Ewa Gentry, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

855
FXHW60 PHFO 060124
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
324 PM HST Thu Jun 5 2025

.SYNOPSIS...
High pressure far to the northeast of the islands will weaken over
the next few days. Breezy trades will become gentle to locally
breezy as we head into the weekend. A trough developing west of
the islands early next week should keep winds gentle to locally
breezy, but the flow will turn toward the east-southeast. Fairly
typical night and morning trade wind showers are expected. A few
more interior afternoon showers are possible early next week as
well.

&&

.DISCUSSION...
A relatively strong and large surface high, about 1034 mb, is
nearly stationary about 1600 mi to the NE PHNL, driving breezy
trade winds over our islands again today. The high is a few mb
weaker than yesterday and thus our trades are just a notch
slower. A band of showers on the trades moved through late last
night and this morning and has cleared the islands, leaving us a
somewhat drier airmass with fewer showers upstream. Both 00z
soundings showed an inversion near 7800 feet, and PW just
slightly above normal.

Mainly subtle summertime changes expected through the forecast
period over the main Hawaiian Islands, and models are in good
agreement. The high far to the NE will weaken as a wavy front
stalls far to the N of the islands. This will weaken the local
pressure gradient a bit, so trades will drop to background gentle
speeds, only locally breezy in the typical windier areas by Fri.
Trades will then continue at those speeds through the weekend.
Starting about Mon, a surface trough will develop out near 170w
near Lisianski and Laysan Islands, and this will turn our local
background flow over the main Hawaiian Islands to the ESE. It will
still be locally breezy, but many areas will be shadowed from the
background winds by island terrain. The surface trough will move
away to the NW by the middle of next week, and a new large surface
high will build far to the NE of the islands once again,
returning us to breezy trades by Thu.

As far as the sensible wx goes, a fairly typical pattern of
summertime trade wind showers is expected for the next few days as
modest mid-level troughing develops over the islands, and moisture
levels remains fairly close to climatology for June. Light to
moderate showers will favor windward and mauka sections during the
nights and mornings. For Mon and Tue, we look to get into a
hybrid pattern of windward and mauka showers favoring nights and
mornings. There will also be a small chance for a couple of
afternoon interior or leeward showers as well, as low level
moisture ticks up a bit to slightly above climo. Depending on how
much the background flow veers, it`s possible portions of the
smaller islands, like the south shore of Oahu, could even see a
few showers developing in the convergence downwind of Maui County
in the ESE flow, but much too early to include this explicitly in
the forecast right now. A more typical trade wind shower
distribution returns on Wed as low level moisture decreases
slightly once again.

&&

.AVIATION...
Moderate to locally breezy trades will persist through the
evening, then gradually ease into Friday as the surface ridge to
the far northeast of the state weakens. Batches of moisture riding
in on the trades will deliver brief showers to windward and mauka
areas through the period. MVFR conditions will be possible in
showers. Otherwise, VFR conditions will prevail.

AIRMET Tango is now in effect for moderate turbulence between
15,000 feet and 36,000 feet due to a jet streak on the eastern
side of the base of an upper level trough moving overhead. This
AIRMET will likely be needed overnight and into tomorrow morning.

AIRMET Tango remains in effect for low level moderate turbulence
over and immediately south through west of island mountains due to
moderate to breezy trade winds. This AIRMET will likely be
cancelled later this afternoon or overnight as the trade wind
speeds decrease.

&&

.MARINE...
Moderate to locally strong trades will gradually ease tonight,
becoming gentle to fresh by Friday in response to weakening high
pressure northeast of the state. Gentle to fresh trades prevail
Friday into early next week then restrengthen as the seasonal high
redevelops. Additionally, winds could veer slightly east-
southeast early next week in response to a potential surface
trough developing west of the islands. Small Craft Advisory is in
effect through 6 am Friday as locally strong winds hold through
the afternoon and into the evening hours.

Tiny to small, long period southwest swell will hold this
afternoon maintaining small surf along favored exposures.
Forerunners from a moderate, long period south southwest swell
originating from an extratropical cyclone east of New Zealand will
gradually fill in tonight into Friday. This swell will peak over
the weekend near or above the High Surf Advisory threshold before
slowly fading early next week.

Choppy surf along east facing shores will hold into the weekend
even though locally induced tradewind swell will be on the
decline. This is thanks to a low that developed near the
California coast earlier this week which is sending a moderate,
medium period northeast swell later today and should peak Friday
before fading Saturday. Surf along north facing shores will remain
small however could see some minor northeast wrap tonight into
Friday before returning to near flat Friday night through the
weekend.

&&

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

&&

$$

DISCUSSION...R Ballard
AVIATION...Farris
MARINE...Tsamous