246
FXHW60 PHFO 160644
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
844 PM HST Mon Jul 15 2024

.SYNOPSIS...
Breezy trade winds will ease to moderate strength Wednesday
through Friday as broad high pressure weakens northeast of the
state. Stable and somewhat dry conditions will prevail through at
least Friday, with light showers favoring windward slopes.


&&

.DISCUSSION...
No changes to the forecast this evening. A broad high pressure
system remains along 35N, driving locally breezy trade winds to
the region. An upper level ridge over the islands is helping to
maintain a very stable and mostly dry airmass over the area.
Some moisture areas remain within the shallow boundary layer, and
while the afternoon ended up very dry, its possible for a few
spotty windward and mauka showers mainly overnight and during the
morning hours.

Expect more of the same tomorrow with only a little easing of the
trades to moderate levels Tuesday night and Wednesday as a
weakness develops within the ridge northeast of the islands.
Stable conditions will persist with limited moisture in the trade
wind flow. As a result, expect modest windward rainfall, and aside
from a few afternoon showers on Kona slopes of the Big Island,
leeward areas should be dry.

In the long range, trades may strengthen during the weekend, and
the GFS and ECMWF suggest that an increase in showers will be
possible.


&&

.AVIATION...

Breezy to locally windy trade winds will continue through Tuesday
then gradually ease through the end of the week. Showers and low
clouds will continue to favor windward and mauka areas and bring
brief periods of MVFR. Otherwise, VFR will prevail.

The upstream air mass is still looking relatively dry, but cannot
rule out the need to issue AIRMET Sierra for mountain obscuration
later tonight.

AIRMET Tango for moderate low-level turbulence lee of island
terrain is in effect and will continue into Tuesday due to strong
trades.


&&

.MARINE...

A broad surface high pressure over the central and eastern Pacific
will remain stationary over the next day or so maintaining fresh
to locally strong trade winds. A Small Craft Advisory (SCA)
remains in effect for the typical windier waters around Maui
County and the Big Island through Tuesday but will likely be
extended through Wednesday morning in the next package. A
disturbance will develop far northeast of the state Tuesday night
into Wednesday, weakening trade winds. SCA conditions may drop
off as early as Wednesday as winds ease to moderate to fresh then
persist through Friday.

The current long period south swell has peak and will maintain
High Surf Advisory (HSA) criteria through tonight with the main
energy lingering around 16 seconds. Offshore and near shore buoys
continue to run a couple of feet above guidance thus there still
remains a good chance of continuing the HSA through the day
Tuesday as surf height slowly trend down around or slightly above
HSA criteria. This swell will continue to slowly decline through
Thursday before dropping to background levels Friday.

Rough, choppy surf along east facing shores will remain slightly
elevated through Tuesday before slowly declining as trades
upstream of, and eventually over, the islands weaken. In addition
a small pulse of northeast swell energy is expected to fill in
Tuesday that could provide a small boost along north and east
facing exposures. East shore surf will fall below average by
Wednesday and will decline further through Friday and the
northeast swell quickly fades and trades over and upstream ease.

North facing shores may see a tiny bump from the combination of a
small, medium period northwest swell and the northeast swell
mentioned above Tuesday into Wednesday but will quickly fade
Wednesday night.


&&

.FIRE WEATHER...
The ongoing breezy and dry weather will produce elevated fire
weather concerns through Tuesday, though critical conditions are
not forecast. Improvement is expected as winds decline Wednesday
into Friday.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory until 6 AM HST Tuesday for Niihau-Kauai
Leeward-Waianae Coast-Kahoolawe-Maui Leeward West-Kona-Kauai
South-East Honolulu-Honolulu Metro-Ewa Plain-Molokai Leeward
South-Lanai Leeward-Lanai South-Maui Central Valley South-South
Maui/Upcountry-South Haleakala-Big Island South-Big Island
Southeast.

Small Craft Advisory until 6 PM HST Tuesday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.


&&

$$


DISCUSSION...M Ballard
AVIATION...Farris
MARINE...Almanza