Area Forecast Discussion for Hawaii

Area Forecast Discussion Issued: 04/19/2026 04:57:00 PM UTC
                        
504
FXHW60 PHFO 190657
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
857 PM HST Sat Apr 18 2026

.SYNOPSIS...

Moderate trade winds will weaken and veer out of the east-
southeast across the western half of the island chain tonight as
low pressure deepens several hundred miles northwest of Kauai.
Shower activity should be low and focused mainly over windward
areas as high clouds briefly diminish. An upper-level trough will
will bring increased high clouds and renewed chances for isolated
heavy showers and thunderstorms Sunday afternoon and Monday.
Light winds favor chances for mainly afternoon showers Tuesday and
Wednesday, followed by rebuilding trade winds Thursday and
Friday.

&&

.SHORT TERM UPDATE...

Issued at 856 PM HST Sat Apr 18 2026

No changes made, previous forecast is on track.

&&

.AVIATION...

Light to moderate easterly trades among some land-sea breezes will
remain in place through the weekend under high pressure well north
of the Hawaiian Islands with a surface trough lingering to the
west. Overall, expect VFR conditions to prevail across most
terminals through the period.

No AIRMETs in effect.


&&

.MARINE...

A high pressure system far north of the state will slowly drift
eastward this weekend. Easterly trade winds diminish tonight as a
trough to the northwest of the islands develops into a weak low
pressure system by Sunday. The resulting weakness in the ridge
causes winds to veer southeasterly and diminish over the western
Hawaii region from Sunday into early next week. Late next week,
east to northeasterly trade winds begin to redevelop with weak
ridging re-establishing north of the islands.

A small pulse of medium period swell energy from the northwest
should produce a slight bump in north facing surf heights tonight
into Sunday morning. A small to moderate, medium period northwest
swell will move into the region by Monday night and continue
through Wednesday. A moderate, medium period northeast swell
arrives Tuesday and peaks on Wednesday, bringing moderate surf to
north-facing shores, before slowly declining through the end of
the week.

A medium-period south swell will continue to fade tonight,
allowing surf along south shores to return to background levels by
Sunday. A series of overlapping small south swells will move into
the region into next week. Surf heights along east-facing shores
remain on the smaller side due to weaker trade winds until the
arrival of the aforementioned northeast swell on Tuesday. Small
background energy from the west will be possible, especially later
in the week, from Severe Tropical Storm Sinlaku.

&&

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

&&

$$

UPDATE...Walsh
DISCUSSION...Wroe
AVIATION...Pierce
MARINE...Quesada