Area Forecast Discussion
Issued by NWS
FXAK67 PAJK 182325
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
225 PM AKST Sat Feb 18 2017
.SHORT TERM...The latest satellite imagery shows scattered open
cell showers over the Gulf of Alaska drifting northwest. The
Yakutat area that has seen these showers move onshore the past 24
hours will see the shower activity remain offshore as the flow
becomes more offshore. The rest of the forecast area is mostly
clear with relatively light winds. There will be some isolated
areas with north winds 10 to 15 mph from the interaction of the
weak high in Canada and the developing inverted trof over the
panhandle. This interaction will increase the offshore flow to
keep the forecast area dry and mostly clear. There might be some
localized patchy fog near the Petersburg area and the west side of
POW late tonight.
There is some indication that the winds will be gusty from the
northeast near downtown Juneau and Douglas tonight and persisting
into Sunday morning. The pressure gradient will tighten along the
coast mountains along with a surface inversion that will develop
from the clear skies to form a weak Taku wind scenario. Wind
speeds will be near 20 mph with gusts from 30 to 35 mph. As the
pressure gradient relaxes through Sunday so will the winds.
Low temperatures will fall into the teens over the far north to
the upper 20s over the south with the clear skies. The temps will
rebound through Sunday with highs in the lower 40s.
Overall there was not much change in the forecast and there is
above average forecaster confidence through Sunday afternoon.
.LONG TERM...Narrow upper trof over the E gulf will weaken and drift
slowly E, and should move E of the area by Tue afternoon. A fairly
strong shortwave trof will move E into the N gulf Mon night, then
weaken as it moves across SE AK Tue into Wed. Yet another
shortwave trof will move into the gulf for Wed but this one looks
like most of the energy will remain offshore as it moves SE. Upper
ridge should build over the gulf for late week. May have a
shortwave trof move through the ridge into SE AK for the weekend.
For Mon into Mon night, most shower activity with the narrow upper
trof will stay over the gulf although some snow showers may get
into the NE gulf coast Mon night in response to the stronger
shortwave moving into the N gulf.
For Tue into Wed, precip chances will be highest along the E gulf
and outer coast area, but even here POPs will generally peak at
chance levels. More E inner channels should only see some clouds
with more clouds expected over the N than S area.
For late week, some precip will be possible with next shortwave
but better threat for it may be along the outer coast. Models
differ some on exact track of system though so kept a broader
area of chance POPs for it Thu. Upper ridge should dry things out
somewhat later Thu night and Fri.
Next weekend, shortwave moving through the ridge will probably
bring another threat for precip to the area. It also looks a bit
warmer as well. Models differ on how much of the shortwave energy
will dig into the NE gulf so precip potential varies amongst them.
Used WPC POPs to handle this system, which is leaning toward more
energy digging into the NE gulf, which would result in higher
threat for precip.
MARINE...Small Craft Advisory due to Seas for PKZ041-042.
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