Small Craft Advisory 41, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
442 PM AKST Sat Jan 15 2022

.ANALYSIS AND UPPER LEVELS...

The weather feature causing widespread precipitation (mostly in
the form of snow for much of Southern Alaska), is relatively weak
and the snow has been light so far. An upper level low is
currently over the Lower Kuskokwim Valley. Since the leading edge
of the upper level energy is currently moving northeast across
Southcentral, that puts much of Southcentral in a region of
atmospheric lift, which is what is causing the wintry weather we
are seeing.

In the upper levels, the upper low over Southwest Alaska continues
to move northeast. Weak westerly jet streaks are over the eastern
Bering, and a second southerly jet streak is approaching the
Central and Western Aleutians ahead of a second separate upper
level low.

&&

.MODEL DISCUSSION...

The models remain in excellent agreement on the large scaled
through Monday afternoon. The greatest forecast uncertainties are
actually in the very near-term, determining snowfall timing and
intensity across Southcentral as the aforementioned area of lift
and moisture continue to move northward across the area. With
overall quiet weather to follow for much of southern mainland
Alaska, and a typical large but well-agreed-upon low over the
Bering, forecast confidence is high.

&&

.AVIATION...
PANC...MVFR and IFR conditions are expected into the evening
hours as an area of snow lifts across the area. Once the
precipitation has ended, lingering lower cloud cover could keep
ceilings at MVFR for several hours into tonight, followed by off-
and-on VFR and MVFR ceilings with unlimited visibility. Any fog
redevelopment tonight will be patchy at most due to steady
southerly winds up the Inlet mixing the fog out through the lower
atmosphere. The winds will relax by Sunday morning.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3:
Saturday night through Tuesday)...

A large upper low is moving slowly east across Southcentral this
evening, bringing a moderately heavy band of snow across most of
the region. Accumulations may stack up for a quick 2 to 4 inches
from Anchorage into the Mat-Su and north to Talkeetna. The return
of colder air aloft can be seen well on radar as the sharp end in
reflectivity currently over the Kenai Peninsula. Mountain areas
could see an additional 3 to 6 overnight. Valdez will also receive
an additional 3-6 inches tonight with maybe some flurries
lingering into tomorrow morning.

By Sunday afternoon the trough will depart and elongate as it
moves through the Panhandle and into British Columbia. It will be
replaced by a shortwave ridge, which will provide a nice break in
the weather for all of Southcentral. Some low stratus may linger
through the cook inlet and along the coast, but the sun should
break through a few times early next weak. Expect temperatures to
be around average to slightly above average.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3: Tonight
through Tuesday)...

A combination of steady light snow and freezing fog continue to
stream across portions of Bristol Bay and Kuskokwim Delta, from
Nushagak Peninsula to the south of Quinhagak from cloud bands
moving onshore this afternoon. The upper low over Southwest is
slowly approaching the lower Kuskokwim Valley while steady light
snow continues across Sleetmute and Lime Village into this
afternoon. The potential for isolated to scattered snow showers is
favorable for much of Southwest Alaska as the upper low continues
to expand while forcing its way into Southcentral overnight
tonight. For this event, additional snowfall will continue over
the lower Kusko Valley and parts of Kuskokwim Delta, and farther
inland of Bristol Bay area. Following this current event, another
series of considerable snow amounts should arrive by Sun night as
multiple waves aloft combined with a frontal system over the
Bering pushes eastward through the Southwest Coast through Tue.
Essentially, wintry conditions will remain in the forecast with a
brief break from snow between Sun morning and Sun afternoon
reflecting the west to east motion of an upper ridging through the
region.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3:
Tonight through Tuesday)...

A broad frontal system latched to a North Pacific low will remain
as the top weather driver for the Bering/Aleutians through the
short term. Gales and gusts reaching storm-force have made their
way through Shemya and parts of the western Aleutians this
afternoon, and this pattern should continue as the front curves
north-northwest into Sun evening placing gales north of the
Aleutians by Sun afternoon. Solutions indicated the potential for
this front to remain nearly stationary over the western tip of
off-shore waters and just west of Shemya through Mon night. A new
North Pacific low races through the western Aleutians between Mon
night and Tue morning, which could elevate winds and seas across
the most western area of the Aleutians Tue and Tue night. For now,
will continue monitoring this situation and provide updates. Stay
tuned! Heavy freezing spray continues over the Northern Bering.

&&

.MARINE (Days 3 through 5 - Tuesday through Thursday)...

Gulf of Alaska...High pressure moves onshore over Southeast
Alaska for Wednesday. A well developed low enters the Western Gulf
Wednesday and moves to the North Gulf Coast by Thursday. Its
front extends across the Gulf through Thursday. Forecast
confidence is good. Gusty winds spreads over the Gulf, increasing
to Easterly gales Wednesday, diminishing Thursday. Seas build to
15 feet Wednesday, subsiding Thursday.

Aleutians / Bering...A well developed low South of Amchitka
retrogresses South of Kamchatka for Thursday. Forecast confidence
is mixed with the low's movement. Broad low pressure remains in
place South of the Aleutians and Alaska Peninsula through
Thursday. Arctic high pressure holds over the Russian Far East.
Widespread gales extend across the Central and Western Aleutians
and Bering. Seas to 22 feet, subsiding from East to West by
Thursday.

&&

.LONG TERM FORECAST (Days 4 through 7: Wednesday through
Saturday)...

Latest model guidance is in reasonable agreement with the
evolution and progression of synoptic scale features into early
next week. However, models begin to diverge significantly with the
specific details towards the end of the period. For most of the
southern mainland, high pressure will give way to a brief period
of dry weather and seasonal temperatures before a wet pattern
returns Wednesday and onward. There is decent consistency for a
North Pacific low tracking south of the Alaska Peninsula into or
near the Gulf, with another low following closely behind later
next week. Models are keying in on a frontal boundary extending
from the center of the first North Pacific low, which will bring
some warmer air, precipitation, and wind from Kodiak Island
northward to the southern mainland. If this scenario materializes,
there is a potential that a barrier jet may develop along the
northern Gulf coast from Prince William Sound to the Copper River
Delta area. Uncertainty emerges in the track, position, and timing
of these systems. The GFS continues to be the wettest compared to
the other drier solutions. Out west, a broad trough will settle
just south of the Aleutians while weak, embedded shortwaves pivot
around the eastern periphery of the aforementioned trough. This
will bring a wintry mix of rain/snow and gusty winds along the
southern portion of the Aleutians and into the Bering Sea.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 170 172-177 185. Storm 178.
		 Heavy Freezing Spray 185.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...JPW
SOUTHCENTRAL ALASKA...CJ
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CB
MARINE/LONG TERM...MK/MF

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1020 PM AKST SAT JAN 15 2022

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1006 PM     SNOW             4 NW WASILLA            61.63N 149.48W
01/15/2022  M4.8 INCH        MATANUSKA-SUSITNA  AK   PUBLIC

1102 AM     SNOW             4 W STERLING            60.51N 150.91W
01/15/2022  M1.2 INCH        KENAI PENINSULA    AK   PUBLIC

0558 PM     SNOW             9 SE ANCHORAGE          61.12N 149.72W
01/15/2022  M4.5 INCH        ANCHORAGE          AK   PUBLIC

0715 PM     SNOW             8 SE ANCHORAGE          61.11N 149.78W
01/15/2022  M3.4 INCH        ANCHORAGE          AK   PUBLIC

0837 PM     SNOW             9 SE ANCHORAGE          61.12N 149.72W
01/15/2022  M7.5 INCH        ANCHORAGE          AK   PUBLIC

0943 PM     SNOW             11 SE KNIK              61.32N 149.54W
01/15/2022  M6.5 INCH        ANCHORAGE          AK   PUBLIC

1019 PM     SNOW             11 SSE ANCHORAGE        61.07N 149.72W
01/15/2022  E5.5 INCH        ANCHORAGE          AK   NWS EMPLOYEE

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1023 PM AKST SAT JAN 15 2022

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0658 PM     SNOW             11 SSE ANCHORAGE        61.07N 149.77W
01/15/2022  M3.5 INCH        ANCHORAGE          AK   PUBLIC

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1027 PM AKST SAT JAN 15 2022

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1000 PM     SNOW             EAGLE RIVER             61.31N 149.56W
01/15/2022  E5.0 INCH        ANCHORAGE          AK   PUBLIC

            TEMP: 28 SNOW AND BLOWING SNOW 1/2 MILE
            VISIBILITY.

&&

RC