Waihee-Waiehu, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

781
FXHW60 PHFO 160114
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
314 PM HST Thu May 15 2025

.SYNOPSIS...
Moderate to locally breezy easterly trade winds will prevail
through the week. A disturbance aloft will linger near the state
and enhance moisture in the trade wind flow. Showers will be
active across windward slopes and will periodically pass over
leeward areas, especially at night. Leeward Big Island will
experience spotty showers, some heavy, each afternoon.

&&

.DISCUSSION...
A breezy and slightly unstable trade wind flow will prevail
during the next few days. A robust 1031 mb surface high
meandering about 1200 to 1300 miles northeast of the state will
maintain easterly trades near current strength, though a shift out
of the east-southeast is expected during the weekend as troughing
develops far northwest of the islands. The inversion is elevated
and weak at around 9,000 feet this afternoon due to an upper-level
low parked over the region. This feature should deepen slightly
Friday and Saturday, leading to modest instability. The
instability will enhance pockets of moisture moving within the
trade wind flow, causing showers along windward areas to be more
frequent and briefly heavy. One such area of moisture will move
through on Friday and allow some showers to periodically pass over
leeward areas from Kauai to west Maui. On leeward Big Island,
typical spotty afternoon showers will be briefly heavy with a
slight chance of thunderstorms each afternoon.

Moderate to locally breezy trade winds will shift back out of the
east-northeast on Monday as surface high pressure becomes
established far north of the islands. The upper-level trough is
expected to drift just northeast of the state through at least
Wednesday. This subtle shift is expected to be enough to lessen
the chances of thunderstorms, though the inversion may remain
slightly weak and elevated. As a result, expect showers along
windward areas to continue to be more active than usual.

&&

.AVIATION...
Moderate to breezy trade winds continue across the island chain
through Friday afternoon, steered by high pressure centered far
northeast of the main Hawaiian Islands. Passing showers and
occasional low clouds embedded within the trades will favor north
through southeast sections of the islands throughout this period,
especially during the overnight to early morning hours. While VFR
flight conditions will prevail at most locations, periods of MVFR
conditions will be possible within any showers that occur.

AIRMET SIERRA is in effect for mountain obscurations for windward
sections of most of the islands. Passing showers will continue to
produce periods of MVFR conditions across windward areas through
Friday. AIRMET Tango remains in effect for moderate low-level
turbulence over and downwind of island terrain. This AIRMET will
likely also continue through Friday.

&&

.MARINE...
An area of strong high pressure will remain nearly stationary far
northeast of the state through the rest of the week, bringing
fresh to locally strong trade winds to the coastal waters. A Small
Craft Advisory (SCA) remains in effect for the windier waters
around Maui County and the Big Island through Friday for now.
While winds may ease slightly and veer toward the east-southeast
this weekend due to a trough far northwest of the state, the SCA
will likely need to be extended for at least some zones into next
week.

Surf along north and west-facing shores will remain small for the
next few days. Only a slight bump in north shore surf is possible
on Friday and Saturday due to small medium-period northwest
energy moving through the region. Surf along south-facing shores
will also remain small throughout the next week. A tiny long-
period south-southwest swell will build late Friday into the
weekend. Otherwise, expect mainly background energy through at
least the middle of next week.

Surf along east-facing shores will remain rough and choppy the
next several days due to the fresh to locally strong trades.

&&

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

&&

$$

DISCUSSION...Wroe
AVIATION...Kino
MARINE...Vaughan