Drought in Hawaii, April 1 to 19, 2022

Area Forecast Discussion
National Weather Service Honolulu HI
830 PM HST Thu Mar 31 2022

.SYNOPSIS...
Breezy trade winds will increase over the next couple of days and
become gusty through the weekend. Showers will favor windward
slopes and, aside from afternoon showers over the Kona slopes of
the Big Island, leeward areas should see little rainfall.
Increasing moisture could enhance shower coverage early next week
as an upper disturbance moves into the area.

&&

.DISCUSSION...
Trade winds continue to strengthen this evening. A high located
far northwest of the state is driving the resurgent trade winds,
though the local pressure gradient continues to be slightly
weakened by a stalled front north of Kauai. Upper ridging keeps
our airmass neutral to stable. A diffuse pocket of moisture moving
along the trade wind flow is producing moderate showers along
windward slopes of all islands and, aside from isolated heavy
showers over leeward Big Island, leeward areas will continue to
see brief passing showers through the evening.

Trade winds will ramp up on Friday and will be breezy and gusty
through the weekend as the high moves north of the state. Upper
ridging will maintain somewhat stable conditions, but it should
not be strong enough to produce a firm low level inversion. As a
result, the gusty trades may fall short of Wind Advisory strength,
and a few showers will likely be carried over to leeward areas
from Maui to Kauai at times.

Trade winds will decrease and shower chances may increase during
the first half of next week. Trades will ease as the high is
weakened and displaced eastward by a front. The upper ridge will
be eroded by a deepening upper trough, leading to some
instability. The initial result will be thickening high clouds on
Monday and, as the upper trough moves overhead on Tuesday, deeper
low level moisture being drawn up from the south could increase
shower activity.

&&

.AVIATION...
With robust high pressure centered far north of the islands, trade
winds will be breezy to locally strong. Showers, with accompanying
MVFR ceilings and visibilities, will mainly affect windward and
mauka sections, though occasionally spreading leeward with the
gusty trades.

An AIRMET for low level turbulence to the lee of the islands
remains posted and will likely be extended at least through
Friday night. Another AIRMET has been issued for TEMPO mountain
obscuration for Oahu through Maui as showery low clouds move over
the isles riding on the trades.

&&

.MARINE...
A surface high pressure system centered far north-northwest of
the islands is moving slowly east through Friday. This will
produce locally strong trade winds through Friday afternoon.
Therefore, a Small Craft Advisory (SCA) remains in effect for the
typically windier waters adjacent to the is;ands of Maui County
and the Big Island. By late Friday, the surface high is expected
to be far north of the state, which will cause additional
strengthening of the trade winds, with winds likely peaking near
gale force in the windier channels. In addition, combined seas
will become elevated and rough over areas exposed to the strong
trades. Therefore, expect the SCA to be expanded to include all
Hawaiian waters from late Friday through most of this weekend.
The surface high will eventually weaken northeast of the islands
early next week, which will cause the trade winds to ease next
Monday and Tuesday.

A new, long-period northwest swell arriving early Friday will
build through Friday afternoon, and then will peak from Friday
night into Saturday. Surf will likely be near the High Surf
Advisory criteria along exposed north and west facing shores of
the smaller islands when it peaks. This swell will then gradually
lower from Saturday night through early next week. Small
background northwest swells will continue to produce small surf
along most north and west facing shores during the middle of next
week.

The strengthening trade winds will cause surf to build along east
facing shores, and it will become elevated and rough this
weekend. The weakening trade winds will cause the surf to lower
along east facing shores early next week. Background south swell
energy will maintain small. nearly seasonal background surf along
most south facing shores. Note that the trade wind wrap may
produce slightly elevated surf along some shorelines with an east
exposure, such as the southeast Big Island.

&&

.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...Powell
AVIATION...Kinel
MARINE...Houston