Kaneohe Base, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

034
FXHW60 PHFO 260655
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
855 PM HST Mon May 25 2026

.SYNOPSIS...
A broad ridge of high pressure north of the Hawaiian Islands will
dominate our weather with continued moderate to locally strong
trade winds. An upper level trough east of the islands may help
enhance trade showers the next few days. A new mid week upper
level low moving in west of the islands may pass over the state
Friday into Saturday. This feature may enhance showers.

&&

.SHORT TERM UPDATE...
As mentioned in this afternoon`s discussion, trade magnitudes are
still up but more significant over the better exposed windward
locales and open waters. Overall, winds have noticeably fallen
off across many leeward communities. Today`s wind behavior of
sustained 15 to 20 mph with gusts to near 30 mph over windward
exposures...10 to 15 mph with gusts around 20 mph leeward...will
be the standard the next several days. Reasoning is that there
will be little change in the near 10 mb pressure gradient over
the islands from regenerative surface highs tracking east along
40N latitude through the remainder of the week. Rainfall will be
the typical summertime seasonal variety as pockets of moisture
riding in on the trades drop a few hundredths of an inch upon
their quick western passage (a wee bit more rain within higher
terrain). Fairly dry through Thursday with the wettest, more
cloudier days of the week occurring at it`s close. An upper level
low passing overhead Friday into Saturday will destabilize the
atmosphere just enough (cooling 5H from -5 C Tuesday to near -10 C
late Friday), in tandem with a band of slightly higher mid level
moisture passing in from the northeast, to garner a mention of
more inclement late week weather.

&&

.PREV DISCUSSION...
Issued at 338 PM HST Mon May 25 2026
There has been some further tweaks to the winds for the week to
bring them in better alignment with the latest model runs, that
suggest winds will remain a touch stronger than previously
anticipated. Otherwise the forecast remains the same as the update
issued earlier today.

Satellite shows some showery clouds riding in on the trade wind
flow. A ridge far north of the islands will remain in place into
the middle of the week, with the pressure gradient over the
islands steady. As mentioned this morning, some of the high
resolution models would suggest some areas could reach advisory
levels winds in the next couple of days, but continue to feel
this is not representative of overall conditions.

The afternoon sounding from Hilo The overnight 12Z sounding from
Hilo showed a fairly strong temperature inversion around 7,500
feet, while the Lihue sounding had a weaker inversion around 6,000
feet.

High pressure at the surface will linger through the
week, with some weakening of the pressure gradient over the
islands during the second half of the week. An upper level low
has formed about 900 miles to the northwest of Kauai, and is
expected to move towards the islands this week. The global models
suggest that this could help to enhance trade wind showers at the
end of the week. At this time, the global model thunderstorm
probabilities are not impressive. Additionally, near normal 500
and 700 mb temperatures are expected in the global models. The GFS
brings in higher precipitable water than the ECMWF near Maui
County and the Big Island for the upcoming weekend. At this time
it would seem the upper low/trough could enhance trade winds, but
not expecting much beyond that based on the current model runs.

&&

.AVIATION...
Issued at 338 PM HST Mon May 25 2026

Moderate to breezy trades will continue for the next few days.
Low cigs and SHRA possible over windward and mauka locations. MVFR
conditions possible in SHRA, otherwise VFR prevails.

AIRMET Tango remains in effect for mod low-level turbulence over
and downwind of terrain across all islands.

&&

.MARINE...
Issued at 338 PM HST Mon May 25 2026

Fresh to strong easterly trades will persist through the first
half of the week as a strong surface ridge remains north of the
state. This will allow the Small Craft Advisory to continue across
most Hawaiian coastal waters through midweek. Expect a gradual
downward trend through the second half of the week and into next
weekend due to a weakness forming in the ridge as a front passes
far to the north.

Surf along south-facing shores will gradually lower tonight as a
lingering medium-period south swell fades. A fresh long-period
south swell will arrive Tuesday, then build to near the seasonal
average through midweek before slowly easing Thursday. A more
significant long-period south-southwest swell is expected by next
weekend due to a storm-force low that passed southeast of New
Zealand over the weekend. Satellite data showed a large fetch of
40 to 50 kt winds generating seas of 35 to just over 40 ft,
focused toward, or just east of Hawaii along the 190-degree
directional band. Expect surf to begin building locally Friday
with 20+ second forerunners, then peak above/around the advisory
level over the weekend. For the long range, expect a similar trend
to persist through the first week of June as the active pattern
persists within our swell window around New Zealand.

Surf along exposed north- and west-facing shores will also
continue to lower tonight as a small lingering north-northwest
swell fades, but will trend up once again on Tuesday as the late
season North Pacific activity continues. Although the bulk of the
energy from this next swell will be focused northeast of the
islands, expect long-period forerunners to arrive Tuesday, then
fill in down the island chain through midweek. Above-average surf
is likely by daybreak Wednesday near the peak before lowering
Thursday.

Surf along east facing shores will remain rough through midweek,
then gradually lower later in the week as the trades ease.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 AM HST Wednesday for Alenuihaha
Channel-Big Island Leeward Waters-Big Island Southeast Waters-
Big Island Windward Waters-Kaiwi Channel-Kauai Channel-Kauai
Leeward Waters-Kauai Northwest Waters-Kauai Windward Waters-
Maalaea Bay-Maui County Leeward Waters-Maui County Windward
Waters-Oahu Leeward Waters-Oahu Windward Waters-Pailolo Channel.


&&

$$

SHORT TERM UPDATE...Blood
PREV DISCUSSION...M Ballard
AVIATION...Evans
MARINE...Farris