FXAK67 PAJK 191332

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
532 AM AKDT Mon Aug 19 2019

.SHORT TERM...On Monday, clouds will be on the increase from south
to north as another low pressure system tracks northeast over the
North Pacific towards the Dixon Entrance. A gale-force low will
push a swath of rain into the Southern Panhandle by Monday
evening. Rainfall, heavy at times, will continue to push northward
on Tuesday as the low pressure systems heads closer to the
region. Through Tuesday night, 1-2.5" of rain is possible across
the Southern Panhandle with lesser amounts further north. As of
late Sunday evening, models have clustered on the track of the
low in the southeast gulf Monday night into Tuesday but then
quickly begin to diverge Tuesday night into Wednesday on how
quickly the feature jumps ashore. While confidence is not great,
we acted to slow the storm Tuesday night. And instead of pulling
up the coast for a landfall over Baranof/Chichagof Island, the low
now looks to creep into the southern Panhandle region. While this
is not unanimous with the ECMWF more quickly guiding it onshore
well into Canada by this time and others directing the main energy
toward the north coast of BC, we feel it covers a middle ground
of possibilities rather than keeping the storm track farther west
and north. How quickly the system does move into Canada and how
far south and east the low eventually tracks will directly impact
how far north bands of moderate to heavy rain reach and how
quickly. For instance, some models leave Juneau high and dry
whereas others bring the bands of heavy rain. IVT values for this
system are significant enough to support bands of moderate to
heavy rain.

Finally, there is the potential for some stronger winds over
Prince of Wales and the Ketchikan/Clarence Strait corridor late
Tuesday into Tuesday night as the system churns west of Haida
Gwaii. Look for at least 25 to 30 kt of wind, and potentially gale
over Clarence Strait while gales look likely over marine zone 41.

.LONG TERM...Beyond this mid-week storm, it looks typical of
August where the a strengthening storm track guides Pacific
systems with rounds of rain for our area. Between such systems
like Wednesday/Wednesday night, it looks probable for a round of
light shower activity, so we do not see substantial dry periods.
We spy one significant wave nearing the eastern gulf
Thursday/Friday. While early to tell, breezy conditions appear a
sure bet Thursday for at least the coast. We keep temperatures in
the 50s for much of the week to account for the wetter rain cooled
air with diurnal ranges kept around 10 degrees or less.

While confidence in details of systems is low beginning Tuesday
night/Wednesday, we do have relatively high confidence in the
wettest pattern we have seen all summer upon us.


.AJK Watches/Warnings/Advisories...
MARINE...Small Craft Advisory for PKZ012-041-042-051.




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