Drought in Hawaii, November 1 to 30, 2025

Area Forecast Discussion
National Weather Service Honolulu HI
343 PM HST Fri Oct 31 2025

.SYNOPSIS...
Moderate trade winds will continue through Saturday, with stable
conditions and showers focusing along windward and mauka
locations. During the second half of the weekend, trades will
weaken in response to an approaching frontal boundary and upper-
level low advancing southward near the western end of the state.
This will bring unsettled weather, particularly for Kauai, Sunday
into Monday. Drier conditions are expected through much of the
remainder of next week as high pressure becomes reestablished
north of the islands.

&&

.DISCUSSION...
Moderate trade winds are prevailing across the island chain
today, driven by surface high pressure centered far northeast of
the state. Showers and low clouds have been relatively minimal
today, primarily favoring windward and mauka areas and the Kona
slopes of the Big Island this afternoon. To our north, latest
surface analysis shows a pair of cold fronts in the vicinity of
30N.

For tonight through Saturday, generally stable conditions are
expected, with moderate trades and limited shower activity, other
than a few passing showers for the typical windward and mauka
areas. Skies will remain mostly clear over leeward and interior
areas.

Trades will gradually weaken in response to an advancing frontal
boundary, shifting out of the southeast near Big Island and Maui,
and northeast near Kauai and Oahu Saturday night into Sunday. The
front will approach and is expected to reach Kauai late Sunday
evening before meandering away from the islands. This boundary
will have excess moisture escorted in with it, resulting in
increased shower chances, primarily across the western islands.

Immediately behind the frontal boundary, guidance continues to
show a low aloft breaking away from upper troughing and drifting
south southwest near the western end of the state on
Sunday. Southerly flow aloft will draw even more tropical
moisture northward across the islands. As previous discussions
have mentioned, the heaviest showers associated with this feature
are expected to focus over or near Kauai late Sunday into Monday.
It should be noted, however, that there remains a great deal of
uncertainty regarding the exact placement of the upper low and the
associated moisture. Latest ensemble guidance is depicting
rainfall amounts lower than the previous forecast. Based on the
ensemble guidance, and on the latest NBM Probabilistic
Quantitative Precipitation Forecast (PQPF) percentiles, QPF was
lowered a bit with this afternoon's forecast updates. However,
hesitant to lower it too much at this point given the remaining
uncertainty, so the official forecast still remains roughly
similar to the 90th percentile of the NBM for now. Additionally,
with 500mb temperatures cooling to near -10C to -11C in guidance,
have introduced isolated thunder chances for Sunday for Kauai and
Niihau and surrounding coastal waters.

High pressure is expected to rebuild into the region from Tuesday
through Thursday, allowing trades to become reestablished across
the region. With drier air working into the region and stable
conditions returning, showers will once again be confined to
mainly windward and mauka areas.

&&

.AVIATION...
Moderate trade winds will continue through tomorrow across the
state. Embedded showers within the trade winds will bring periods
of MVFR conditions over windward slopes. Otherwise, VFR
conditions will prevail.

AIRMET Tango is in effect for TEMPO moderate turbulence between
FL300 and FL450, from Molokai to the Big Island. The turbulence
is expected to weaken this evening, and is not likely to persist
through tonight.

&&

.MARINE...
High pressure to the northeast will maintain moderate to locally
fresh trade winds through tonight. A Small Craft Advisory (SCA)
is in place over typical windy areas around the Big island and
Maui through tonight. Winds will decrease Saturday as a front
currently to the northwest of the islands moves southeast towards
the region and displaces the ridge. Isolated thunderstorms will be
possible for the northwestern coastal waters by Sunday as the
front approaches the western end of the state. The front is
expected to stall and then get pushed to the west as high pressure
builds back in by Monday. Resulting easterly trade winds should
remain moderate this weekend until Monday where trade winds are
forecast to increase to the moderate to fresh range. Winds are
expected to remain below SCA levels until Tuesday or Wednesday.

The approaching front is expected to enter the offshore waters
Saturday, with the possibility of gale force winds over the
extreme northwest portion of the offshore waters Saturday night
and Sunday. The front will also bring the possibility of
thunderstorms to the offshore waters.

Surf is expected to increase tonight in response to a long period
NNW swell (330) with surf peaking at High Surf Advisory (HSA)
levels late Saturday morning. Surf will hold at advisory levels
through Saturday night, and a High surf advisory is in place for
that time frame for N and W facing shores. A short period NNE
swell, associated with an approaching front with gale winds, is
expected to arrive Sunday, and primarily impact the surf at the
western end of the state where it will mix with the longer period
NNW swell. This boost will likely bring HSA level surf back to
Kauai and Oahu by Sunday afternoon and will gradually fade out
next week. A moderate to large swell is then possible around the
middle of next week.

Surf along east facing shores will remain small to moderate through
Saturday, and then be impacted by the short period NNE swell mentioned
above. South shore surf will decrease tonight and remain small
through the weekend.

&&

.FIRE WEATHER...

Increased relative humidity values and decreasing trade wind
speeds will keep fire weather conditions below critical
thresholds into next week.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory from noon Saturday to 6 AM HST Sunday for
north and west facing shores of Niihau, Kauai, Oahu, Molokai, and
north facing shores of Maui.

Small Craft Advisory until 6 AM HST Saturday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.

&&

DISCUSSION...Vaughan
AVIATION...DT
MARINE...Tsamous
FIRE WEATHER...Vaughan