Area Forecast Discussion
Issued by NWS Anchorage, AK

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000
FXAK68 PAFC 221252
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
452 AM AKDT Sat Jul 22 2017

.ANALYSIS AND UPPER LEVELS...
A fairly tranquil pattern remains in place across the region this
morning as a stout ridge over the Bering Sea continues to extend
eastward over mainland Alaska. This is yielding mostly clear
skies over the southern mainland, although cloud cover is a
little more extensive across the Greater Bristol Bay region owing
to weak shower activity associated with a shortwave that passed
through the area last evening. Widespread fog and stratus remain
locked in place across the Bering and Aleutians beneath the
dominant high pressure.

&&

.MODEL DISCUSSION...
Models remain in strong synoptic agreement into the beginning of
the week as the ridge flattens out and gives way to zonal flow
across the Bering Sea and mainland Alaska. Continued to primarily
utilize Hi-Res NAM guidance for the morning forecast package to
better depict local influences.

&&

.AVIATION...
PANC...VFR conditions and light winds will persist, with light inlet
breezes once again developing in the afternoon.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...

An upper level ridge continues to drive clearing and drying
conditions across much of Southcentral, with noctilucent clouds
clearly visible in the skies early this morning. This ridge will
continue to support mostly clear skies and warmer temperatures
across Southcentral today as it pushes farther eastward. Some
clouds may form along the Alaska Range and Talkeetna Mountains by
the afternoon, but conditions are generally too stable to support
any showers.

More unstable weather will begin Sunday evening, as an upper level
wave progresses rapidly from the west to east across Southcentral.
Rain is expected to occur mainly in the northern Susitna Valley
and northern Copper River Basin. Currently steady rain is not
expected in the Anchorage Bowl or Matanuska Valley, but there
will be enough forcing for some scattered showers along the
Chugach Mountains Sunday night into Monday. &&

.SHORT TERM FORECAST SOUTHWEST ALASKA...
High pressure will remain over southwest Alaska through tonight
before a front moves in from the northwest. The front will bring
rain to the region beginning with the Kuskokwim Delta and
spreading east through Sunday making it across all of southwest
Alaska Sunday night. On Monday, lighter rain will persist behind
the front and max temps will drop back into the 60s from the
warmer previous couple of days.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS...
High pressure remains in place for much of the Bering and
Aleutians keeping stratus and fog widespread over these areas.
However, a front has begun to ride over top of the ridging moving
into the western Bering. It will push through the northern Bering
on Saturday and make it to the west coast by Sunday with the rest
of the front draped across the Pribilof Islands and the southern
Bering. It will then slowly track east arriving to the Eastern
Aleutians and Alaska Peninsula on Monday.

&&

.LONG TERM FORECAST (Days 3 through 7)...

The long range forecast will be in a progressive pattern as an
upper low over the Arctic sends several shortwaves to the southern
mainland. Under this regime, occasional showers are expected
Monday night through Friday across the southern mainland and the
Gulf of Alaska. To the west, a ridge takes residence along the
western half of the Aleutians keeping much of the Bering dry,
however low clouds and fog will persist under the stable air mass.
The central and eastern Bering will mainly be influenced by the
upper low. Models are in relatively good agreement with the
synoptic pattern through the extended timeframe, therefore a blend
of the operational models and their ensembles were used to update
the latest package.


&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE
MARINE...NONE
FIRE WEATHER...NONE

&&

$$

SYNOPSIS AND MODEL DISCUSSION...CB
AVIATION...CB
SOUTHCENTRAL ALASKA...ELN
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...DK
LONG TERM...KH



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