Area Forecast Discussion
Issued by NWS
FXAK67 PAJK 281313
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
513 AM AKDT Tue Mar 28 2017
.SHORT TERM...Satellite imagery and surface analysis indicate a
low SW of Haida Gwaii and another low off the AK peninsula. The
first low will move NE into BC this morning. The other low will
drift NW with a series of impulses propagating NWd across the gulf
into the N gulf coast. Models in decent agreement with the
strongest impulse impacting the gulf coast overnight into Wed.
This scenario will keep most precip confined to areas W of Cape
Fairweather and southern panhandle with SCT-NUM showers across
majority of AOR. Model solutions continue to diverge with the
strength and track of the low SW of Haida Gwaii but general
consensus is for the low to move into BC remaining S of Dixon
Entrance or just clipping southern portions of Misty Fjords.
Advisory level winds/seas will prevail over the gulf today as
active weather persists. Expect advisories to develop across Cross
Sound due to building seas and rising Ely winds. Also, marginal
advisory level southerlies over N Lynn this morning will diminish
by late this morning as the gradient relaxes. Otherwise, some
breaks in sky cover early this morning combined with light winds
has allowed some patchy fog to develop over the inner channels and
expect this to dissipate by mid to late morning. Confidence is
above average in precip along the N gulf coast, outer coast N of
PASI and the northern panhandle tonight with lower chances over
the central/southern panhandle. With lower PoPs and greater
potential for some breaks in clouds, added some patchy fog to
inner channels over the central and southern panhandle.
Given the persistent SW, continue to think rain will be primary
ptype with snow over the higher elevations over N and heavier
showers moving onshore the N gulf coast. Minor accumulations
possible, but would be surprised if more than an inch or two.
Forecast in good agreement with model guidance, so used EC/NAM for
any adjustments. Forecast confidence remains average.
There is a small change in timing on Wednesday for the front that
is moving into the eastern Gulf. Model runs have increased the
speed this front is moving across the Gulf and this is reflected
in the current forecasts. In addition, wind speeds will be
stronger along the outer waters with this front with a large swath
of Gales across most of these waters.
The upper level trough will move through Southeast AK in
conjunction with the front and that will allow an upper level
ridge to briefly move across Southeast on Thursday. While it
appears that there will still be a few rain/snow showers lingering around
the area Thursday, this ridge may be potent enough to suppress
most of the precipitation and might even provide a break or two
in the clouds. This possibility is being indicated on the 06Z
model runs on both the NAM and GFS.
Models are consistent with bringing the next system into Southeast
Thursday night and precipitation persisting with this one through
most of the weekend across the region.
MARINE...Small Craft Advisory for PKZ021-022-031-036-053. &&
Visit us at http://www.weather.gov/Juneau