860
FXHW60 PHFO 211345
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
345 AM HST Tue Jul 21 2026

.SYNOPSIS...
Light to occasionally breezy trades with an increase in showers.
Higher moisture lingering over Hawaii will create thicker overcast
and more frequent periods of rain through Wednesday. Recent trade
behavior will remain steady through mid week with a slight
strengthening of winds expected later in the week. Hurricane
Fausto will remain far east of the state the next several days but
may influence trade flow early next week.


&&

.DISCUSSION...
Early morning satellite imagery is depicting better organized
areas of thick clouds surrounding the island chain. This is in
association with a moist air mass lingering over the islands.
Veering winds within a deeper, moistened boundary layer will
yield the potential for areawide rain through tomorrow.
Precipitation has filled in across the state since midnight with
the majority of the smaller islands picking up a couple of tenths
to about a half an inch of rain, with localized greater than one
inch amounts, the past six hours. The quick pace and widely
scattered nature of these cells should keep any localized flooding
concerns at bay. Heavier, more intense pockets of rain may cause
nuisance low lying area flooding and street ponding today and
tomorrow.

This noticeable boost in statewide shower activity will likely
hang with us into Wednesday afternoon as this batch of higher low
to mid layer moisture lingers over the region. Typically drier
leeward communities may experience more frequent showers such as
enhanced shower coverage over lee Oahu in response to east
southeast wind convergence downstream of Maui County. After a
couple of days of weaker winds, trades will become more fresh as
northeastern Pacific surface high pressure building south tightens
the gradient across the area. Drier air filling in behind this
west-exiting moist air mass late Wednesday will ensure a drier
end of the week. Breezy trades, higher stability and limited
showers focused windward and upslope mauka will be the day-to-day
theme at week`s close.

Although decent northerly shear continues to impact Hurricane
Fausto, currently located about 650 nm off Cabo San Lucas, BCS,
he is slowly intensifying. NHC is forecasting Fausto to continue
on a slow and steady west to slight northwest track through Thursday.
A pick up in speed is expected with the majority of the numerical
model guidance keeping the storm just south of 20N into Saturday
as it nears 140W. If Hurricane Fausto stays on this west northwesterly
track, localized trade flow will be interrupted as the cyclone
passes northeast of the state early to mid next week.


&&

.AVIATION...
Latest radar and satellite imagery overnight depicts showers
impacting most windward sites across the state. Weather models
suggest that this will continue into the daytime hours today, with
chances for periodic spillover showers into leeward sites.
Otherwise, expect another day of moderate trades.

AIRMET Sierra is in effect for the windward side of most islands
due to ongoing shower activity. This is expected to continue until
at least the early evening hours Tuesday, when showers are roughly
estimated to decrease in coverage.


&&

.MARINE...
The trade winds will hold at mostly moderate speeds through
today as a subtle trough moves through the state. Trade winds
strengthen to fresh and locally strong speeds Wednesday and could
strengthen another notch late Thursday into Friday with widespread
strong trade winds possible towards the end of the work week.

The High Surf Advisory for south facing shores has been cancelled
due to the downward trend shown on the nearshore and offshore
buoys. The current south-southeast swell should slowly fade over
the next few days.

A powerful low pressure system tracked eastward well south of
Tasmania and New Zealand last week. OSCAT pass showed a wide fetch
of storm force winds with altimeter passes showing seas above 50
feet. This should translate into very long period forerunners
arriving as early as early Wednesday morning and steadily filling
in throughout the day Wednesday and peaking on Thursday out of the
south-southwest. Surf should reach advisory thresholds by
Thursday. The very long-period energy will make for inconsistent,
but powerful waves when they arrive. Several days of advisory
level surf is expected starting from Thursday and possibly
continuing through Sunday as reinforcing energy arrives over the
weekend.

Surf along east-facing shores will remain slightly below seasonal
levels today as the trades ease upstream of the islands. The Hilo
buoy this morning is showing a slight increase across the 12 to
14 second energy bands, which was likely generated by former TC
Elida. Easterly swell from TC Elida should peak on Wednesday near
seasonal levels. Stronger trade winds will also support an
increase of short-period energy by Wednesday, This weekend,
larger surf for east shores generated by Hurricane Fausto is
possible and could bring advisory level surf along east facing
shores as well.

Surf along north-facing shores will remain at flat to tiny levels
through the weekend.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Blood
AVIATION...Evans
MARINE...Kino