112
FXHW60 PHFO 161322
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
322 AM HST Tue Jul 16 2024

.SYNOPSIS...
Broad high pressure north of the state will weaken, resulting in
the breezy trade winds to ease to moderate strength Wednesday
through Friday. Stable and somewhat dry conditions will prevail
through at least Friday, with light showers favoring windward
slopes.


&&

.DISCUSSION...
No changes to the forecast this morning. A broad high pressure
system remains between 30 and 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. The night started off with very few light showers riding
in on the trades, but a few more spotty showers have been seen on
radar over the last couple of hours. Anticipate a few more over
the next several hours, mainly over windward and mauka areas, with
showers diminishing again this afternoon.

The ridge to the north is expected to weaken, which will allow
trades to ease some tonight and Wednesday. 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 trade winds will persist today, then gradually ease
through the end of the week. Light showers and low clouds will
favor windward and mauka areas and bring the potential for brief
periods of MVFR. Otherwise, VFR will prevail.

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


&&

.MARINE...
A broad surface high pressure over the central and eastern Pacific
will remain stationary through today maintaining fresh to locally
strong trade winds. A Small Craft Advisory (SCA) for the typical
windier waters around Maui County and the Big Island through has
been extended through Wednesday morning. A disturbance will
develop far northeast of the state late tonight into Wednesday,
weakening the ridge. SCA conditions may drop off as early as
Wednesday as winds ease to moderate to fresh then persist through
Friday. A high will strengthen north of the state over the weekend
as the disturbance weakens and dissipates. Trades may strengthen
back to moderate to locally strong over and upstream of the state
this weekend into early next week.

The current long period south swell continues to hold in the 16
second range based on near shore and offshore buoy data. Thus
have extended the High Surf Advisory (HSA) through today 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 through the weekend.

Rough, choppy surf along east facing shores will remain slightly
elevated through today before slowly declining as trades upstream
of, and eventually over, the islands weaken. In addition a small
pulse of northeast swell energy appears to have arrived at near
shore buoys and will continue to fill in today. This small swell could
provide a tiny boost along north and east facing exposures. East
shore surf will fall below average by Wednesday and will decline
further Thursday through Friday as 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 today into Wednesday but will quickly fade
Wednesday night.


&&

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


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory until 6 PM HST this evening 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 AM HST Wednesday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.


&&

$$


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