Hilo, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

960
FXHW60 PHFO 151302
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
302 AM HST Thu May 15 2025

.SYNOPSIS...
Moderate to breezy trades will continue through Friday, with an
easing and a shift around to the east-southeast expected over the
weekend. A disturbance aloft will bring some heavier showers and
potentially a thunderstorm or two to the Big Island, particularly
during the afternoon hours Friday through Sunday. The trades will
shift back to a more typical east-northeast direction and
strengthen to moderate and breezy levels late Monday through
Wednesday. The disturbance aloft will weaken and shift east of the
state early next week, allowing a return of a more typical, but
wetter than normal, trade wind pattern.

&&

.DISCUSSION...
Currently at the surface, a 1031 mb is centered around 1400 miles
northeast of Honolulu, and is driving moderate trade winds across
the island chain early this morning. Infrared satellite imagery
shows low clouds moving along with the trades, with some jet
stream cirrus streaming over the eastern end of the state. Partly
to mostly cloudy conditions prevail, with cloud coverage the
highest over windward and mauka areas. Radar imagery shows
scattered showers moving into windward slopes and coasts, with a
few showers spilling into leeward communities from time to time.
Main short term focus revolves around the potential for some
heavier showers and a few thunderstorms during the next few days.

High pressure will remain nearly stationary northeast of the state
through Friday, keeping moderate to breezy trade winds in place.
A developing trough to the distant northwest is expected to shift
the low level trade flow around to the east-southeast this
weekend. This will ease the trades into the light to moderate
range over the western islands, while moderate to locally breezy
trades persist over the eastern end of the state. An area of low
pressure is forecast to develop along the trough and shift
northwestward during the first half of next week, while a new high
builds in to the distant north. As a result, we should see the
trades shift around to a more typical east-northeasterly
direction with speeds increasing back to moderate and breezy
levels late Monday through Wednesday.

As for the remaining weather details, a disturbance aloft should
bring enough instability today through the weekend to keep a
wetter than normal trade wind pattern in place. A few downpours
can`t be ruled out where localized sea breezes develop,
particularly during the afternoon/early evening hours Friday
through Sunday. Enough mid-level moisture may work into the region
to allow for the development of a thunderstorm or two over the
interior and leeward sections of the Big Island as well. The
disturbance aloft will shift east of the state and weaken early
next week, allowing a return of a more typical, but wetter than
normal, trade wind pattern.


&&

.AVIATION...
Moderate to breezy trade winds continue to prevail across the
island chain through Friday afternoon, steered by high pressure
centered far northeast of the main Hawaiian Islands. Showers and
occasional low clouds embedded within the trades will favor north
through southeast sections of the islands throughout this period,
especially during the overnight to early morning hours. While VFR
flight conditions will prevail at most locations, periods of MVFR
conditions will be possible within any showers that occur.

AIRMET SIERRA is now in effect for mountain obscurations for
windward sections of Kauai, Oahu, Molokai, and Maui. Conditions
should improve in most areas later this morning, but could return
again tonight. AIRMET Tango remains in effect for moderate low-
level turbulence over and downwind of island terrain. This AIRMET
will likely be needed through at least Friday.

&&

.MARINE...
A strong high will remain nearly stationary far northeast of the
state through the week and continue to bring fresh to locally
strong trade winds to all local waters. A Small Craft Advisory
(SCA) for the windier waters around Maui County and the Big Island
remains in effect through Friday. Windward Big Island waters has
also been added to the SCA due to the locally strong east to east
southeast flow. Winds may ease slightly and veer toward the east-
southeast over the weekend due to a trough far northwest of the
state.

Surf along south facing shores will remain small due to mainly
background energy today. A tiny long-period south-southwest swell
will build in late Friday into the weekend. Otherwise, expect
mainly background energy through the middle of next week.

Surf along east-facing shores will remain rough and choppy the
next several days due to the fresh to locally strong trades. Surf
along north-facing shores will remain small with some background
northwest energy moving through throughout the week and into the
weekend.

&&

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

&&

$$

DISCUSSION...Jelsema
AVIATION...Almanza
MARINE...Shigesato