Area Forecast Discussion
Issued by NWS Anchorage, AK
FXAK68 PAFC 281211
Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
411 AM AKDT FRI OCT 28 2016
.ANALYSIS AND UPPER LEVELS...
Upper level ridging has started to push into the Southern
Mainland this morning, bringing mostly clear skies, lingering weak
outflow winds, and surface pressure rises. A weak elongated wave
tracking over the Kenai Peninsula and Susitna Valley during the
overnight period is seen in satellite imagery tracking some cloud
cover over these areas.
Meanwhile to the west, satellite imagery indicates a deep fetch
of moisture being pushed north across the Central and Eastern
Aleutians/Bering. A surface front sits beneath this upper jet,
slowly intensifying and bringing gusty winds to the Central and
Eastern Aleutians/Bering. Further West...Gusty winds and
precipitation have started working their way into the far Western
Aleutians and Bering as the parent low tracks into the Western
Models are in generally good agreement during the overnight period
as the front across the Eastern Bering continues to intensify
slightly and push towards the Western Coast. There is still some
difference however on the manifestation of a triple point low
along this baroclinic zone as it approaches The Western Coast.
This has important implications for the intensity of gusts across
Bristol Bay and coastal portions of the Kuskokwim Delta, so a
middle ground solution was used for the overnight forecast
PANC...VFR conditions and light winds will persist.
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
It should be a rather quiet day around southcentral Alaska with a
weak upper level wave moving through this morning that is only
strong enough to bring in a few clouds. High pressure building in
behind this wave will clear out skies briefly before clouds from
the next front move into the region from west to east tonight.
Temperatures will be warming up with this front and precipitation
type will be mostly rain with the north Gulf coast and Kodiak
Island getting the majority of the rain. Leeward areas of the
Kenai Mountains and Chugach Range should mostly downslope out the
rain with just a chance at lower levels on Saturday.
.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
A powerful warm front will move into the Eastern Bering Sea today
bringing storm force winds to the coast. Some gusts across the
Kuskokwim Delta will reach close to 70 MPH, especially along and
near the coast. High seas and heavy surf will impact coastal
locations prone to strong southerly winds, but no major
erosion/coastal flooding is expected as the main surge is not
expected to occur during high tide. Moderate to heavy rain will
impact coastal locations with lighter inland rain owing to some
degree of downslope drying. The front moves north tonight with a
cold front moving inland overnight and Saturday. The front will
stall across the Alaska Range Saturday night with largely dry
conditions moving in elsewhere as drier air filters in behind the
.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
A strong front will track east of the Pribilof Islands into the
Eastern Bering Sea today bringing widespread gales and some low
end storm force winds. Some near hurricane force wind gusts will
be possible across the complex terrain over the far western Alaska
Peninsula. The front will move inland across Southwest Alaska
tonight with cold air advection spreading over the entire Bering
Sea. Expect widespread gale force winds and instability driven
Attention will quickly turn to a developing hurricane force low
which is expected to move into the Central Aleutians Saturday
afternoon then track into the Central Bering by Sunday. The
strongest core of westerly winds along the back side of this
powerful bent-back occlusion will impact Adak and Atka, although
the details of the low track are still somewhat uncertain. As a
result, a high wind watch has been issued highlighting the
.LONG TERM FORECAST (Days 3 through 7)...
Beginning Sat night an upper ridge over the eastern half of
mainland AK will reside along the eastern flank of a low that
covers all of the Aleutians, Bering, Kamchatka and western AK. A
decaying front will persist over the Alaska and Aleutian
For now the forecast is closer to the EC in that it builds the
high into the northern Bering, which causes the low to head west.
Confidence is not high with this trajectory since it depends on
ridge building which other models downplay. Given this solution,
by Tue the low in the southern Bering reaches the northwestern
Bering where it spins through Thu. In the meantime the front over
the mainland slowly decays, and the next wave moving around the
upper low brings a surface low into the southern Gulf on Thu.
The Bering and Aleutians can expect significant rainfall with the
low and associated front into Tue, with Gales and Storms through
Tue diminishing to Small Crafts by midweek. Rain and wind will
also affect southwest AK through Tue before diminishing.
Southcentral will receive rain, initially from the decaying front,
and then beginning on Mon from a front associated with the Bering
low. Much of the precipitation from these events will be on
windward sides of mountain ranges.
PUBLIC...High Wind Watch...187.
MARINE...Storm...155 160 165 172 180 414.
Gale...150 170 173 174 175 176 177
178 179 181 185 411 412 413.
SYNOPSIS AND MODEL DISCUSSION...TP
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JA