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000
FXAK68 PAFC 021350
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
450 AM AKST Tue Mar 2 2021

.ANALYSIS AND UPPER LEVELS...

Satellite imagery shows a weakening vertically stacked, complex
low residing over the eastern Bering this morning, keeping the an
active pattern stretched across the region. On the backside of
this system, strong winds persists from the Pribilofs to the
eastern Aleutians and AKPEN, which has dropped the visibility at
times during periods of light snow. Over the Southwest mainland,
snow showers continue as the front with the aforementioned low
pushes farther inland. Snow has already started to taper off over
the Kuskokwim Delta and will continue to weaken from west to east.
Across Southcentral, a compact low is lifting into the North Gulf
Coast. Relatively quiet conditions remain across the region as
the northerly offshore pattern begins to set up.

&&

.MODEL DISCUSSION...

Models remain in good consensus with the active weather pattern
across the Bering and mainland Alaska over the next few days.
Thus, forecast confidence remains above average.

&&

.AVIATION...

PANC...MVFR conditions are possible early this morning, which will
gradually improve to VFR with light winds by the afternoon. Fog
and low stratus could develop Tuesday evening across Cook Inlet
and at the airport.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2: Today
through Wednesday Night)...

For most of Southcentral, the weather will be much quieter today,
and the quiet weather will persist through Wednesday night. Light
snow continues this morning in Cordova and points east, as the low
that greatly assisted in causing the snow area-wide yesterday
moves into the coastal Chugach and rapidly dissipates. Lingering
moisture may cause light snow shower activity to persist
throughout the day today in the Cordova area. Elsewhere, low cloud
cover is over much of Southcentral, however, most of it is not
producing precipitation. The cloud cover should slowly diminish
through today with solar heating.

The weak surface low/troughing over Southwest Alaska will shift
east and consolidate into a low over the eastern Gulf by Wednesday
morning. This will allow a renewed surge of Arctic air to move
southward across Southcentral by Wednesday. In addition to falling
temperatures, the most significant impact will be strengthening
winds and freezing spray potential across all of the coastal
waters north of Kodiak Island by Wednesday night. This surge of
colder, drier air should result in continued dissipation of any
remaining cloud cover. However, the resulting atmospheric
inversion may support some limited freezing fog generation,
especially in the upper Cook Inlet and the Arms. Even in these
areas, the fog tonight is not expected to be dense due to the
otherwise dry air mass around.

Looking ahead, the next round of inland and mountain snow with
coastal rain/mix remains on track starting Thursday night, and
may persist into Saturday. This feature is looking more
substantial as compared with 24 hours ago, but the details that
will determine how much accumulation occurs remain highly
uncertain.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 2)...

A broad surface low in the eastern Bering will continue to
influence the sensible weather across Southwest Alaska today.
Remnant moisture embedded in cyclonic flow will produce more
showers today for portions of Southwest Alaska. As the low pushes
south today, northerly flow will set up for most of the region.
There will be a break between systems on Wednesday. Thursday the
next Bering front will push inland bringing yet another batch of
snow to the K-Delta, Bethel, Dillingham and King Salmon.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 2)...

The remnants of a low over the Bering continues to yield snow
showers, gusty conditions, and enhanced seas. The surface low
will move out of the Eastern Bering and south of the Alaska
Peninsula this afternoon. In its wake, northerly flow and a tight
pressure gradient from the Pribilof Islands to Port Heiden. By
Wednesday morning there will be a weak ridge over Atka and St.
Paul. Additionally, there is a new surface low over Kamchatka with
a surface pressure of 967 mb and the front at the door set of
Attu Island. This front will rapidly push across the Aleutians
Wednesday and early Thursday bringing another round of unsettled
weather.

&&

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

Bering: A well developed front moves into Western Alaska for Fri.
Forecast confidence is good. Widespread high end southerly gale
force winds and waves with areas of storm force gusts moves with
the front. Waves building to 20 feet Fri. The associated well
developed low and trailing front move across the Bering from the
West through Fri, and brings widespread high end westerly gale
force winds across the Aleutians/Bering through Sat. Waves
building to 35 feet over the Central Bering subsiding to mid-20s
over the remainder of the area through Sat.

Gulf of Alaska: A low slowly exits the Southern Gulf Fri, with
outflow small craft winds off the Alaska Peninsula from the Barren
Islands to the Shumagin Islands right behind. Models vary, but
confidence is good. A new low and front move across the Gulf
through Sat, bringing widespread southeasterly winds with the
front through Fri. Northwest small craft winds with areas if gale
force gusts follow after frontal passage Sat. Waves building to 12
feet across the Southern Gulf, subsiding Sat.

&&

.LONG TERM FORECAST (Days 4 through 7: Friday through Monday)...

Active weather is expected to makes its return to southern Alaska
during the forecast period with the details of each individual
system uncertain at this time. Model guidance keeps a rather
strong Arctic/Siberian upper level low over northeast Russia while
upper level ridging tries to push northward along the Alaska
Peninsula into Southcentral and Southeast Alaska. The storm track
will basically be from the western Bering eastward along the
Aleutian Chain to Kodiak Island and then to somewhere near Prince
William Sound as these ride the eastern periphery of the deep cold
Arctic/Siberian air over northeast Russia. Overall, expect a
milder pattern to ensue for this time period with temperatures
still slightly below normal but closer to the normal values of
where they typically are this time of the year which is near 32
degrees F for Anchorage. This pattern could potentially mean a
snowier regime for Southcentral and in particular across the
Anchorage Bowl. However, many factors have to come together for
Anchorage to get the snow, though, the storm track looks favorable
with model guidance mostly bringing lows near and into Prince
William Sound with details of each uncertain.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Blizzard Warning 185 195
         Winter Weather Advisory 155 181
         High Wind Warning 185
MARINE...Storm Warning 170 178 411
         Gales 130 131 150 155 160 165 171-77
               179 180 185 412 413 414
         Heavy Freezing Spray 160 165 179 180 185 412 414
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...ALH
SOUTHCENTRAL ALASKA...JPW
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PJS
MARINE/LONG TERM...MK/MV