Area Forecast Discussion for Hawaii

Area Forecast Discussion   Issued: 05/06/2026 05:39:00 AM UTC

                        
137
FXHW60 PHFO 051939
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
939 AM HST Tue May 5 2026

.SYNOPSIS...
Light winds, increasing humidity, and land and sea breeze
conditions will persist through midweek as a series of fronts
pass north of the state. Showers will remain brief and primarily
over interior and leeward areas during the afternoons. Rainfall
chances may increase by the weekend as an upper disturbance
approaches the region.

&&

.SHORT TERM UPDATE...
Forecast remains on track as a developing trough near Oahu breaks
down the trade wind flow. The result is a transition to a
dominant land and sea breeze pattern, featuring increased clouds
and interior showers during the afternoon and evening hours.

Kilauea eruption episode 46 started earlier this morning. An
Ashfall Advisory has been issued to highlight the possibility of
tephra, ash, Peles hair and other lightweight pumice falling near
and downwind of the eruption. Due to the trade winds breaking
down and winds changing with height, material from the eruption
may fall to the north and northeast of Kilauea, possibly in the
Hilo area.

&&

.PREV DISCUSSION...
Issued at 339 AM HST Tue May 5 2026
The subtropical ridge will remain weak through midweek as a
series of cold fronts pass well north of the state. This pattern
has disrupted the typical trade wind flow, allowing land breezes
to develop overnight into this morning. A more humid air mass
will settle over the islands, with dewpoints climbing into the
upper 60s.

These elevated dewpoints, combined with a weak front in the
vicinity and afternoon sea breeze development, will support
localized cloud buildups and scattered showers over interior and
leeward areas each afternoon. Clearing is expected overnight as
land breezes reestablish.

By the latter part of the week into the weekend, moisture and
rainfall chances may increase. Global guidance indicates lowering
heights aloft as an upper-level disturbance and its attendant cold
front approach and move into the area. Uncertainty, however,
remains high due to differences in model solutions regarding the
timing and strength of these features, resulting in low confidence
in the details.

&&

.AVIATION...
Trades will continue to weaken over the coming days, resulting in
sites seeing more of a land/sea breeze pattern, especially by the
evening. In the meantime, showers lingering in the light ESE flow
can still impact windward areas. Afternoon showers over island
interiors are also possible. MVFR conditions are expected within
showers, and VFR will prevail elsewhere.

AIRMET Sierra is in effect for N through E sections of Oahu due to
lingering clouds and showers. This could be expanded to include
other islands later today due to potential cloud and showers
forming over island interiors.

Kilauea has recently erupted, prompting an initial SIGMET for
volcanic ash under series Victor. The plume is estimated to be
around 20kft, and will continue to grow in altitude. The ash
plume is forecasted to move N-NE of the volcano, and will continue
to be monitored for impacts near PHTO.

&&

.MARINE...
Issued at 339 AM HST Tue May 5 2026
The trades will ease and shift southeasterly at light to moderate
levels today and tonight as an approaching front merges with a
trough north of the island chain. The front will pass north of
the area on Wednesday, bringing light and variable winds, with sea
and land breezes present near the immediate coasts. A new high
building northwest of the state will bring a return of light to
moderate trades Thursday and Friday, with the trades strengthening
to moderate and fresh levels over the weekend. Winds and seas are
expected to remain below Small Craft Advisory thresholds through
at least Friday.

A moderate medium-period northwest swell will gradually lower
during the next couple of days. A new long period swell will build
Wednesday night and give a nice boost to north and west shore surf
Thursday and Friday, followed by a gradual decline over the
weekend into early next week.

A series of overlapping south swells will keep steady small surf
rolling into south facing shores during the next week.

Surf along east facing shores will remain below normal during the
next 7 days due to the lack of strong trades over and upstream of
the islands.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Ashfall Advisory until 8 PM HST this evening for Big Island East-
Big Island Southeast.

&&

$$

SHORT TERM UPDATE...Wroe
DISCUSSION...Gibbs
AVIATION...Trotter
MARINE...Jelsema