Scientific Forecaster Discussion
Southcentral and southwest Alaska forecast discussion
National Weather Service Anchorage Alaska
454 am akdt Friday may 29 2015
Analysis and upper levels...
a broad upper ridge along the Mainland has an axis that extends
across southcentral to the northwest coast with the surface center just
south of the Gulf of Alaska. Overall...conditions are tranquil
across the southern Mainland with patchy fog along the coasts. To
the west an organized low continues to slowly track north with a
frontal boundary nearly stationary across the eastern Bering. Low
clouds and patchy fog are mainly along the southwest coast with
the rain band along the front slowly approaching. Winds are
starting to taper down with gusty gales confined north of the low
center early this morning.
Models are in good agreement with the overall synoptic pattern
through the weekend. The forecast continues to advertise above
normal high temperatures through the weekend as the ridge builds
across the southern Mainland. The low pressure system across the
west retrogrades west over the weekend...however this system
continues to actively move shortwaves from west to east across
the Bering mainly bringing showers as the system fills and
Short term forecast southcentral Alaska (days 1 and 2)...
high pressure will remain over south central Alaska through
Saturday night with warm and dry conditions. At the low
levels...offshore flow is expected during the night and morning
hours...with weak or non-existent sea breezes in the afternoon.
Most areas will see the warmest temperatures of the year so
far during the next few days...and some daily record temperature
maximums could be set on Saturday and possibly Sunday as well.
Short term forecast southwest Alaska (days 1 and 2)...
Much of southwest Alaska will experience a warming and drying trend today
and Saturday. The front decaying over the eastern Bering will
keep coastal areas clouds with a chance of rain during the same
Short term forecast Bering Sea/Aleutians (days 1 and 2)...
As the low exits the Bering...cyclonic flow will keep clouds and diminishing
showers across the Aleutians and western Bering through Saturday.
The decaying front will keep a chance of rain over the eastern
Bering and Alaska Peninsula during the same period.
Long term forecast (days 3 through 7)...
hot and dry conditions will persist through the weekend across
much of the southern Mainland beneath a high amplitude ridge
extending from the Chukchi Sea over Mainland Alaska and into the
northeast Pacific. The pattern will then begin to change by early
next week as the ridge is bisected by a potent shortwave trough
dropping down its eastern periphery along with a broad upper low
moving eastward across the North Pacific. This will usher in a
moderating trend as temperatures return to near or slightly above
normal values by the middle of next week...with chances for
diurnally driven convection beginning to increase as colder air
moves in aloft. Meanwhile...another low moving off of the
Kamchatka peninsula this weekend looks to stay south of the
Aleutian chain as it pushes eastward across the North Pacific next
week. This will result in benign conditions over much of the
Bering beneath weak upper level flow.
Synopsis and model discussion...kh
southwest Alaska/Bering Sea/Aleutians...ds