This will bring continued
fire weather concerns.

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

&&

.FIRE WEATHER...

Conditions across the Interior will be a few degrees cooler
with 3-5% higher RH than yesterday. Wed will be slightly drier
but with similar temperatures to today. There will be slight
warming and drying on Thu, with very warm conditions continuing
into the weekend. Expect today to be a banner day for
thunderstorms with more lightning strikes over Northern AK than
what occurred Mon, with the lightning further NE than Mon.

Thunderstorms this evening will be isolated across most of
northern Alaska except the coastlines, but widely scattered across
the Alaska Range, eastern interior, and north of Fairbanks to the
south slopes of the Brooks Range. Thunderstorms will be scattered
from Chicken to Eagle and from the Yukon Flats west to near
Huslia. Expect the scattered thunderstorms to have frequent
lightning, brief heavy rain, winds gusting to 30 mph and 1/2 inch
hail. Wed will have isolated thunderstorms over much of the
Interior through late Wed night, with widely scattered PM
thunderstorms east of Tanana and Bettles Wed PM. There could be
frequent lightning, gusty winds and small hail with the widely
scattered thunderstorms East of Tanana and Bettles. Thu will see
isolated thunderstorms over all of the Interior through the day,
with widely scattered thunderstorms east of Red Dog to Nikolai.

&&

.HYDROLOGY...

River levels on the North Slope continue to fall. No widespread
flooding is expected, but will need to keep an eye on slow moving
thunderstorms across the Northern and Eastern Interior today where
occur over steep terrain. The same goes for the SE Interior and
AK Range on Thu PM when increasing numbers of thunderstorms could
fire up there.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Red Flag Warning for AKZ931>933.
     Dense Smoke Advisory for AKZ840.
PK...Small Craft Advisory for PKZ806-854.
     Small Craft Advisory for PKZ812.
     Brisk Wind Advisory for PKZ813-859.
     Small Craft Advisory for PKZ858.
&&

$$

CQ/JC