Scientific Forecaster Discussion
Southcentral and southwest Alaska forecast discussion
National Weather Service Anchorage Alaska
136 PM akdt Tuesday Jul 29 2014
Analysis and upper levels...
there is an upper level low over the Gulf of Alaska. A strong
blocking ridge is over the central/eastern Bering Sea. An upper
low is lurking off to the southwest of the western Aleutians. This
is an "omega block" and is a stable pattern.
the numerical models are in very good agreement. Considering
this...and the stability of the pattern...forecast confidence
today is high.
Short term forecast...
For south central Alaska...some (mainly mountain) showers are
possible this evening with some residual moisture and the flow
aloft still a little cyclonic. Some "wrap around" moisture from
the Gulf low is pushing into southern Alaska from the east will
provide some rain/showers to the eastern Copper River basin and
the eastern Gulf Coast/eastern Prince William Sound. This will
taper off on Wednesday and come to and end Wednesday night.
Otherwise mainly dry conditions (some diurnal mountain showers are
possible) are expected across the area into Friday afternoon as
the Bering ridge builds eastward across southern Alaska.
For southwest Alaska...dry conditions are expected through
Thursday night as the ridge dominates the weather picture. Some
moisture may slide around the ridge and enter southwest Alaska
from the northwest on Friday for a chance of showers.
For the Bering Sea/Aleutians...the pattern changes very little
during the week. The Bering ridge will keep precipitation and
southeasterly winds associated with the low southwest of the
western Aleutians confined to areas generally from Atka west.
Long term forecast...
the Omega blocking over the central to northern Bering Sea will
continue through this upcoming weekend. The predominate feature
will be stratus and fog with light winds for the Bering Sea. The
southcentral Alaska will be under the influence of weak shortwave
ridging keeping most of the region slightly warmer than average
with showers along the mountains through the weekend.
Ludwig/period Jul 14