647
FXHW60 PHFO 051905
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
905 AM HST Wed Jun 5 2024

.SYNOPSIS...
Trade winds will diminish as dry and stable conditions build over
the area and a land and sea breeze pattern emerges for the
remainder of the week.

&&

.DISCUSSION...

Morning satellite and radar imagery shows flat, textureless clouds
off the windward coasts and virtually nil shower activity. A sharp
trade wind inversion is noted on this morning`s Hilo sounding, a
consequence of transient shortwave ridging building in from the
northwest and dry advection aloft coming from the east. By tomorrow,
this transient ridging will be replaced by stronger and broader
ridging that is currently building eastward across the Central
Pacific. This will set the stage for increasingly stable and dry
conditions persisting into next week. This period of ridging will
also force the trade wind belt to weaken and migrate south of the
islands leading to warmer weather and an expansion of sea breezes
for coastal areas.
&&

.AVIATION...

Trade winds will gradually weaken through tomorrow as the
pressure gradient over the Islands relaxes, with moderate to
breezy winds expected today and light to moderate winds expected
on Thursday. Bands of clouds and light showers will favor east and
northeast facing slopes and coasts today as they ride in on the
trades. Brief MVFR conditions will be possible with these low
clouds and light showers, otherwise VFR conditions will prevail
statewide. On Thursday, lighter winds will allow for land and sea
breeze development and drier air will filter in...allowing for
less overall low to mid level cloud cover and very limited light
shower activity.

Though weaker than yesterday, lingering mid-level atmospheric
instability will encourage convective showers over interior and
upslope portions of the Big Island this afternoon and early
evening. Stability is expected to increase later in the week as
mid level ridging builds over the state.

AIRMET Sierra remains in effect for mountain obscuration for
windward sections of Oahu and Kauai. Conditions are expected to
improve by later this morning. However, satellite shows a rather
robust stratocumulus deck moving in on the trades, so we will
continue to monitor.
&&

.MARINE...

A ridge of high pressure to the island is slowly sinking
southward, weakening the trade winds over the region. Expect winds
to remain below Small Craft Advisory (SCA) levels through the end
of the week. Over the weekend, the ridge will lift to the north,
allowing moderate trade winds to return from south to north.

A series of low pressure systems in the far south Pacific will
continue to generate swells that will pass through the islands
over the next week or so. The current south-southwest swell has
started to decline, with a gradual decline expected to continue
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. Another swell is expect to arrive this coming weekend, which
will could bring surf near High Surf Advisory levels. Yet another
swell is expected to arrive late next week that would once again
bring surf at or above advisory levels.

The current small northwest swell is on the decline as shorter
period energy is now moving through the islands. Another small pulse
from the northwest is expected to build through the day into
Thursday keeping surf elevated. Wind waves for east facing
shores will decline today and will diminish significantly after
today coinciding with the light winds through the weekend.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$


DISCUSSION...JVC
AVIATION...Farris
MARINE...M Ballard