High Surf in Hawaii, November 4 to 5, 2019

Area Forecast Discussion
National Weather Service Honolulu HI
332 AM HST Mon Nov 4 2019

.SYNOPSIS...
A front will diminish over the western portion of the main island
chain through today, with scattered showers expected to linger
over Kauai. The eastern half of the state will remain relatively
dry in this variable wind pattern. Gentle trade winds will return
on Wednesday and Thursday, then weaken to light and variable on
Friday and Saturday as another cold front approaches the islands
from the northwest.

&&

.DISCUSSION...
Satellite and radar imagery show showery broken to overcast low
clouds clouds over Kauai and Oahu associated with a weakening
frontal boundary. These clouds will slowly drift northwestward
over the next 24 hours with lingering isolated to scattered
showers expected over Kauai. Elsewhere, fairly stable conditions
will limit shower activity.

Models show a low far to the north of the state will continue to
move northward away from the island chain. By Wednesday, the
subtropical ridge will build back in north of the state, with a
brief period of gentle trade winds expected from Wednesday to
Thursday. Shower activity will remain fairly isolated, favoring
windward and mountain areas in the overnight to early morning
hours.

On Friday, models show another low moving into the Central
Pacific basin, with a weak cold front stalling out just north of
the state. Wind speeds will weaken, becoming light and variable
again through the upcoming weekend.

&&

.AVIATION...
A stalled front over the western end of the state will begin to
retreat northward today and diminish. Moisture accompanying this
feature will support modest cloud coverage and spotty showers over
Kauai and Oahu. Periods with MVFR CIGS/VSBY will likely continue
over these areas through the morning hours. Mostly dry conditions
should hold over the eastern end of the state, especially through
the early morning period today as the land breeze holds. The best
chance for clouds and showers over these areas will be later this
afternoon across interior areas as the sea breezes push inland.

AIRMET SIERRA is currently in effect for mountain obscuration
across Kauai and Oahu. This will likely continue for at least
Kauai through the morning hours before conditions improve.

&&

.MARINE...
A weak cold front will dissipate near Kauai through today,
keeping mainly light winds in place across the marine area. High
pressure will build north of the state Tuesday through Friday for
a return of light to moderate trades.

A large northwest swell will build today. Surf will rise quickly
to advisory levels and approach warning levels into tonight as
the swell peaks. Seas are expected to rise above Small Craft
Advisory threshold as well, remaining elevated through tonight
for exposed coastal waters. This swell is expected to slowly
subside through rest of the week with a few small reinforcements
during that period. A moderate northwest swell is possible next
weekend.

A couple out-of-season, south-southwest to south swells are expected
late next week, rising to around the summer average beginning Friday.
East shore surf will remain well below seasonal levels.

&&

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

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

&&

DISCUSSION...Powell/Bohlin
AVIATION...Gibbs
MARINE...Powell