Wildfire in Hawaii, April 23 to 24, 2020

Area Forecast Discussion...CORRECTED
National Weather Service Honolulu HI
519 AM HST Thu Apr 23 2020

.SYNOPSIS...
High pressure north of the state will bring moderate to locally
breezy conditions to the island chain through the weekend. The
trades may ease a bit early next week as a front weakens the ridge
north of the state. Fairly typical trade wind weather will
prevail through the middle of next week, with showers favoring
windward and mauka areas and a stray shower reaching leeward
communities from time to time. High clouds will remain rather
thick at times through Friday night, before shifting east of the
state on Saturday.

&&

.DISCUSSION...
Currently at the surface, the remnants of an old frontal boundary
are nearly stationary around 150 miles northwest of Kauai, with a
1027 mb high centered 1250 miles northwest of the state and a
1031 mb high located around 1750 miles east-northeast of
Honolulu. The dual highs are continue to exert more of an
influence on the gradient across the island chain early this
morning, with moderate trades now in place statewide. Infrared
satellite imagery shows a mix of high and low clouds across the
state, resulting in partly to mostly cloudy conditions. Radar
imagery shows scattered showers moving into windward areas, with
a few showers spilling over into leeward locales. Main short term
concern revolves around trade wind trends and rain chances during
the next few days.

Surface ridging north of the islands will become more dominant
today, allowing the trades to strengthen across the area.
Moderate to locally breezy trades are expected to develop
statewide by this afternoon, with similar speeds expected through
the weekend as surface ridging holds firm north of the island
chain. The trades will ease a bit during the first half of next
week as a front passes north of the state and weakens the surface
ridge.

As for weather details, fairly typical trade wind conditions will
prevail through the middle of next week. It may be a bit drier
than normal however, due to precipitable water values fluctuating
between 0.8 and 1.2 inches. Overall, rainfall amounts are expected
to remain light during the next 7 days, with showers favoring
windward and mauka areas and a stray shower drifting leeward from
time to time. Showers will be most prevalent at night and during
the early morning hours.

Jet stream cirrus will keep a fair amount of high cloud cover in
place through Friday night, which may be rather thick at times.
The high clouds will shift east of the state on Saturday.

&&

.AVIATION...
Expect moderate to locally breezy trade winds today. Most of the
state will be dry with the possibility of some low clouds and
showers on the windward side of the mountains. An upper level
trough will pass over the state but as of now, we are not
expecting much in the way of turbulence.

No AIRMETs are currently in effect or expected through this
forecast period.

&&

.MARINE...
Fresh to locally strong trade winds will persist into the weekend
as surface high pressure remains in place far north of the state.
A Small Craft Advisory (SCA) is in effect for the typically windy
areas around Maui and the Big Island through Friday afternoon and
will likely need to be extended through the weekend, since trade
winds should be at similar strength. Trades may drop slightly
early next week.

An active, winter-like northwest swell pattern will continue
into Friday. The latest in the recent series of northwest swells
is maintaining advisory level surf along exposed north and west
facing shores from Kauai to Maui this morning and is contributing
to elevated seas requiring an SCA for seas around 10 ft near
these islands. Another pulse of northwest swell is slowly building
at the offshore buoys and will spread across local waters today.
Resulting surf along north and west facing shores will exceed
advisory levels and may approach High Surf Warning levels during
the peak of the swell tonight. For now, we are keeping a High Surf
Advisory in place, as well as an SCA for seas, through Friday
afternoon. In addition, local tide gauges continue to register a
sea surface anomaly of about a half of a foot. The coinciding
peak of the surf and high water levels should make for above
average coastal wave overwash around the time of high tide
tonight.

Small surf will prevail for south and east shores for the next
week. The current, inconsistent south swell will fade today, with
only background southerly swells expected through the middle of
next week. East shore surf remains well below April normal. As
trades rebuild over and upwind of the islands during the next
couple of days, east shore surf will rise to near April average,
then drop slightly early next week.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory until 6 PM HST Friday for Niihau-Kauai
Windward-Kauai Leeward-Waianae Coast-Oahu North Shore-Oahu
Koolau-Molokai-Maui Windward West-Maui Central Valley-Windward
Haleakala.

Small Craft Advisory from 6 AM this morning to 6 PM HST Friday
for Oahu Leeward Waters-Maalaea Bay-Pailolo Channel-Alenuihaha
Channel-Big Island Windward Waters-Big Island Leeward Waters-Big
Island Southeast Waters.

Small Craft Advisory until 6 PM HST Friday for Kauai Northwest
Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-
Oahu Windward Waters-Kaiwi Channel-Maui County Windward Waters.

&&

DISCUSSION...Jelsema
AVIATION...Chevalier
MARINE...Wroe