421 
FXHW60 PHFO 240139
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
339 PM HST Wed Jun 23 2021

.SYNOPSIS...

Trade wind weather will transition to a stagnant and mostly dry pattern
featuring afternoon sea breezes and nighttime land breezes 
Thursday through Saturday. Moderate trades and a return to typical
trade wind weather with clouds and showers focused over windward 
areas is expected by Sunday. Trades then become breezy by Monday.

&&

.DISCUSSION...

A weakening front positioned northwest of Kauai is anchoring a col
region characterized by light to variable winds that will ease
into northern portions of the state overnight. Trades will
gradually weaken and veer to a more ESE direction by early
Thursday morning, but not quickly enough to change the overall 
flavor of tonight's forecast. Given the persistence of moist 
northeast flow around trade inversion height, another uptick in 
trade wind showers similar to last night cannot be ruled out. Any 
moderate to heavy showers will once again be highly localized. 

As weakening winds become more southeasterly during Thursday, 
blocked flow courtesy of Big Island will cause a further reduction
to the gradient wind over the smaller islands. Light 
southeasterly/locally variable flow will give rise to a sea 
breeze/land breeze pattern Thursday through Saturday. This will in
turn favor cloud build-ups and isolated to scattered afternoon 
showers over leeward and sheltered areas followed by clear nights 
characterized by light offshore flow. Although ambient moisture
and mid-level stability will inhibit both widespread and deep 
convection, isolated locally heavy downpours will be possible each
day. Model consensus for the return of moderate trades on Sunday,
becoming breezy by Monday, remains in tact. As such, a return to 
typical trade wind weather with showers focused chiefly over 
windward areas can be expected at the outset of next week.

&&

.AVIATION...

Surface high pressure is centered far northeast of the state, 
with a weak ridge extending southwestward to just north of Kauai. 
Light to locally moderate easterly trade winds are forecast to 
remain in place, which will allow clouds and showers to continue 
favoring east facing slopes and coasts throughout the forecast 
period. Lighter background wind flow will result in developing sea
breezes in sheltered leeward areas in the afternoons, with increased
daytime inland cloud cover. Land breezes will take over in these 
areas overnight, clearing the clouds offshore.

There are currently no AIRMETs in effect nor expected through the
forecast period.

&&

.MARINE...

Light to moderate trades will prevail through Saturday, then 
strengthen to moderate to locally strong levels Sunday through 
early next week. Small Craft Advisories may be needed for the 
windier waters around Maui and the Big Island at that time.

Surf along south facing shores will see a series of overlapping
south-southwest and south-southeast swells over the next week. 
These swells should produce surf heights near the summertime 
average (5 ft) through most of next week. The current tiny 
northwest swell should be on the decrease Thursday, but a new 
northwest swell will fill in Friday into Saturday. Surf along east
facing shores will remain small and below the summertime average 
due to the lack of strong trades over or upstream of the state. 

&&

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

&&

$$


DISCUSSION...JVC
AVIATION...TS
MARINE...Kino