Waipahu, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

914
FXHW60 PHFO 050537
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
737 PM HST Sat Jul 4 2026

.SYNOPSIS...
A ridge of high pressure will remain anchored in place north of
the Hawaiian Islands for the foreseeable future. Easterly trade
winds will continue to blow across the region through the end of
next week. Shower activity will remain limited with brief
increasing trends on Tuesday, and again from Thursday through
Friday as a weak easterly wave moves from east to west across the
state. Any showers will that develop in this trade wind pattern
will favor windward mountain slopes of each island during the
overnight to early morning hours.

&&

.SHORT TERM UPDATE...
Easterly trade winds will continue through the end of next week as
the subtropical ridge remains locked in place north of Hawaii.
Subtle changes to the wind speeds should be expected each day. Mostly
stable weather conditions are forecast for the next seven days
with slight increases in shower activity on Tuesday, and again
from Thursday through Friday as a weak easterly wave passes from
east to west across the island chain. Rainfall amounts over the
next seven days will remain limited due to large scale stability.

The afternoon forecast grids look good. No evening updates.

&&

.PREVIOUS DISCUSSION...
Issued at 336 PM HST Sat Jul 4 2026
High pressure just north of the Hawaiian Islands will remain the
dominant feature, maintaining stable moderate to breezy trades
over the next several days. The remainder of the islands will see
little rainfall as a brief period of drier conditions can be
expected through tonight.

Trades gradually strengthen by the turn of the week as the
aforementioned high just to the north of the islands builds and
meanders a bit to the southeast. Conditions are expected to remain
stable, focusing typical shower activity to windward and mauka
areas through the early portion of the next week.

By the end of next week, excess residual moisture associated with
Post-Tropical Cyclone Douglas may extend to the island chain by
way of breezy trade wind flow. This may bring increased shower
activity over initially windward and mauka locations and may
spread further into leeward portions of the state toward the end
of the forecast period.

&&

.AVIATION...
Moderate to locally breezy trades will continue through the
holiday weekend, with a slight uptick in speed heading into
Sunday. Low clouds and showers associated with a nearby upper low
will move into windward and mountain areas with the trades
overnight. Some spillover showers into leeward sites is possible
overnight into late morning Sunday, however VFR conditions are
broadly expected, with localized MVFR possible mainly for windward
sites.

AIRMET Sierra remains in effect for mountain obscuration across
windward sections of the Big Island. Looking upstream on satellite,
conditions will likely improve overnight, however lingering shower
activity may still persist early morning Sunday. Other islands may
need to be considered as well, with moisture moving in overnight.

AIRMET Tango remains in effect for moderate low level turbulence
over and downwind of terrain for all islands. This AIRMET will
likely continue through the weekend.


&&

.MARINE...
Issued at 336 PM HST Sat Jul 4 2026
A high pressure ridge north of the Hawaiian Islands will keep
trade winds blowing across the region through the week. A Small
Craft Advisory (SCA) for the typical windy waters and channels
around Maui and the Big Island continues tonight. The SCA area
expands to include all coastal marine zones around Maui County,
including Kaiwi Channel, along with leeward Oahu as winds
increase slightly on Sunday. Minor fluctuations in wind speeds may
allow for brief periods of additional zones to fall into and out
of the SCA coverage area over the next several days.

A small, long period south swell will fade tonight as an overlapping
moderate, long period south-southwest swell fills in, boosting south
shore surf heights to near High Surf Advisory levels Sunday and
Monday. This swell will remain the primary south swell during the rest
of next week as it gradually fades beginning on Tuesday.

Surf along east facing shores will remain rough and choppy through
the forecast period as moderate to locally strong trades hold. A
slight bump in surf along north facing shores will dwindle tonight
into Sunday as a small, west-northwest swell fades. Surf along north
facing shores then remains flat to tiny into next week.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory from 6 AM Sunday to 6 PM HST Monday for
Kaiwi Channel-Maui County Leeward Waters-Maui County Windward
Waters-Oahu Leeward Waters.

Small Craft Advisory until 6 PM HST Monday for Alenuihaha
Channel-Big Island Leeward Waters-Big Island Southeast Waters-
Maalaea Bay-Pailolo Channel.

&&

$$

SHORT TERM...Bohlin
PREVIOUS DISCUSSION...Foster
AVIATION...Evans
MARINE...Quesada