Brisk Wind Advisory 51, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
549 AM AKST Tue Feb 22 2022

.ANALYSIS AND UPPER LEVELS...

A broad longwave trough exists from the Kamchatka Peninsula to the
Central Aleutians with a high amplitude ridge extending from the
northern tropics north to southern Alaska before sharply dropping
south along the West Coast of North America. A shortwave trough
embedded at the top of the ridge axis is driving east across
Southcentral this morning, providing active weather to the region.
Overnight, this shortwave has produced widespread precipitation
across most of southcentral with a wide variety of precipitation
types observed. The back edge of the precipitation can be seen
rapidly coming to an end on the Middleton Island and Kenai Radars
with clearing observed in satellite imagery behind the departing
front. Out west, a large low pressure system exists southwest of
Shemya with it's front sweeping east along the Aleutian Chain.
Another deep system in the north-central Pacific can be seen on
Satellite, and will be a factor as it moves slowly north and
merges with the trough to the west.

&&

.MODEL DISCUSSION...

Overall synoptic scale model agreement is good with the shortwave
departing east into the Alaska Panhandle and British Columbia
later today. Agreement deteriorates rapidly by Wednesday afternoon
as multiple shortwaves round around the trough axis and move
north into southern Alaska. This will cause some minor differences
in the timing of precipitation, but the overall effect on the
forecast should be minimal.

&&

.AVIATION...
PANC...Gusty southeasterly winds will slowly taper off this
morning and become southerly. Snow and rain should end around to
just after sunrise with an accompanying rise in ceilings and
visibility out of MVFR conditions. Fog is not expected at this
time with drier air moving in after frontal passage. Light
northerly winds will become predominant tonight.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Today through Thursday
Night)...

The strong winter storm that has been impacting the area over the
past 24 hours is departing Southcentral. For more details on the
impacts and highlights, see the Public Information Statement.

Inland snow or a rain/snow mix along the coast associated with
this storm will gradually taper off today around Prince William
Sound and all of the various mountain ranges around the area.
Tonight, we will have a brief break in the weather, that is likely
to include at least partial clearing. The clearing skies will be
simultaneous with diminishing winds. While the break in the cloud
cover will be brief with high clouds ahead of the next system
already moving in Wednesday morning, the combination of clear
skies and calm or nearly calm winds tonight will allow for the
temperatures to fall well below freezing. Thus, patchy slick areas
are likely to develop across much of the region by the Wednesday
morning commute.

The tail end of the front associated with today's departing storm
will make another run at Southcentral. Rain will break out in
Kodiak this evening. However, unlike today, by tonight the flow in
the upper levels will be southeasterly. Thus, that moisture will
move northwest into Southwest Alaska, and mostly bypass much of
Southcentral. The one exception is Kodiak, which could pick up
anywhere from three quarters of an inch to 1.5 inches of rain by
Thursday. The upper level southeasterly flow will also allow the
precipitation to creep up the coast on Wednesday, resulting in
another round of coastal rain, mountain snow, and a valley mix by
Wednesday evening. The Turnagain Arm wind will also redevelop
during the day Wednesday and persist straight through Thursday
night and beyond. However, unlike the current system, this time
the wind will stay aimed west or southwest, and is not expected to
directly impact Anchorage. Northerly flow through this event
should help to keep the area cooler. Another way this will be
different is the upslope/downslope couplet will definitely be
present. This will keep almost all of the western Kenai Peninsula,
Anchorage, and points north dry.

A series of waves, each one stronger than the previous will track
northwestward over or near Kodiak Island through Thursday night.
While this means the island will see almost non-stop rain once it
begins tonight right through Thursday night, this also means there
will be relatively little activity going over much of
Southcentral, so the support for precipitation from Anchorage
north will not be present until this weekend, when the flow will
turn southerly enough to increase precipitation chances. The
southeasterly flow will keep conditions mainly cloudy through the
end of the week, and also prevent any cold air from returning, so
expect continued above average temperatures, with highs most days
getting well above freezing. Thus, slow melting of the snowpack
will continue.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 to 2 - Today through
Wednesday night)...

A potent upper level shortwave responsible for the mix of rain and
snow across much of the region on Monday has now lifted northeast
into the central interior, with low stratus, weak southwest winds
and temperatures hovering right around freezing in place behind
the departing system. Another wave will move swiftly across the
Kuskokwim Delta this morning with another brief round of light snow
mixing with rain to the area, with a slushy half-inch or less of
new accumulation possible before precipitation shuts off this
afternoon.

By tonight, a large and complex low swirling over the Bering will
send a front across the Alaska  as a longwave ridge takes shape
once again over much of the AK mainland to the east. A tightening
pressure gradient between these two synoptic features will drive
southeast winds that will increase into Wednesday, especially
across parts of Bristol Bay. A significant surge of warm and moist
advection ahead of the front should push low level temperatures
well above freezing, with highs reaching into the upper 30s to low
40s on Wednesday. The robust southeast flow should keep most
precipitation associated with the frontal system confined to areas
favoring upslope flow, namely along the Kuskokwim Mountains and
on lee faces of the Alaska and Aleutian Ranges. Conversely, nearly
everywhere else (aside from the Kuskokwim Delta Coast) will stay
dry due to downslope flow off of the same terrain features.
Temperatures will be warm enough for anything that does fall away
from the mountains to reach the ground as all rain through
Wednesday evening. Gusty southeast winds will continue well into
Wednesday night, particularly where funneled through the Kamishak
Gap into Bristol Bay. Easterly gusts of 50 to 60 mph will be
possible along a corridor roughly from Iliamna to Koliganek with
these winds Wednesday afternoon and evening.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 to 2 - Today
through Wednesday night)...

A gale force front spiraling out from a massive, complex low will
advance from the central Aleutians to the southern Alaska
Peninsula by Wednesday morning, sending periods of mainly rain
across the central and eastern Aleutians as series of smaller
waves/lows move north along the boundary. Farther west, the parent
low will slowly drift into the western Aleutians through
Wednesday. Cooler air aloft near the low center will support weak
marine layer instability and convective rain/snow showers
wrapping around the low and across the western Aleutians through
Wednesday evening. The aforementioned frontal system will send
periods of rain and developing small craft southeast winds across
the Pribilofs beginning this evening, with occasional mixing with
snow possible with heavier bands of precipitation moving across
through Wednesday afternoon.

&&

.Marine (Days 3 through 5: Thursday through Saturday)...

Gulf of Alaska:
A barrier jet is expected to set up along the Gulf coast
beginning Wednesday night that will strengthen to gales and
possibly storm force through at least Friday as a low enters the
Gulf on Thursday and tracks north. As this low moves inland,
westerly winds will return and diminish the coastal barrier jet
Saturday. Seas build through late Friday night to around 20 feet,
but expect seas to go back down to around 10 feet Saturday night.

Bering Sea/Aleutians:
A passing low northward across the Aleutians and the Bering sea
will keep southerly flow across the region through Friday when
winds will become westerly and another low approaches from the
western Gulf toward the AKPen. Winds will return to generally
southerly flow again Saturday. Seas to about 10 feet on the Bering
side and generally 10 to 15 feet on the Pacific side through the
last half of the week.

&&

.Long Term Discussion (Days 4 through 7: Friday through Monday)...

Overall, the latest operational model runs are in decent agreement
with the synoptic scale features in the short term, but increasing
uncertainty emerges toward the end of the period. A large upper
level ridge extends northwestward from the eastern Pacific into
the Arctic. Meanwhile, a negatively-tilted trough extends from the
western to central Bering Sea to the central Pacific. This synoptic
setup will set the stage for a southerly flow pattern to persist
possibly through early next week.

On Friday, models are suggesting a shortwave and developing
surface low south of the Alaska Peninsula/Kodiak Island streaming
northward into the Gulf. With southerly flow and warmer air aloft,
most of the precipitation will fall as rain along the southern
Alaska coast and parts of the interior valleys. The exception will
be for the surrounding mountains as precipitation type is
expected to be snow as colder air remains in place. However,
moisture may be limited in the Western Kenai Peninsula, Anchorage,
and the Matanuska Valley as 850 mb winds shows a southeasterly
component flowing across the Chugach Mountains, which would result
in downslope drying.

Out west, broad cyclonic flow with embedded shortwaves will
maintain a cool and wet pattern for the Bering Sea and Aleutian
Islands through the end of the weekend. However, model spread has
increased significantly with the small to mid scale embedded
systems streaming northward from the southern Bering Sea, though
minimal impact is expected. By early Monday, a gale force front
extending from a Kamchatka low will move slowly east across the
Western/Central Aleutians.

&&
.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Storm Warning: 145.
MARINE...Gale Warning: 119,125,130,131,138,139,160,165,170,
173-176,180-185.
FIRE WEATHER...NONE.

&&

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

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1008 AM AKST TUE FEB 22 2022

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

0800 AM     HEAVY SNOW       4 SW TRAPPER CREEK      62.19N 150.50W
02/22/2022  E12.0 INCH       MATANUSKA-SUSITNA  AK   CO-OP OBSERVER

            12-HR PCPN. STORM TOTAL 17.8 INCHES.

1001 AM     HEAVY SNOW       24 N CHASE              62.79N 150.00W
02/22/2022  E24.0 INCH       MATANUSKA-SUSITNA  AK   DEPT OF HIGHWAYS

            LITTLE COAL CREEK TO TALKEETNA TURNOFF.

1004 AM     HEAVY SNOW       1 SSW TALKEETNA         62.32N 150.11W
02/22/2022  E18.0 INCH       MATANUSKA-SUSITNA  AK   DEPT OF HIGHWAYS

            ALONG TALKEETNA TURNOFF.

1007 AM     SNOW             1 SE WILLOW             61.73N 150.03W
02/22/2022  E6.0 INCH        MATANUSKA-SUSITNA  AK   DEPT OF HIGHWAYS

0955 AM     HEAVY SNOW       1 NNE CANTWELL          63.39N 148.90W
02/22/2022  E14.0 INCH       DENALI             AK   DEPT OF HIGHWAYS

            DENALI PARK TO LITTLE COAL CREEK.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1012 AM AKST TUE FEB 22 2022

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

0635 PM     SNOW             4 WNW PALMER            61.62N 149.21W
02/21/2022  M7.1 INCH        MATANUSKA-SUSITNA  AK   NWS EMPLOYEE

            NEAR THE INTERSECTION OF CHURCH ROAD AND
            PITTMAN ROAD.

0700 PM     SNOW             4 SSW MEADOW LAKES      61.58N 149.65W
02/21/2022  U6.5 INCH        MATANUSKA-SUSITNA  AK   PUBLIC

0925 PM     SNOW             4 NNW WASILLA           61.63N 149.49W
02/21/2022  M9.2 INCH        MATANUSKA-SUSITNA  AK   PUBLIC

            NEAR THE INTERSECTION OF CHURCH ROAD AND
            PITTMAN ROAD.

0800 AM     HEAVY SNOW       4 SW TRAPPER CREEK      62.19N 150.50W
02/22/2022  E12.0 INCH       MATANUSKA-SUSITNA  AK   CO-OP OBSERVER

            12-HR PCPN. STORM TOTAL 17.8 INCHES.

1001 AM     HEAVY SNOW       24 N CHASE              62.79N 150.00W
02/22/2022  E24.0 INCH       MATANUSKA-SUSITNA  AK   DEPT OF HIGHWAYS

            LITTLE COAL CREEK TO TALKEETNA TURNOFF.

1004 AM     HEAVY SNOW       1 SSW TALKEETNA         62.32N 150.11W
02/22/2022  E18.0 INCH       MATANUSKA-SUSITNA  AK   DEPT OF HIGHWAYS

            ALONG TALKEETNA TURNOFF.

1007 AM     SNOW             1 SE WILLOW             61.73N 150.03W
02/22/2022  E6.0 INCH        MATANUSKA-SUSITNA  AK   DEPT OF HIGHWAYS

0415 PM     SNOW             1 SE NIKISKI            60.69N 151.29W
02/21/2022  M5.0 INCH        KENAI PENINSULA    AK   TRAINED SPOTTER

            MILE 24 KENAI SPUR ROAD: 5 INCHES.

0955 AM     HEAVY SNOW       1 NNE CANTWELL          63.39N 148.90W
02/22/2022  E14.0 INCH       DENALI             AK   DEPT OF HIGHWAYS

            DENALI PARK TO LITTLE COAL CREEK.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1150 AM AKST TUE FEB 22 2022

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

0915 PM     NON-TSTM WND GST 11 SE ANCHORAGE         61.10N 149.69W
02/21/2022  E61 MPH          ANCHORAGE          AK   CO-OP OBSERVER

0953 PM     NON-TSTM WND GST 3 SW ANCHORAGE          61.18N 149.96W
02/21/2022  E44 MPH          ANCHORAGE          AK   ASOS

0953 PM     NON-TSTM WND GST 10 SE ANCHORAGE         61.10N 149.72W
02/21/2022  E44 MPH          ANCHORAGE          AK   ASOS

1200 AM     NON-TSTM WND GST 9 SE ANCHORAGE          61.11N 149.74W
02/22/2022  E81 MPH          ANCHORAGE          AK   NWS EMPLOYEE

1200 AM     NON-TSTM WND GST 15 W WHITTIER           60.76N 149.18W
02/22/2022  E72 MPH          KENAI PENINSULA    AK   CO-OP OBSERVER

1230 AM     NON-TSTM WND GST 8 S ANCHORAGE           61.10N 149.85W
02/22/2022  E66 MPH          ANCHORAGE          AK   CO-OP OBSERVER

1230 AM     NON-TSTM WND GST 9 SE ANCHORAGE          61.12N 149.72W
02/22/2022  E67 MPH          ANCHORAGE          AK   CO-OP OBSERVER

1252 AM     NON-TSTM WND GST 1 SE PALMER             61.59N 149.09W
02/22/2022  E59 MPH          MATANUSKA-SUSITNA  AK   PUBLIC

0100 AM     NON-TSTM WND GST 17 NW WHITTIER          60.95N 149.09W
02/22/2022  E66 MPH          ANCHORAGE          AK   CO-OP OBSERVER

0107 AM     NON-TSTM WND GST 4 W WHITTIER            60.78N 148.84W
02/22/2022  E62 MPH          ANCHORAGE          AK   ASOS

0231 AM     NON-TSTM WND GST 5 SW ANCHORAGE          61.17N 150.00W
02/22/2022  E44 MPH          ANCHORAGE          AK   ASOS

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1154 AM AKST TUE FEB 22 2022

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

0915 PM     NON-TSTM WND GST 11 SE ANCHORAGE         61.10N 149.69W
02/21/2022  E61 MPH          ANCHORAGE          AK   CO-OP OBSERVER

0953 PM     NON-TSTM WND GST 10 SE ANCHORAGE         61.10N 149.72W
02/21/2022  E44 MPH          ANCHORAGE          AK   ASOS

0953 PM     NON-TSTM WND GST 3 SW ANCHORAGE          61.18N 149.96W
02/21/2022  E44 MPH          ANCHORAGE          AK   ASOS

1200 AM     NON-TSTM WND GST 15 W WHITTIER           60.76N 149.18W
02/22/2022  E72 MPH          KENAI PENINSULA    AK   CO-OP OBSERVER

1200 AM     NON-TSTM WND GST 9 SE ANCHORAGE          61.11N 149.74W
02/22/2022  E81 MPH          ANCHORAGE          AK   NWS EMPLOYEE

1230 AM     NON-TSTM WND GST 9 SE ANCHORAGE          61.12N 149.72W
02/22/2022  E67 MPH          ANCHORAGE          AK   CO-OP OBSERVER

1230 AM     NON-TSTM WND GST 8 S ANCHORAGE           61.10N 149.85W
02/22/2022  E66 MPH          ANCHORAGE          AK   CO-OP OBSERVER

1252 AM     NON-TSTM WND GST 1 SE PALMER             61.59N 149.09W
02/22/2022  E59 MPH          MATANUSKA-SUSITNA  AK   PUBLIC

0100 AM     NON-TSTM WND GST 17 NW WHITTIER          60.95N 149.09W
02/22/2022  E66 MPH          ANCHORAGE          AK   CO-OP OBSERVER

0107 AM     NON-TSTM WND GST 4 W WHITTIER            60.78N 148.84W
02/22/2022  E62 MPH          ANCHORAGE          AK   ASOS

0231 AM     NON-TSTM WND GST 5 SW ANCHORAGE          61.17N 150.00W
02/22/2022  E44 MPH          ANCHORAGE          AK   ASOS

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1247 PM AKST TUE FEB 22 2022

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

0845 PM     NON-TSTM WND DMG 3 ESE PALMER            61.59N 149.03W
02/21/2022                   MATANUSKA-SUSITNA  AK   PUBLIC

            PUBLIC REPORTS POWER OUTAGES WITH TREE IN
            THE POWER LINES.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1248 PM AKST TUE FEB 22 2022

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

1119 AM     NON-TSTM WND GST 11 SE ANCHORAGE         61.10N 149.69W
02/22/2022  E61 MPH          ANCHORAGE          AK   CO-OP OBSERVER

1120 AM     NON-TSTM WND GST 9 SE ANCHORAGE          61.12N 149.72W
02/22/2022  E67 MPH          ANCHORAGE          AK   CO-OP OBSERVER

&&