983
FXHW60 PHFO 111351
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
351 AM HST Tue Mar 11 2025

.SYNOPSIS...
Drier trends are forecast for much of this week, as a strong high
pressure system north of the islands keeps breezy to windy trade
winds blowing through Thursday. Trade wind speeds show decreasing
trends to more moderate levels from Friday through the weekend
with expanding daytime sea breezes over terrain sheltered western
slopes of each island. An upper level low moving into the Hawaii
Region from the northwest direction may enhance shower activity
across the state from Saturday into early next week.

&&

.DISCUSSION...
The satellite imagery this morning shows a few bands of clouds
riding into each island on the trade winds. Higher pressure
building in quickly from the north this morning will lower stable
temperature inversion heights aloft and decrease cloud cover
and rain shower activity across the state. A few thunderstorms are
developing along the Big Island leeward wind convergence plume
roughly 100 miles west of Kona. These thunderstorms in the
offshore waters should diminish later today.

A strong high pressure system building north of the Hawaiian
Islands will produce strong and gusty winds across the region for
through Wednesday. These strong winds will peak at wind advisory
levels today through early Wednesday morning over terrain favored
windy areas of Maui County and the Big Island. Lower temperature
inversion heights aloft will tend to compress the lower level
boundary layer and increase these wind speeds over and downwind of
island mountains; mountain passes will also see a sharp increase
in these wind speeds. Stronger winds will continue on Wednesday,
probably just below Wind Advisory thresholds for all islands. Wind
speeds will trend noticeably lower on Thursday with a more
significant decrease in trade wind speeds from Friday into the
weekend as a low pressure system approaches the state from the
northwest direction.

Long range forecast guidance continues to show decreasing wind
trends by this weekend to more moderate levels. These lighter
large scale east-southeasterly winds will allow local scale sea
breezes to expand in coverage over terrain sheltered western
mountain slopes of each island. A cold front approaching the
islands from the northwest direction will stall out a few hundred
miles west of Kauai and form an upper level cut off low by
Saturday. This unstable upper level cold core low may get close
enough to the islands for unstable convergence bands to set up in
the east-southeasterly wind flow. Island convergence plumes
forming to the lee of island mountains may also enhance shower
activity even further. If these unstable cloud bands develop they
may bring periods of moderate to locally heavy rain showers to
portions of affected islands. In any case the eastern to
southeastern slopes of the Big Island should also see an increase
in shower activity by this weekend. These unsettled weather conditions
may last into early next week.

Enhanced rainfall amounts from Saturday into early next week will
be highly dependent upon how close the unstable upper low sets up
relative to each island. Western islands will therefore see
higher chances for enhanced shower activity during this time
period. Stay tuned.

&&

.AVIATION...
Most areas will see prevailing VFR conditions with brief
MVFR conditions possible near the Big Island today. Trade wind
speeds will ramp up and hold in the breezy to strong range for
the next 24 to 36 hours.

AIRMET Sierra for mountain obscuration is currently in effect for
north and east facing slopes of the Big Island. These cloudy
conditions will improve later this morning.

AIRMET Tango remains in effect for moderate low level turbulence
over and downwind of island terrain. This AIRMET is expected to
continue over the next several days due to strong winds.

&&

.MARINE...
A strong high pressure cell building far north of the state will
maintain strong to gale force winds through early Wednesday
morning, then weaken slightly thereafter. Gale Warnings are in
effect through early Wednesday morning for Alenuihaha and Pailolo
Channels and Maalaea Bay. A Small Craft Advisory for all of the
remaining Hawaiian waters will likely be extended into Thursday.
Trade winds should continue to weaken slightly and veer towards
the east- southeast late this week into this weekend as a trough
develops west of the state.

The current small north-northwest swell (340 degree) is expected
to steadily decline today and fade out. A moderate long- period
north- northwest (330 degree) swell will arrive this evening and
peak on Wednesday, producing elevated surf along select north and
west facing shores near advisory thresholds. A similar sized
long- period west- northwest to northwest swell (300 to 320
degree) is expected to fill in Thursday night and peak on Friday.
This swell could once again briefly approach advisory thresholds
for select north and west facing shores on Friday and gradually
decline over the weekend.

Rough surf will continue along east facing shores over the next
several days in response to the persistent strong trade winds
over and upstream of the islands. Surf will near High Surf
Advisory criteria today into Wednesday morning as trades peak in
strength. Surf along south- facing shores will remain small.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 6 AM this morning to 6 AM HST Wednesday for
Lanai Mauka-Kahoolawe-Maui Windward West-Maui Leeward West-
Kohala-Lanai Windward-Lanai Leeward-Maui Central Valley North-
Maui Central Valley South-South Haleakala-Big Island South-Big
Island Southeast-Big Island North.

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

Small Craft Advisory until 6 AM HST early this morning for
Maalaea Bay-Pailolo Channel-Alenuihaha Channel.

Gale Warning from 6 AM this morning to 6 AM HST Wednesday for
Maalaea Bay-Pailolo Channel-Alenuihaha Channel.

&&

$$

DISCUSSION...Bohlin
AVIATION...Bohlin
MARINE...JT