Waihee-Waiehu, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

306
FXHW60 PHFO 130118
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
318 PM HST Thu Jun 12 2025

.SYNOPSIS...
Breezy trades become strong this weekend into next week
delivering limited clouds and showers mainly to windward and mauka
areas.

&&

.DISCUSSION...

Closed mid-level low positioned west of the islands at press time is
transitioning to a weak and sheared out low amplitude shortwave as
it`s partially absorbed back into mid-latitude westerlies. This low
remains of little consequence other than the attendant subtropical
jet which is gracing area skies with occasional cirrus. Near the
surface, observed soundings indicate a very firm trade wind
inversion anchored near 6kft at Lihue and Hilo, though slightly
weaker in the vicinity of Kauai courtesy of closer proximity to the
low. This has kept a kept a lid on overnight showers while the
daytime diurnal max has maintained dry predominantly dry conditions
each afternoon. Little change expected going forward as showers
remain light and ridging north of the islands strengthens. This will
only reinforce stable trade wind conditions as trades become strong
this weekend into early next week. Given the strength of the
inversion and strengthening background trades, it will be worth
monitoring favored downslope areas for gusty wind potential as early
as Friday, mainly in Maui County and the Big Island.

Shear-induced upper low development is anticipated over the islands
this weekend which may diminish stability a bit, especially over the
western end of the state, but the shallow boundary layer moisture
field will likely be unable to capitalize leading to a rather
uniform scattered coverage of light-intensity showers each night.


&&

.AVIATION...
A stable, moderate to locally breezy trade wind flow will persist
through Friday, followed by an increase in winds during the
weekend. Periods of MVFR ceiling and visibility in SHRA will
focused along windward slopes, and during the overnight and early
morning hours AIRMET Sierra for mountain obscuration may be
needed. VFR will dominate over most leeward areas, but sheltered
terrain will experience isolated MVFR conditions each afternoon,
especially on the Kona slopes of the Big Island. The stable trade
wind flow will produce light turbulence below 7,000 feet, but
these conditions should not require AIRMET Tango through Friday.
An upper-level low to the west may produce some light turbulence
above FL300 into early Friday.


&&

.MARINE...

High pressure far northeast of the islands will remain nearly
stationary through the remainder of this week and bring moderate
to locally strong trade winds. High pressure will then re-center
north of the region this weekend and help to further strengthen
trades. Thus, a Small Craft Advisory for the windier waters and
channels around Maui County and the Big Island remains in effect
through at least Sunday.

Surf along south facing shores will be tiny to small over the
next several days. A small, long period, south swell originating
from a fetch near New Zealand will build late this weekend and
help to boost surf heights through early next week.

Rough and choppy surf is expected for east facing shores through
the forecast period due to the moderate trades. Tiny seasonal surf
is expected for North facing shores.


&&

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


&&

$$


DISCUSSION...JVC
AVIATION...Wroe
MARINE...Tsamous