658
FXHW60 PHFO 281354
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
354 AM HST Fri Feb 28 2025

.SYNOPSIS...
A stationary front located northwest of the state will produce
southerly winds across the western half of the state while
southeasterlies persist across the eastern half of the island
chain today. A dry and stable regional atmosphere has the best
chances for showers occurring over leeward areas and at higher
elevations. Trade winds will return early next week and introduce
a pattern change of higher frequency showers across more windward-
facing exposures.

&&

.DISCUSSION...
A cold front approaching the islands from the northwest will
stall today as it encounters mid to upper ridging that is centered
over and east of the islands. The surface reflection of a benign
stationary boundary will temporarily weaken the pressure gradient
that is emanating from high pressure positioned approximately
1,400 miles northeast of the area. The position of the surface
ridge going into the weekend will continue to promote a generally
gentle southerly wind pattern over more western islands and
southeasterly breezes across the eastern half of the state. Recent
radar and satellite imagery have depicted very light and isolated
north-moving showers passing across more leeward areas within
this southerly steering flow. With little change in the synoptic
over the Central Pacific, this trend will continue through
tomorrow. A weaker wind regime will also lend itself to more
localized breeze activity as afternoon sea breezes thicken cloud
cover and introduce light showers to communities further within
the interior. The front northwest of Kauai is stalling north of
the area early today and will therefore keep its attendant
moisture and more widespread showers north of the island chain.
The western half of the state will experience more cloud cover and
shower activity over leeward areas within this southern flow
regime. Southeasterly flow will allow for more cloud build up and
frequent showers that will favor southeast-facing coasts and mauka
slopes of Big Island and Maui County.

Surface ridge axis southwest of high pressure centered far
northeast of the area will remain draped over the islands this
weekend as mid to upper level ridging builds in overhead. Warm
and muggy conditions will persist as this gentle southerly flow
maintains elevated mid to upper 60 dew points. While a series of
fronts pass north of the state and provide minor fluctuation in
wind behavior, this general southern wind pattern will remain in
place through Sunday. Rainfall accumulation will be very minimal
through the weekend as mid-level ridging provides subsidence, in
tandem with a relatively dry air mass, to the lid on any significant
shower activity. A new front approaching from the northwest early
next week will likely become parallel to the upper level westerlies
and dissipate just before it reaches the state. Strong ridging at
all levels will expand in north of the state. A large surface
high moving to the east north of the chain will be the impetus of
returning breezy to locally windy (at elevation) trade winds going
into the middle of next week. Ribbons of higher moisture being
advected in on newly established trades, along with a touch more
instability in response to lowering heights/cooler temperatures
aloft from a trough passing far north of Hawaii, may lead to a
more wet trade wind pattern late next week.

GOES GeoColor daytime imagery, surface and air quality observations
show vog continuing to impact the majority of the state from Big
Island to Oahu. SO2 emissions from areas of Kilauea`s Halema`uma`u
crater are being caught up and transported within the south
southeast lower level winds. The most recent eruption did pause
this morning and this will likely lead to a reduction in overall
emissions and subsequent vog coverage the next several days. As
trades build back in early next week, any lingering upstream vog
will be carried westward across the islands. Vog concentrations
will likely thin out as strengthening trades better mix out haze
through a deeper boundary layer.


&&

.AVIATION...
A front to the north and a surface ridge to the south of the
Hawaiian islands will maintain light to moderate southerly winds.
These southerly winds are expected through at least tomorrow. Dry
and stable conds with isol SHRA and low cigs possible. Brief MVFR
conds can be expected in SHRA, otherwise VFR prevails.

Hazy conds should continue through at least tomorrow due to
Kilauea volcanic activity and southerly winds. This could lead
to pockets of reduced vsbys.

No AIRMETs in effect.


&&

.MARINE...
A front just north of Kauai will lift northward today, with a new
front then approaching from the west over the weekend. Light to
moderate southerly winds will prevail over the western islands
through Saturday, while light to moderate east-southeasterly
winds hold over the eastern end of the state. The new front will
stall out and weaken into a trough west of the islands Sunday and
Sunday night, allowing trade winds to gradually fill in and
strengthen. A new high building north of the state early next
week, will bring strong trade winds back to the island chain.

A large northwest swell will continue to build from northwest to
southeast down the island chain through the morning hours, peak
late morning through the afternoon, then gradually lower tonight
through the weekend. A High Surf Warning is now in effect for
north and west facing shores of most of the smaller islands
through 6 AM Saturday. A Small Craft Advisory is also in effect
due to elevated seas for most marine zones though 6 AM Saturday.
A High Surf Advisory has been issued for west facing shores of
the Big Island through 6 AM Saturday. Advisory level surf will
likely linger for most of the areas under the current headlines
though the day Saturday.

A new moderate to large northwest swell is due in early next week,
which could bring another round of advisory level surf to most
north and west facing shores Monday and Tuesday. This swell will
then gradually lower through Thursday with a new large northwest
swell possible late next week.

Surf along south facing shores will remain very small and
dominated by background energy through late next week. Surf along
east facing shores will remain very small through the weekend.
East shore surf will begin to rise with the returning trades
Monday and Tuesday, with surf rising to above normal levels by the
middle of next week.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Warning until 6 AM HST Saturday for Niihau-Kauai
Leeward-Waianae Coast-Oahu North Shore-Maui Windward West-Kauai
North-Molokai Windward-Molokai North-Molokai West-Windward
Haleakala.

High Surf Advisory until 6 AM HST Saturday for Kona-Kohala.

Small Craft Advisory until 6 AM HST Saturday for Kauai Northwest
Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-
Oahu Windward Waters-Oahu Leeward Waters-Kaiwi Channel-Maui
County Windward Waters-Alenuihaha Channel-Big Island Windward
Waters.


&&

$$


DISCUSSION...Blood
AVIATION...Walsh
MARINE...Jelsema