High Surf Advisory 32, NWS Honolulu, HI

Area Forecast Discussion
National Weather Service Honolulu HI
1008 AM HST Thu Aug 2 2018

.SYNOPSIS...
Breezy to locally windy trade winds will continue through the
weekend, supported by high pressure far north of the islands. Clouds
and showers will favor windward and mountain areas, with showers
remaining somewhat active the next few days. The trade winds will
ease early next week as the high weakens, with fewer showers
expected. It is still too soon to know if Hurricane Hector will
impact island weather next week.

&&

.DISCUSSION...
Breezy to locally windy trade winds are expected through the weekend
as a slow-moving, relatively strong surface high meanders around
about 1700 miles NNW of the islands. Clouds and showers riding in on
the trade winds will favor windward and mountain areas, and are
expected to be somewhat active the next couple of days due to the
presence of a mid-and upper-level trough that extends over the area
from the NE. In addition to modest instability, the trough will
supply periods of layered mid- and high-level clouds to island skies
through the weekend.

Trade winds will gradually diminish early next week as the surface
high to the NNW weakens. Shower intensity and coverage is also
expected to diminish as the trough aloft retreats to the W, and a
ridge aloft builds in from the E. With the ridge building toward the
area from the E and reducing vertical wind shear, Hurricane Hector,
currently over 2000 miles away from the islands, the ridge will
usher Hector into the central Pacific basin late this weekend. The
latest official forecast from the National Hurricane Center
indicates that Hector will be centered about 500 miles SE of the
islands early Tuesday morning. It is still too early to predict what
impacts Hector may have on our local weather around the middle to
later part of next week as track and intensity errors are rather
large in long range forecasts.

&&

.AVIATION...
Locally strong trade winds will prevail as a high pressure persists
far north-northwest of the state. AIRMET TANGO for low level
turbulence over and immediately south through west of the mountains
will likely to continue for at least the next couple of days.

Trade winds will focus most clouds and showers over windward and
mountain areas, with brief MVFR CIG/VIS in passing showers. Airmass
in the island vicinity will remain unstable enough for TCU and a
slight chance of thunderstorms over the interior areas of the Big
Island this afternoon, especially the leeward slopes. High clouds,
at or above FL200, will continue to stream over the state today.

&&

.MARINE...
Strong trade winds will continue into the weekend. The Small Craft
Advisory (SCA) is posted for all waters through Friday afternoon,
but will likely need to be extended into Saturday. Beyond that,
winds will likely start to taper off, but remain elevated over the
waters near Maui County and the Big Island.

The strong trade winds will maintain elevated choppy surf along east
facing shores into the weekend. Surf heights are just below advisory
criteria, an are expected to remain so over the next day.
As the winds start to weaken this weekend, expect the surf to begin
to lower.

Small southeast and south swells will maintain small background surf
along south facing shores through this weekend. A slightly larger
long-period south swell is expected to start spreading across the
island chain starting Monday, which is expected to bring surf back
to near the summer-time average along south facing shores early next
week.

The National Hurricane Center is issuing advisories on Hurricane
Hector in the East Pacific. Depending on the future track and
intensity of this system, surf may increase along some shorelines
around the middle of next week. The surf would likely initially
build along south and east facing shores of the Big Island, before
spreading to portions of the smaller islands. Stay tuned to the
latest updates on Hector, and its potential impacts on seas and surf
across the state next week.

See the latest Oahu Surf Discussion (SRDHFO), which was updated
Wednesday afternoon, for additional details on surf and swell.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST Friday for all Hawaiian
waters.

&&

DISCUSSION...Birchard
AVIATION...TS
MARINE...M Ballard