Area Forecast Discussion
Issued by NWS Anchorage, AK

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000
FXAK68 PAFC 170048
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
448 PM AKDT Sat Jun 16 2018

.ANALYSIS AND UPPER LEVELS...
The broad remnants of Tropical Storm Maliksi continue to dominate
the weather throughout the South Mainland into the Eastern Bering
with widespread rains and gusty winds. A widespread band of
precip moved through Southcentral and the Kuskokwim Delta earlier
this morning, but was followed by a brief break for the
afternoon. This however is quickly beginning to fill in as
showers are redeveloping over Southern Cook Inlet into Bristol Bay
and spreading northward in response to an incoming shortwave.
Widespread fog and stratus has developed over much of the Gulf of
Alaska under the persistent and moist southerly flow, which will
likely continue into Sunday as weak high pressure develops ahead
of the next low approaching the Gulf for Monday. Precipitable
water imagery shows that this next developing low located well
south of the AKPEN is already taping into deep tropical moisture
around 30N, which continues to advect northward into the Gulf.
Further west over the Central-Western Bering conditions are much
quieter with broad northerly flow scouring out much of the fog and
stratus over that area.

&&

.MODEL DISCUSSION...
The models remain in great synoptic agreement into Sunday evening
until timing differences with the next North Pacific low into the
Gulf begin to arise. The NAM especially has been consistently
about 6 hrs slower than any other model over the last 3 runs, and
was generally ignored in favor of the faster solutions which were
also closest to the currently forecast for timing. Regardless of
which model you look at, general trend in the models all indicate
deteriorating conditions late Sunday into Monday with good
forecast confidence.

&&

.AVIATION...
PANC...SE winds with areas of LLWS will continue for most of this
evening with continued strong pressure gradient along Turnagain
Arm and low level winds up to 50 kts. Even once the LLWS
diminishes late this evening, SE winds are expected to continue
overnight and increase again on Sunday afternoon. Otherwise VFR
conditions are expected to continue into Sunday.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
South to southeast flow will continue for Southcentral Alaska due
to the low in the Bering and ridging to the east. The winds will
bring warm air and moisture to the area resulting in rain for much
of Southcentral Alaska for the next couple days with the north
Gulf coast seeing the highest amounts. On Sunday a North Pacific
low approaching Kodiak Island will swing its front through the
Gulf and over Southcentral Alaska bringing heavier rain to the
north Gulf coast that will last for much of Monday. This pattern
will also result in stronger winds for many channeled areas like
Turnagain Arm. The strongest of which will be during the day
Monday as the pressure gradient builds.

&&

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

The North Pacific storm system slowly lifts north, crossing to the
eastern Bering tonight. The surface front with this occluded
system remains stationary across the Southwest mainland through
Sunday afternoon as a ridge over the northern Bering and a low in
the Arctic block its progression. The greatest rainfall amounts
are expected along the surface trough axis which stretches across
the Kuskokwim Delta and Valley. Strong low level southeasterly
flow over Bristol Bay limits precipitation on the lee side of the
ranges. Winds continue to be gusty through late Monday from the
south to east direction as the main low center stays positioned
over the Bering.

&&

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

The Alaska Peninsula and eastern Bering will continue to see an
active wet and windy pattern through Monday as low pressure
crosses to the eastern Bering tonight, then remains centered near
the Peninsula. A ridge builds across the western waters behind
the main low which brings a challenging forecast for the central
Bering as models are not in great agreement with the low position
Monday night through Tuesday. The afternoon package was updated to
increase precipitation along the eastern waters, to south of the
Alaska Peninsula, and kept a drier trend across the central
Bering. Low clouds and fog spread across the western Bering and
Aleutians

&&

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

The long term forecast begins Tuesday evening with the dominant
upper air feature being a large and sprawling closed low center
over the eastern Bering/Alaska Peninsula. Cloudier and showery
conditions will me the dominant weather mode over Southern Alaska.
After Wednesday the low slowly weakens and falls apart as weak
upper ridging looks to build in. The ECMWF is more in favor of
this scenario, but the GFS model is now trending in that direction
as well. By Friday and into the weekend, slow warming should
ensue, but plenty of lingering moisture and the intense solstice
sun should still support rather widespread shower activity.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Gale 352.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...DEK
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KH
LONG TERM...JA



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