934
FXAK69 PAFG 082050
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
1250 PM AKDT Mon Jul 8 2024

.SYNOPSIS... Cool and wet pattern will gradually moderate over
the E Interior the next few days, but it will stay quite wet out
west where another multi-day rainfall is expected, beginning later
this afternoon. Rain will move into the Interior as far east as
the Fairbanks area tonight and Tuesday morning before it begins
warming back to seasonal norms (mid 70s) by Wednesday.

&&

.DISCUSSION...

Upper Levels and Analysis...
A strong and anomalous 500 MB low for this time of year is near
the Arctic coast with heights around 534 dam. A secondary
shortwave trough moving into the Yukon Flats this afternoon and
tonight. There is a shortwave trough over E Siberia with heights
around 553 dam, with the leading edge front moving through the
Bering Strait this afternoon. There is a vigorous 535 dam arctic
"bowling ball" low quickly diving south from the North Pole which
will strengthen to 530 dam Monday evening. There is a 546 dam low
centered over the S Gulf of Alaska with a fairly spiral form
looking marine occlusion on satellite. The main surface low is a
weak 1010 mb low over the Yukon Flats, with a 1013 mb high over
the Chukchi Sea.

Model Discussion...
The numerical models are all fairly well-clustered with the
complex pattern over the next few days, but there are still fairly
notable differences with the way the models are handling the
energy moving east out of Siberia, and just how far east rainfall
makes it tonight and Tuesday. The ensemble members online, from
the 50 member ECMWF and the 30 member GFS are also in terrible
agreement, which depict large spreads of precip over the eastern
edge by Tuesday, with some models depicting 0.6 inches for
Fairbanks, and some showing none. Among the deterministic suite,
the NAM 12 00z was completely whiffing Fairbanks while the 06z NAM
shifted way east and now does bring rainfall to the area. GFS and
Canadian RGEM are in the middle, with the ECMWF 00z deterministic
most aggressive. Long story short, we will continue to favor a
"middle- ground" here given the uncertainty, which brings
widespread rainfall to the W Interior and Central Interior, with
likely rainfall chances moving into the Fairbanks area and W
Yukon Flats, and chances of rainfall further east. We will also
keep temps Tue a little lower, as clouds and rainfall early in the
day would obviously temper temps down.

Central and Eastern Interior...
Showers are coming back from the Minto Flats eastward Tuesday
afternoon. Temps moderate more this afternoon and will be a few
degrees warmer into the mid 60s. Rainfall is moving into the
Central Interior as early as late this evening, and shifting into
the western fringes of the E Interior from Fairbanks northward
into the Yukon Flats Tuesday morning. There will be a strong
cutoff in precip with no precip from Salcha east, and little to
nothing over the northern slopes of the Alaska Range. 0.5 to 1
inch of rainfall is expected from Tanana west, and northward to
the Dalton Highway corridor and Upper Koyukuk region. Fairbanks
will see a quarter of an inch to a tench of an inch of rainfall by
Tuesday afternoon.

Ridging aloft builds over the Interior Wednesday with much warmer
temps into the mid 70s, closer to the upper 70s over the SE
Interior, with increased chances for afternoon showers forming
over the higher terrain, along with isolated thunderstorm chances.

West Coast and Western Interior...
Some fog and stratus are plaguing the Lisburne Peninsula, but
that should continue to wane late this afternoon. A low from
Siberia will spread moderate and widespread rainfall across this
area this afternoon and evening, with rain spanning the entire
West Coast and Interior to the W Brooks Range by Tuesday morning.
Periods of rainfall will then continue all the way through
Wednesday morning before it begins to taper off late Wednesday
night, although it will likely persist through Thursday along the
SW Coast to Norton Sound. Expect widespread 0.75 to 1.75 inch
rainfall amounts by Thursday morning.

North Slope and Brooks Range...
Rain and snow showers taper off most areas this afternoon,
although a batch of stronger showers will develop over the E
Brooks Range this afternoon and evening. A low dropping into the
Chukchi Sea from the North Pole will quickly induce a strong
easterly gradient over the Arctic Tuesday morning through
Wednesday with easterly winds near gale force, and gusts to over
40 mph. Rain showers will clip the W Arctic mainly from Wainright
westward, with high pressure further east keeping things dry,
although stratus and fog will likely be lurking with a weak high
pressure over the Beaufort Sea.

Extended Forecast Days 4-7...
The global ensemble suite and the ensembles are all depicting a
565-568 dam closed blocking high aloft over the NE Interior on
Thursday, with a anomalously strong 532 dam low over the N Bering
Sea and the southwest coast however, instability is lower so it
looks like showers will be less numerous and weaker than they
were today, and southwest winds will also be 3 to 5 mph weaker
than they were today.of Alaska. South flow over the Alaska
Range will promote warmer temps over the E Interior (near
seasonal) with cooler temps out west, along with better shower
chances. Thursday through Saturday could be fairly warm over some
parts of the Yukon Flats and far E Interior, with some 80s
possible.

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

.FIRE WEATHER...
Heavy wetting rains move back into the West Coast and W Interior
later this afternoon, and will continue through Wednesday
morning, lasting longer over the West Coast. It looks to be pretty
wet with 0.75 to 1.75 inches by Thu morning. Further east, those
wetting rains will get close to Fairbanks, with a 50/50 chance
they make it there, but it will be a sharp line with much heavier
rainfall north and west across the Central Interior and into the
White Mtns. The Alaska Range looks to only get clipped with low
chances for wetting rains except over the far western parts. The
Yukon Flats has a low chance for wetting rains, with dry
conditions generally expected from Salcha east with the next rain
event tonight through Tuesday night.

Prior to that, this afternoon will be a few degrees warmer with
continued shower chances, albeit much lower in coverage and
intensity. After the aforementioned rainfall Tuesday, it will be
warming quite a bit Wednesday with temps shooting into the mid to
upper 70s Wednesday, with a slight chance of thunderstorms
relegated to the SE Interior. Minimum RHs by Wednesday are back
down into the 30 % range in the valleys and 40 % range over higher
elevations.

There will be south gap winds of 30 to 40 mph through the AK Range
Monday night through Tuesday evening.

.HYDROLOGY...
More rainfall out west of 0.75 to 1.75 inches through Thursday
will be fairly spread out, so while it is a lot of rainfall, no
significant issues are anticipated as rivers are running a little
higher, but not high. Faster streams will definitely see more
rises so locals should remain vigilant.

The Sag crested at Pump Station 3 at action stage, so that water
should be moving downstream the next couple days, but no flooding
is expected.

The Tanana River continues it summer rise as glacial melt and
high elevation snowmelt continues feeding it, with it rising to
near action stage at Fairbanks by Wednesday or Thursday.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...None.
PK...Brisk Wind Advisory for PKZ813-859.
     Brisk Wind Advisory for PKZ814-815-860-861.
&&

$$

GJM