771
FXHW60 PHFO 050157
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
357 PM HST Tue Jun 4 2024

.SYNOPSIS...
Breezy trades will gradually ease over the next few days with
light trades expected by Thursday. Trades should be light enough
for daytime sea breezes across select areas on Thursday. A slight
strengthening of the trades is expected Friday into the weekend.
Otherwise, very dry conditions will overspread the entire island
chain Thursday through the weekend, greatly limiting shower activity.
Breezy trades returning early next week should bring the return
of some windward showers.

&&

.DISCUSSION...
This afternoon`s satellite imagery shows stable stratocumulus
clouds anchored over select windward areas. Although we do have
some decent amount of cloud cover in select areas, it has been a
fairly dry day today with all of our rain gauges reporting less
than 0.05 inches during the past 6 hours. Latest water vapor
imagery shows a upper level trough just north of the Big Island
drifting northeast. This trough could provide enough instability
for some isolated thunderstorms over on the Kona slopes of the Big
Island through this evening. This upper level trough should
gradually move northeast and away from the state over the next 24
hours.

Trades are expected to weaken another notch on Wednesday as the
ridge of high pressure north of the state drifts closer to the
state. By Thursday, the ridge of high pressure will be very close
to the state and we should the winds weaken another notch. Latest
ECMWF and NBM models are in good agreement with a light trade wind
pattern for Thursday, while the GFS remains the outlier with the
ridge very close to the state and a very light wind pattern. The
latest wind forecast has been updated to show winds closer to
consensus. Although the trades will likely still be light enough
for sea breezes to develop during the day time. From Friday into
Saturday, winds will likely pick up a touch and we should see a
light to moderate trade wind pattern.

As far as precipitation, there will be little of it through the
weekend. The Kona slopes should have a chance for showers each
afternoon, but as a drier and very stable air mass moves in over
the next few days, any shower activity will remain light.
Elsewhere, with a strong mid level ridge overhead and drier than
normal low level moisture, clouds will still develop, but very
little vertical development is expected of the clouds. Thus,
little to no precipitation is expected through the weekend.



&&

.AVIATION...
Breezy easterly trades will continue through this evening, then
gradually weaken into tomorrow as the pressure gradient relaxes.
Clouds and showers will favor windward and mauka locations with
periods of MVFR conditions possible. Otherwise, VFR conditions
will generally prevail. Lingering elevated atmospheric instability
over the state will allow for the potential development of
isolated thunderstorms over interior and upslope sections of the
Big Island through this evening. Stability will increase heading
into Wednesday as mid level ridging strengthens over the state,
ending the thunderstorm potential.

AIRMET Tango for low level turbulence lee of island terrain
remains in effect. This AIRMET will be needed through this
evening, but will likely be cancelled by Wednesday morning as
winds below the inversion decrease.

AIRMET Sierra remains in effect for mountain obscuration for
windward sections of the smaller islands. This AIRMET may need to
be extended through mid to late morning tomorrow before
conditions improve into the afternoon, and windward portions of
the Big Island may need to be included.


&&

.MARINE...
A ridge of high pressure along 30N continues to bring trades to
the region. The ridge is sinking southward, and the result is a
downward trend to the winds. The Small Craft Advisory (SCA) has
been scaled back to the typical windier waters around the Big
Island and Maui County for tonight. Winds are expected to
weaken further tonight, and fall below SCA levels by morning. Over
the weekend, the ridge is expected to lift northward, allowing
moderate trades to return from south to north.

The active south Pacific will continue to generate southerly
swells that will pass through the islands through the middle of
the month. The current south-southwest swell has started to
decline, and a continued gradual decline is expected through
Thursday. Another reinforcing south-southwest swell is expected to
arrive late Thursday and Friday, that is currently expected to
bring south facing shore surf around the seasonal average. A
larger swell is expected to move through the islands this coming
weekend, which will likely be near or at HSA levels of 10 feet. An
potentially even larger swell is looking increasingly likely late
next week that would bring surf well above advisory levels.

The current small northwest swell will get a reinforcement from
the northwest will follow Wednesday into Thursday. The fresh to
strong trade wind flow is producing rough choppy elevated seas but
the wind waves will diminish significantly after Wednesday
coinciding with the light winds through the weekend.


&&

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


&&

$$


DISCUSSION...Kino
AVIATION...Farris
MARINE...M Ballard