Area Forecast Discussion for Hawaii

Area Forecast Discussion   Issued: 11/06/2026 04:37:00 PM UTC

                        
805
FXHW60 PHFO 060637
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
837 PM HST Thu Nov 5 2026

.SYNOPSIS...
A weak upper low combined with a tropical wave passing south of
the islands will ramp up humidity levels and keep periods of wet
weather in the forecast through Friday. Drier trends are forecast
for the weekend.

&&

.SHORT TERM UPDATE...
The latest satellite imagery this evening shows an area of
thunderstorms near a tropical disturbance roughly 800 miles
southeast of the Big Island, and a weakening cold front roughly
650 miles northwest of Kauai continues to slowly approach the
islands. Water vapor imagery shows a weak upper low just west of
the islands, spreading divergent high level cirrus clouds across
the state. This upper low will in the short term continue to
weaken and lift the trade wind temperature inversion, allowing for
continued periods of passing showers.

A tropical wave passing south of the islands will ramp up humidity
levels across the state and keep periods of wet weather in the
forecast for Friday. Drier trends are forecast for the weekend.

A few updates to the forecast grids this evening. Lowered
sustained wind speeds over Oahu and Molokai for the next few days.
Removed isolated thunderstorms for the Big Island tonight as there
will likely not be a sufficient trigger for thunderstorm development.

&&

.PREV DISCUSSION...
Issued at 351 PM HST Thu Nov 5 2026

The 18Z surface analysis shows a ridge of high pressure north of
the state driving breezy trades across the island chain this
afternoon and a trough to the southeast of the Big Island. Radar
imagery shows isolated light to moderate showers in windward
areas.

The tropical disturbance southeast of the islands remains an
elongated trough for the time being. The latest ASCAT pass from
1928Z indicates winds remain less than 25 kts north of 20N
latitude, which is a reduction from the last couple passes. While
some uptick in winds is likely near the typically favored terrain
features this evening, confidence for a larger scale increase of
wind has decreased. Therefore, held off on Wind Advisories for
now.

Satellite derived pwats from CIMSS depicts deeper moisture
approaching the Big Island from the southeast late this afternoon.
By late tonight and Friday, pwats should exceed 2 inches across
the Big Island. A sharp uptick in shower development is expected
in windward and mauka areas, possibly leeward as well. Isolated
thunderstorms capable of producing heavy downpours cannot be
ruled out for Big Island through Friday as the deep moisture erodes
inversion heights, allowing for some terrain induced convection
to occur. Total rainfall totals of 2 to 3 inches appear likely for
windward Big Island with some areas possibly approaching 4.

After the system passes west of the state Saturday into Sunday, a
much drier airmass and lower inversion heights will filter in
from the east into next week. Winds will ease to more typical
levels. The drier airmass and lower inversion heights will also
limit shower coverage to mainly windward areas.

&&

.AVIATION...
Issued at 351 PM HST Thu Nov 5 2026
Breezy trades will continue for the next few days. An area of
enhanced moisture moving in from the east will affect windward
portions of the Big Island and to a lesser extent, the rest of the
islands tonight into tomorrow morning, bringing more widespread
MVFR with pockets of IFR for windward areas. Isolated showers with
brief MVFR conditions could also spill over to leeward areas,
mostly during the evening and early morning hours.

AIRMET Sierra is in effect for mtn obsc for windward portions of
Kauai and Oahu due to persistent showers. Conds should become
worse later tonight as more moisture moves in and the AIRMET could
expand to include more islands.

AIRMET Tango remains in effect for mod turb lee of terrain and
should remain in effect for next few days.

&&

.MARINE...
Issued at 351 PM HST Thu Nov 5 2026
Fresh to strong trade winds with periods of near gales will
prevail through the weekend as high pressure persists north of the
state. A Small Craft Advisory (SCA) remains in place for all
Hawaiian Waters for a combination of winds and elevated seas. The
SCA was extended through Saturday night and will likely remain in
place through at least Sunday night as a disturbance or tropical
cyclone passing a couple hundred miles to the south keeps the
local pressure gradient tight. Winds are expected to ease slightly
as the ridge to our north erodes and the potential tropical
cyclone moves away to the southwest. The SCA will likely be
trimmed back to the typical windy waters around Big Island and
Maui sometime Monday or Tuesday.

A long-period north-northwest (325 to 345 degree) swell will peak
through evening and produce surf well above High Surf Advisory
thresholds along exposed north and west facing shores from Kauai
to Maui. Recent observations from NOAA buoy 51001 northwest of
Kauai showed the swell at around 9 feet at 16 seconds, and swell
energy at the PacIOOS Waimea buoy continues to slowly rise this
afternoon. Surf will decline below advisory thresholds late Friday
as the north-northwest swell declines. Reinforcing medium period
energy out of the north-northwest (330 to 340 degree) should
arrive late Saturday into Sunday. Surf could approach advisory
thresholds during its peak early Sunday morning. Another large
northwest to north-northwest swell is Wednesday or Thursday of
next week.

A small south-southwest swell is expected to fill in overnight.
This small bump should peak Friday with waves slightly above
average for this time of year Friday into Saturday along south
facing shores. Surf along east-facing shores will stay elevated
and choppy through much of the week due to the strong trades.
Select northeast exposures should see long-period energy from the
large north-northwest swell today through tonight.

&&

.FIRE WEATHER...
Issued at 351 PM HST Thu Nov 5 2026

Persistent rainfall will continue to limit the widespread
availability of receptive fuels. Breezy and gusty winds will
continue during the next several days, generating moderate fire
weather conditions. Isolated thunderstorms will be possible for
Big Island tonight through Friday. The inversion near Big Island
will range from 8000 to 10000 ft through Friday.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory until 6 PM HST Friday for north and west facing
shores.

Small Craft Advisory until 6 AM HST Sunday for all Hawaiian
coastal waters and channels.

&&

$$

SHORT TERM UPDATE...Bohlin
PREVIOUS DISCUSSION...Borghoff
AVIATION...Tsamous
MARINE...Wroe
FIRE WEATHER...Borghoff