Halawa, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

040
FXHW60 PHFO 200441 AAA
AFDHFO

Area Forecast Discussion...UPDATED
National Weather Service Honolulu HI
641 PM HST Thu Jun 19 2025

.SYNOPSIS...
High pressure far northeast of the state will remain in place
through the next few days. Showers will favor windward and
mountain areas, especially during the overnight through early
morning hours. This weekend, trades will increase and much drier
air will move into the region. Shower trends will increase again
from Monday onward as trades return to the moderate to locally
breezy range.

&&

.DISCUSSION...
Moderate to locally breezy easterly trade winds are prevailing
across the main Hawaiian Islands this afternoon, steered by high
pressure that remains nearly stationary far northeast of the
state. Embedded within these trades are isolated to widely
scattered showers, though observations from rain gauge networks
across the state show that rainfall amounts have been minimal.
Daytime convergence has also increased cloud cover and produced
isolated showers across the Kona slopes of the Big Island since
late morning. Meanwhile, the latest upper air soundings from Hilo
and Lihue show stable conditions with strong inversions between
about 5,000 and 6,500 feet and less available low-level moisture
when compared to this same time yesterday afternoon.

A low level trough east of the islands will continue to drift
westward towards the state, passing over the islands tonight
through Friday. This trough is expected to briefly increase
inversion heights, producing deeper clouds and increasing shower
trends, especially over the western islands through Friday.
However, overall rainfall amounts are expected to remain limited.
The best chances for showers through Friday will remain across
windward and mountain areas, especially during the overnight
through early morning hours.

This weekend, however, a much drier air mass will be ushered into
the region as the high pressure to the northeast strengthens. As
the previous discussion mentioned, temperature inversion heights
may drop into the 4,000 to 5,000 ft range this weekend, increasing
wind speeds and limiting cloud and shower development. Much lower
humidity levels due to the drier air mass and locally windy trade
winds will elevate fire concerns across the state on Sunday. Some
tweaks have been made to winds on Friday and Saturday with this
afternoon`s forecast updates, but the overall forecast philosophy
remains in tact.

From Monday onward, expect a subtle increase in shower trends to
return to the islands as a combination of troughing aloft moves
over the region. Trades will also return to the moderate to
locally breezy range early next week.

&&

.AVIATION...
Moderate to locally breezy trades will continue through Friday.
Showers will favor windward and mauka areas, with a slight uptick
during the overnight and early morning hours. Expect mainly VFR,
with brief MVFR under passing showers.

AIRMET Sierra for mountain obscurations remains in effect for
windward sections of Oahu and the Big Island. Conditions should
improve later tonight as drier air starts to move in.

&&

.MARINE...
High pressure north of Hawaii will slowly move eastward and drive
moderate to locally strong trades across the local waters for the
next couple of days. The Small Craft Advisory (SCA) for typically
windier waters and channels near Maui and the Big Island has been
extended through Saturday afternoon. Trade winds are forecast to
increase further this weekend as the high strengthens, with
potentially more widespread SCA conditions later this weekend into
early next week. Trade wind speeds could then decrease slightly
by middle of next week.

A small, long-period, south swell will gradually drop Friday into
the weekend, with south shore surf slowly dropping as well. Back
to back pulses of slightly larger south swells are possible starting
Monday which could build surf near to above advisory levels (10
ft) along south facing shores as early as Monday night into
Tuesday,then remain near to above average through much of next
week.

Rough and choppy conditions will continue along east facing shores
and may pick up further into early next week as winds strengthen.
Surf will remain nearly flat along north facing shores.

&&

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

&&

$$

DISCUSSION...Vaughan
AVIATION...Ahue
MARINE...TS