Area Forecast Discussion
Issued by NWS
FXAK67 PAJK 261325
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
525 AM AKDT Sun Mar 26 2017
.SHORT TERM...Satellite imagery shows mid and high clouds
expanding N across the panhandle early this morning as a surface
low deepens SW of Haida Gwaii. This will move N to the far SE
gulf by late Sun afternoon and push NNW across the gulf overnight
into Mon. Advisory level winds over PKZ041-042 will continue to
increase today with gales expected by this afternoon. Advisory
level winds will prevail over Cross Sound, western portions of Icy
Strait and near the ocean entrances of S Chatham and Sumner
Straits. Winds will begin to ease this evening as the surface low
drifts towards the central gulf. Offshore gradient over central
and northern panhandle inhibiting precip early this morning.
Heaviest precip over far N panhandle where northerly winds
persist. Trend for diminishing precip over the N/Ctl panhandle
will continue this morning while chances increase over the
southern panhandle as the developing low pushes an occluded front
into the region. WAA with the occluded front will result in mainly
rain over the southern panhandle with ptype becoming diurnally
driven heading N. As temps cool tonight, snow will likely mix with
-RA over the N half of the area with little to no accumulation.
Current forecast represents this well. Minor adjustments made for
local effects and to reflect current conditions.
.LONG TERM.../Mon through Sat/ Looks like a fairly active weather
pattern this week with SW flow aloft steering a series of weather
fronts toward the region. Satellite imagery shows three main
cyclones over the eastern...central...and western Pacific that
weather models bring to SEAK during the long term forecast period.
The E Pacific cyclone is currently centered west of Vancouver
Island. Models indicate a sfc low approaching from the S today
will slowly move NNW along the coast Mon causing widespread
precip. Snow will be part of the mix Mon north of Frederick Sound
but all rain at lower elevations south of there. A band of gales
along the front will affect the outside waters Mon.
Another weather system ejects out of the system currently centered
over the central Pac south of the Aleutians and affects SEAK Tues.
There are some differences on the evolution of this system but
more rain and snow likely with snow or mixed snow/rain primarily
north of a line from Juneau to Yakutat.
The western Pac system is now just east of Japan. Global models
indicate a large scale upper trough and surface low center develop
near the dateline mid week in response to this W Pac system
stengthening. A transitory upper ridge builds downstream over the
E Pac in the Wed-Thur time frame. Expect a cloudy but potentially
dry period centered about Thurs this week. Freezing levels could
rise to about 5000 feet over the far southern panhandle Thurs-
early Fri. This brief push of warmer dry air late week will be
quickly replaced if the strengthening system continues to move
east into the panhandle as models indicate. Ensemble solutions
show wetter weather is likely again next weekend.
Used NAM/GFS to maintain higher PoPs Tues and GFS to lower PoPs a
tad Thurs otherwise no change to existig forecast. Forecast
confidence in model trends is average.
MARINE...Gale Warning for PKZ041-042.
Small Craft Advisory for PKZ022-036-043-051-052.
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