FXHW60 PHFO 280624
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
824 PM HST Fri Sep 27 2024

.SYNOPSIS...
Moderate trade winds will prevail through the weekend and much of
next week. Trade wind showers will favor windward and mountain
areas in the overnight to early morning hours, especially through
tomorrow morning as a weak disturbance passes over the state. A
slightly drier trade wind pattern is expected from Saturday
afternoon through Monday, followed by wetter trends from Monday
night into Wednesday.

&&

.DISCUSSION...
Local radar imagery this evening shows scattered to numerous showers
moving through the windward and mountain slopes of each island on
the easterly trade winds. This shower activity is enhanced by a
weak disturbance aloft and these wet trends will continue into the
early morning hours.

In the big picture, the high pressure ridge north of the Hawaiian
Islands will begin to weaken slightly starting on Sunday as a cold
frontal system passing through the Central Pacific basin. Moderate
trade winds will continue to blow across the state through much
of next week.

In the rainfall forecast, we continue to see subtle changes in
the day to day shower activity over each island. A weak
disturbance shown clearly on the 700 mb streamlines will continue
to track westward over the islands tonight, keeping a slight
increase in shower activity that favors the windward and mountain
areas through the early morning hours. Brief drying trends will
develop from Saturday afternoon through Monday. Additional bands
of clouds, likely the remnants of an old East Pacific frontal
boundary, will then drift into the state on the trade winds from
Monday night into Wednesday; with increasing shower trends
favoring the overnight through early morning hours.

&&

.AVIATION...
Moderate trades through the weekend. Windward and mauka SHRA can
be expected with some spillover to leeward locations. Brief MVFR
conds are possible in any SHRA, but VFR should generally prevail.

AIRMET Sierra is in effect for mtn obsc for windward portions of
all islands. Conds expected to improve with sunrise.

&&

.MARINE...
Gentle to fresh trade winds will prevail through at least early
next week as weak surface high pressure holds north of the island
chain. Winds will be near the Small Craft Advisory (SCA) level at
times around the Big Island and Maui through tomorrow, but an SCA
is not anticipated. Winds may decline slightly Sunday and Monday
as the surface ridge to the north is weakened, with a slight
increase possible Tuesday or Wednesday.

The current small north-northwest swell will decline through
tonight. A small, medium period north-northwest swell will build
on Saturday and produce north shore surf near September average
Saturday night and early Sunday. A small, medium period northwest
will arrive on Tuesday, shift out of the north Wednesday and
Thursday, and hold into Friday.

The current mix of small, long period south-southwest swell and
short period southwest swell will decline tonight and Saturday.
Another pulse of inconsistent southwest swell originating from
the Tasman Sea will push south shore surf to near seasonal
average late Sunday and Monday. A more consistent south-southwest
swell is expected Tuesday and Wednesday.

East shore surf will remain well below normal through the week.

&&

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

&&

$$

DISCUSSION...Bohlin
AVIATION...Walsh
MARINE...Bohlin