830
FXHW60 PHFO 170134
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
334 PM HST Wed Jul 16 2025

.SYNOPSIS...
A high pressure ridge will remain in place north of the Hawaiian
Islands into the first half of next week. Expect moderate to breezy
trade winds through Thursday. Winds will ease slightly to more
moderate speeds Friday through Sunday. Expect showers to focus
mainly along windward and mauka slopes especially overnight and
early morning. An increase in shower activity and instability is
expected as early as late Thursday into Saturday as an upper level
low develops northwest of the state. Typical summertime, stable
trade wind weather is expected to gradually return Sunday onward
as an upper level ridge builds over the region.

&&

.DISCUSSION...

A surface ridge north of the Hawaiian Islands is producing
moderate to locally breezy trade winds. Afternoon satellite and
radar imagery show showers have trended down since this morning.
Clouds and isolated showers are favoring windward and mauka ranges
with a few clouds and showers developing along the Kona slopes
this afternoon. Chances of showers will increase tonight along
windward and mauka areas due typical diurnal trade wind pattern
and as pockets of moisture move from east to west within the
tradewind flow and a clouds and showers clearing along Kona slopes
as land breezes develop. Similar day time conditions experienced
today is expected during the day Thursday.

Forecast remains on track, with chances of clouds and showers
increasing late Thursday as an area of near to slightly above
normal moisture moves east to west as a weak upper level low
develops northwest of Kauai. This combination of upper level and
low level moisture will lift the temperature inversion heights to
around the 7,000 foot range, increasing rainfall activity into the
scattered to numerous range, mainly over windward and mountain
areas in the overnight to early morning hours with a few showers
making it to leeward areas of the small islands. There is also a
non-zero chance of isolated thunderstorms developing north and
west of Kauai. The EC model guidance is showing a more robust
signature than the GFS which is not generating enough confidence
put in the forecast at the moment. Expected rainfall totals during
the Friday and Saturday time period, are expected to remain
between 0.10 inch to 0.50 inch where the higher amounts expected
in and around terrain favored locations.

Stable summertime trade wind pattern is expected to gradually return
Sunday. A drier airmass is expected to filter in first for the
eastern half of the state as the upper level level shifts
northeast of the state. The upper level low is expected to weaken
into a trough and exit northeast of the state by early next week
and the lingering moisture plume should push north and west
allowing for drier and more stable conditions develop state wide.


&&

.AVIATION...
A locally breezy and rather stable trade wind flow will persist
through Thursday. Periods of MVFR ceilings and visibility in SHRA
will be confined to windward areas of all islands, as well as the
South Kona slopes of the Big Island during the afternoon and
evening hours. AIRMET Tango for low level turbulence will remain
in effect below 7,000 ft over and downwind of terrain.

Trade winds will ease slightly Friday and Saturday, and shower
activity may increase as the atmosphere becomes less stable.


&&

.MARINE...

High pressure will remain far northeast of the state through the
rest of the week. Fresh to locally strong trades will persist
through Thursday, then wind speeds may drop slightly as a weak
low level trough develops in the easterly flow and moves across
the state Thursday night into the weekend. A Small Craft Advisory
(SCA) remains in effect for the typical windy areas around Maui
County and the Big Island through Thursday.

A fading medium period south swell combined with a fading south-
southeast swell will maintain below summer average surf on the
south facing shores through tomorrow. A slight bump in surf is
expected this weekend as a new long-period southwest swell arrives
from the Tasman Sea, along with a new small short-period south-
southeast swell. The Tasman swell is expected to peak on Saturday,
with surf heights topping near the summer average before
gradually declining into early next week.

Surf along east facing shores will continue to remain rough and
choppy due to the fresh to locally strong trade winds and a small
short-period northeast swell that is expected to fill in this
weekend. Surf along north facing shores will remain nearly flat
through the weekend.

Minor coastal flooding along the shoreline and in low-lying
coastal areas will be possible around the daily high tide
starting Monday of next week due to peak monthly tides and higher
than predicted water levels at select locations.



&&

.FIRE WEATHER...

Trade winds will remain in the moderate to locally breezy range
through Thursday before weakening slightly into the weekend.
Shower trends are expected to increase as early as Thursday night
through Friday and hold into Saturday night. A weak upper level
disturbance will near northwest Kauai late Thursday and Friday,
increasing instability slightly. At the same time a area of low
level moisture will move from east to west across the state,
increasing chances of showers mainly for windward a mauka areas
but could also spill over to leeward areas of the smaller islands
at times as the temperature inversion heights increase. Drier and
more stable weather is expected to gradually return from east to
west Sunday into early next week. Borderline fire weather concerns
over leeward areas may be of concern middle of next week as
breezy, dry and stable trade wind pattern develops.



&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST Thursday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.


&&

$$


DISCUSSION...Almanza
AVIATION...Wroe
MARINE...Farris
FIRE WEATHER...Almanza