358
FXAK69 PAFG 081001
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
201 AM 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 today.
Rain will move into the Interior as far east as the Fairbanks
area Monday night and Tuesday morning before it begins warming
back to seasonal norms (mid 70s) by Wednesday.

&&

.DISCUSSION...

Upper Levels and Analysis...
A strong and anomalous for this time of year upper level low is
centered over the Arctic coast with heights around 535 dam. The
main center is currently over Umiat, with a basal shortwave trough
moving into the Yukon Flats this morning. There is a shortwave
trough over E Siberia with heights around 556 dam, with the
leading edge front moving into the Bering Strait this morning.
There is a vigorous 535 dam arctic "bowling ball" low quickly
diving south from the North Pole. There is a 544 dam low centered
over the S Gulf of Alaska with a fairly spiraliform looking
marine occlusion on satellite. The main surface low is a weak 1011
mb low over the Yukon Flats, with a 1015 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 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 on Monday night 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
definitely 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 tapering off slightly this morning, but then will come
back from the Minto Flats eastward tomorrow afternoon. 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. Temps
moderate more today 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 slops 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 Chukchi Coast, but that
should wane this afternoon. A low from Siberia will spread
moderate and widespread rainfall across Norton Sound this morning
and that spreads inland through the 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
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 by later today,
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 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 535 dam low over the N Bering
Sea and the southwest coast 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 today, 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, today will be a few degrees warmer with continued
shower chances, albeit much lower on coverage and lighter. 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...None.

&&

$$

Ahsenmacher