129
FXHW60 PHFO 171313
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
313 AM HST Mon Jun 17 2024

.SYNOPSIS...
A high pressure ridge will remain locked in place north of the
Hawaii region through the rest of this week. A weak upper low
drifting over the state into Tuesday will help produce periods
of showers mainly over the windward and mountain areas in the
overnight to early morning hours. The ridge to the north will
strengthen from Wednesday onward, producing breezy to locally
windy trade winds into next weekend.

&&

.DISCUSSION...
Radar imagery this morning shows scattered to numerous showers
developing over and upstream of windward mountain ranges.
Satellite imagery shows a band of low level clouds upstream of
each island, moving into the windward slopes. This cloud band and
a weak upper level low shown on the water vapor satellite channel
will likely spread periods of showers along the windward and
mountain slopes through the early morning hours. The weak upper
level low continues to lift trade wind inversion heights this
morning to around 7,000 feet at both Lihue and Hilo upper air
observation sites. Temperature inversion heights at this level
will support continued periods of trade wind showers favoring the
windward and mountain areas through early Tuesday morning. This
shower activity will decrease slightly during the mid morning to
afternoon hours.

A subtropical high pressure ridge north of the Hawaiian Islands
will produce moderate to breezy trade winds lasting through
Tuesday. A slight increase in the easterly trade winds into the
breezy to locally windy range will start on Wednesday and
continue into next weekend as the ridge north of the islands
strengthens. A cloud band from the likely remnants of an old East
Pacific front may roll through the islands by Saturday, enhancing
shower activity a bit for next weekend.

Otherwise little changes are forecast in the day to day island
weather pattern with just more typical trade wind weather
continues through the end of this week.

&&

.AVIATION...
Breezy easterly trades will continue, with clouds and showers
favoring windward and mauka locations. Periods of MVFR conditions
will continue over these windward sections through the morning
hours. Otherwise, VFR conditions will prevail.

AIRMET Sierra for tempo mountain obscuration is in effect for most
windward areas. Conditions should improve by mid morning.

&&

.MARINE...
Surface high pressure will remain north-northeast of the area,
then gradually strengthen during the second half of the week. As
a result, the trades will become fresh to locally strong, with
near-gale winds in the Alenuihaha Channel and waters south of the
Big Island beginning Wednesday. The Small Craft Advisory (SCA),
currently in effect for the normally windier areas around Maui
County and the Big Island, will likely continue through the week,
with an expansion to include the waters around Kauai and Oahu on
Wednesday.

Surf along south facing shores will continue to slowly decline as
the south swell fades today. For the rest of the week, expect
only background small, medium to long period, south to southeast
swell energy moving through the local waters.

North shore surf is expected to be small through the week, coming
from small, mainly medium-period, northwest swells. Surf along
east shores will become increasingly rough and choppy from Wednesday
onward as the trade winds strengthen across the state.

&&

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

&&

$$

DISCUSSION...Bohlin
AVIATION...Gibbs
MARINE...TS