Wildfire in Hawaii, August 10 to 17, 2022

Area Forecast Discussion
National Weather Service Honolulu HI
307 AM HST Wed Aug 10 2022

.SYNOPSIS...
Breezy to locally windy trades will continue through Thursday as
a weak low or surface trough slides by to the south of the state.
The trades will ease back to moderate and locally breezy levels
Friday through the weekend, and perhaps ease even further early
next week. Fairly dry trade wind weather will prevail during the
next 7 days, with showers favoring windward and mauka areas mainly
at night and during the early morning hours. A stray shower may
reach leeward areas at times, but most areas should remain dry.

&&

.DISCUSSION...
Currently at the surface, a 1030 mb high is centered around 1700
miles north-northeast of Honolulu, while a broad trough of low
pressure is located around 450 miles south of the Big Island. The
resulting gradient is producing breezy trade winds across the
island chain early this morning. Radar imagery shows scattered
showers moving into windward areas, with a stray shower or
perhaps a few sprinkles making the trip over the mountains and
into leeward communities at times. Main short term focus revolves
around trade winds trends and rain chances.

High pressure to the distant north-northeast will shift southward
and closer to the islands during the next couple days, while a
weak area of low pressure, or surface trough, slides by around
300-400 miles south of the state. This will keep breezy to
locally windy conditions in place through Thursday, with a peak
in trade wind speeds expected today. With a sharp low level
inversion in place around 5-6 kft today, we will likely see
advisory level winds across portions of Maui County and the Big
Island due to effective funneling and channeling of winds by the
island terrain. As a result, a Wind Advisory is now in effect
through 10 pm this evening. The trades should lower into the
moderate and locally breezy range on Friday, then hold at these
levels through the weekend. A weakness developing in the ridge
north of the islands could ease the trades further early next
week.

As for the remaining weather details, a fairly dry trade wind
pattern should prevail through the forecast period. Showers
will focus primarily over windward and mauka areas during the
overnight and early morning hours. A stray shower may occasionally
drift into leeward areas, although most areas will remain dry.
There remains the potential for a slight increase in showers over
the Big Island Wednesday night and Thursday as the weak low or
surface trough slides by to the south, but guidance remains in
good agreement keeping the deepest moisture associated with this
feature south of the state.

&&

.AVIATION...
Breezy to locally windy trade winds will continue over the
islands through the TAF period, as an area of high pressure
remains anchored well north-northeast of the state. Limited
moisture will generate mainly VFR conditions through early
Thursday, with showers affecting mainly windward and mauka
sections. Some MVFR cigs will occasionally drift across windward
areas this morning, continuing the potential need for AIRMET
Sierra due to tempo mountain obscurations for some windward areas,
especially the Big Island and Maui.

AIRMET Tango remains in effect for low-level mechanical
turbulence leeward of mountains due to windy trades. These
turbulent conditions will continue across the islands through
tonight.

&&

.MARINE...
The islands are sandwiched between a strong surface high pressure
system located far north-northeast of the area, and an elongated
surface trough located well to the south. This is producing
strong trade winds, especially over the eastern half of the
island chain. A Small Craft Advisory (SCA) remains in effect for
all of the waters surrounding the islands of Maui County and the
Big Island, as well the waters south of Oahu through early
Thursday morning. The current forecast keeps SCA conditions in
the typically windier waters adjacent to the islands of Maui
County and the Big Island from Thursday through Friday. The SCA
may need to be extended into this weekend for these same windier
waters.

The strong trades will cause the short-period wind waves to
increase during the next couple of days. Therefore, expect choppy
surf to peak near, or slightly above the seasonal average along
east facing shores through Thursday. Surf heights may trend down
along east facing shores as the trade winds ease to moderate
speeds this weekend. A very small, long-period south swell, and a
small, short-period southeast swell will continue to produce
modest surf along south facing shores through Thursday. Another
small, medium-period south swell may arrive Saturday, which would
maintain small surf along south facing shores this weekend.
Elsewhere, expect nearly flat conditions to persist along most
north facing shores through this weekend.

Monthly high tides are expected to peak during the next couple of
days, with the maximum astronomical high tides occurring during
the afternoon hours. Tide station observations are showing close
to the predicted water levels for most stations around Hawaii. We
do not plan to issue a Coastal Flood Statement at this time, since
the guidance indicates the water level values will likely remain
just below the significant impact levels.

&&

.FIRE WEATHER...
Strong trade winds and low relative humidity values will result in
elevated fire danger today. As a result, a Red Flag Warning is in
effect from 10 AM to 6 PM. Outdoor burning should be avoided.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 10 AM this morning to 6 PM HST this
evening for Niihau-Kauai Leeward-Oahu South Shore-Waianae Coast-
Oahu North Shore-Central Oahu-Waianae Mountains-Molokai Leeward-
Lanai Makai-Lanai Mauka-Kahoolawe-Maui Leeward West-Maui Central
Valley-Leeward Haleakala-Kona-South Big Island-Kohala.

Wind Advisory until 10 PM HST this evening for Lanai Mauka-
Kahoolawe-Maui Windward West-Maui Leeward West-Kohala-Lanai
Windward-Lanai Leeward-Maui Central Valley North-Maui Central
Valley South-Windward Haleakala-South Haleakala-Big Island South-
Big Island Southeast-Big Island North.

Small Craft Advisory until 6 PM HST Friday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.

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

&&

DISCUSSION...Jelsema
AVIATION...SWR
MARINE...Houston