Area Forecast Discussion for Hawaii

Area Forecast Discussion   Issued: 05/20/2026 11:16:00 AM UTC

                        
166
FXHW60 PHFO 200116
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
316 PM HST Tue May 19 2026

.SYNOPSIS...
The moist trades we have been experiencing will give way to drier
trade winds beginning tonight. A consistent pattern of mostly
moderate but occasionally strong trades should continue well into
next week and perhaps beyond. Wind speeds will increase Wednesday
through Thursday night, possibly to wind advisory level, then
decrease slightly this weekend.

&&

.DISCUSSION...
Radar showed scattered showers over the Kona slopes this
afternoon, along with isolated windward and mauka showers on all
islands. Cloud cover ranged from mostly clear to overcast, with
the clearer conditions generally over leeward areas. Showers
should weaken around sunset, but a few will continue overnight
mainly windward and mauka.

Models remain consistent showing trade winds drying out and
increasing in speed through Thursday. Higher wind speeds,
potentially reaching wind advisory level, will arrive tomorrow and
continue into Friday and perhaps Friday night. Showers will
decrease both in number and intensity once the drier air arrives,
with the main drying occurring Wednesday afternoon into the
evening.

A consistent moderate to occasionally strong trade wind flow is
expected to continue through the weekend and well into next week
as a large surface high to our north remains strong enough to
dominate our weather. A band or two of enhanced moisture may
arrive after the weekend, but it`s too soon to time that out
reliably.

&&

.AVIATION...
Moderate to locally fresh trade winds will strengthen on
Wednesday as the atmosphere gradually becomes more stable. Periods
of MVFR conditions will primarily affect windward mountain areas,
and AIRMET Sierra for mountain obscuration may be needed tonight
and tomorrow morning, with drier conditions settling over the
islands Wednesday afternoon. Conditions are borderline for
moderate low level turbulence this afternoon, but the set up will
become increasingly conducive tonight and Wednesday, which will
require AIRMET Tango.

&&

.MARINE...
Locally fresh trades become strong with localized near-gales
during the latter half of the week. The Small Craft Advisory (SCA)
remains in effect and will eventually be expanded to all waters
as winds and seas build later this week.

Small, short to medium period NNW swell filling in
today. This will be followed later this week by a small NNW swell
emanating from a strong low near the Aleutian Islands. A series of
small, long period SSW swells supports near-average surf along S
shores. Meanwhile, strengthening trades maintain elevated surf and
short period fresh swell along E facing shores into next week.

&&

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


&&

$$

DISCUSSION...Parker
AVIATION...Wroe
MARINE...JVC