High Surf in Hawaii, July 16 to 21, 2016

Area Forecast Discussion
National Weather Service Honolulu HI
340 AM HST SAT JUL 16 2016

.SYNOPSIS...
Hot and muggy conditions will continue through the week. Trade
winds will remain through today, bringing morning showers with
clearing expected by the afternoon. Winds will become light from
Sunday into Tuesday as the remnant low of Celia passes a couple
hundred miles north of the islands. Deep tropical moisture will
move over the islands from Sunday through Wednesday, fueling
locally heavy showers for both windward and leeward areas. Trade
winds will return Wednesday, possibly becoming breezy Thursday and
Friday as the next tropical system approaches.

&&

.DISCUSSION...
High pressure centered far to the northeast will maintain trade
winds over the state through today. Showers will linger into the
morning hours today before clearing over leeward locations while
some afternoon showers are still expected over the windward areas
and mountains. The leeward slopes of the Big Island will see
cloudy skies in the afternoon with scattered showers.

Moderate trade winds will continue into tonight with typical
windward and mauka showers. Sunday, the remnant low of former
Tropical Cyclone Celia will start to modify island weather. The
low is expected to track north of the state from Sunday through
Tuesday. Winds will shift from the north northeast Sunday as the
low passes by to the north. Monday, winds will be light and
variable before turning from the southeast Monday night as the low
moves northwest of Kauai. Moisture will increase over the eastern
end of the state Sunday and Monday as a cloud band extends south
from the low over the Big Island and Maui County. The enhanced
moisture will bring increased chances of showers and locally heavy
rainfall. This band will move west over Oahu and Kauai Tuesday
allowing for increasing showers. Light winds both Monday and
Tuesday will allow late morning sea breezes to develop with the
potential for locally heavy showers in the afternoons. A brief
return of trade wind weather is expected Wednesday before the now
distant Hurricane Darby potentially affects island weather.

Dew point temperatures will remain in the low 70's for the
foreseeable future as former and future tropical systems continue
to bring enhanced moisture across the island chain. Dew points in
the low 70's equate to quite uncomfortable conditions, especially
when trade winds diminish.

&&

.AVIATION...
There is an extensive low cloud moisture field upwind of the
island. There are a few breaks within this mass but the breaks
will be short. With this said...AIRMET SIERRA for mtn obscuration
for the smaller islands will likely continue well into the morning
hours...and may extend into the afternoon hours despite the
outlook for less frequent windward and mauka showers.

The Big Island sits at the eastern fringe of the cloud mass where
clouds are less concentrated. So the windward Big Island will be
grazed occasionally by this moisture field. We will continue to
monitor if an AIRMET SIERRA is needed or not. So far the coverage
is not enough to warrant one.

Otherwise...VFR conditions prevail.

The trade wind are moderate to locally strong in strength. However
the inversion is weak and elevated near 10k feet. Thus, any low
level turbulence will be light at best.

&&

.MARINE...
A small-craft-advisory (SCA) is posted for the typically windier
waters around Maui County through today.

The remnant low of Tropical Cyclone Celia will pass between the
islands and high pressure to the N Sunday, and early this week,
causing winds to turn from the N and diminish. Winds will become
light and variable Monday and into Tuesday, and then increase from
the SE and E Tuesday afternoon and Wednesday. Latest guidance
indicates seas near Kauai and Oahu will increase to near 10 feet
as seas/swells increase due to the gradient between former Celia
and the high pressure to the N, requiring a SCA for seas rather
than wind.

A SSW swell is bringing below advisory level surf to S facing
shores today. This swell will subside Sunday and early this week.
A long period E swell generated by Celia will effect the islands
today but surf will remain below advisory levels. Larger surf
along east facing shores is anticipated Sunday and Monday with a
High Surf Advisory anticipated. A second long period E swell from
distant Hurricane Darby is expected late next week. See the Oahu
Surf Discussion (SRDHFO) for more details.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST this evening for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel.

&&

Morrison...Discussion and Marine
Lau...Aviation