Scientific Forecaster Discussion
Southcentral and southwest Alaska forecast discussion
National Weather Service Anchorage Alaska
545 am akst Friday Jan 30 2015
Analysis and upper levels...
high pressure continues to build in across the Bering and is now
starting to extend out over the western part of Mainland Alaska.
For now this is keeping cold northeasterly flow over southwest
Alaska but that is already diminishing. The high building in is
also pushing precipitation away from Mainland Alaska and the
the models are in good agreement in the short term. There are
minor differences with a weak low in the Gulf but impacts from
those differences will be limited. Discrepancies develop in the
middle term with two different lows. The first is a triple point low
moving towards the Gulf Saturday. The Gem is much stronger with
this low than the other models. The other problematic low is a
low that is moving north near the western Bering Sea Friday night.
The Gem is slower than the other models with its track.
Short term forecast southcentral Alaska (days 1 and 2)...
quiet weather will be the rule for the next couple of days. A weak
front is dissipating over south central this morning. A strong
ridge of high pressure will build in from the northwest. This will
keep approaching systems well away from the area...stalling just
to the south of Kodiak Island. An offshore regime will set up
that will usher in dry air...which should keep fog away from most
Short term forecast southwest Alaska (days 1 and 2)...
northerly cold outflow winds will continue for the next couple
days as the surface pressure gradient remains favorable.
However...temperatures will being to warm slightly as a high
pressure system above the surface will bring warmer air overhead.
Cloud free and slightly below normal temperatures will persist
Short term forecast Bering Sea/Aleutians (days 1 and 2)...
most of the Bering will remain under clear or partly cloudy
conditions with a couple of exceptions. The western Bering will be
clipped by a frontal system today with low clouds and gusty
southerly winds. The Alaska Peninsula and eastern Aleutians will
be clipped by a weakening disturbance today bringing some snow and
rain showers with it...then again with another front on Saturday
bringing a better chance for light precipitation.
Long term forecast (days 3 through 7)...
by late this weekend...there is very good forecast confidence that
that ridge currently residing over the western Aleutians will
spread over the southern Mainland...keeping below normal
temperatures...clear skies...and light winds to most interior
locations (including southcentral). Areas along the Gulf Coast
will continue to see gusty outflow winds...especially in the
Valdez area that will remain under the influence of the cold air
in the Copper River basin. Forecast will remain very similar into
early next week as the ridge continues to hold. Later into next
week there remains very good model agreement next Wednesday as an
Arctic trough quickly dives through the Mainland...dragging down
even colder air with a slight chance of snow to the area. Since
this will be fairly dry and fast moving feature...any snow chances
will likely be short lived and light. The more important takeaway
from this system will be the cold air associated with it that have
the potential to bring the coldest temperatures of the season to
the Mainland into late next week.
Over the Bering Sea region ridging will continue through the
middle of next week...with a nearly stationary upper level low
keeping a chance of rain and snow confined to the akpenn and
eastern Aleutians. Otherwise very benign weather for early
February will take over much of the Bering Sea with dry conditions
and no major wind producing systems on the horizon.
Marine...gale 127 131 132 138 150 155 172 178.
Synopsis and model discussion...dk
southwest Alaska/Bering Sea/Aleutians...ml