Haiku-Pauwela, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

021
FXHW60 PHFO 190321
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
521 PM HST Thu Dec 18 2025

.UPDATE...
Discussion updated to include extension of flood watch for Kauai
and Niihau through 6 AM HST Friday and cancellation of flood watch
for Oahu.

&&

.SYNOPSIS...
A band of moderate to heavy rain over Oahu today will move toward
Kauai County this evening. A flood watch is likely to be extended
over Kauai County tonight. An area of moisture is forecast to
move into the state from the Southeast Friday into Saturday, and
yet another band of moisture will move in from the east early next
week. Trade winds will become re-established over the state
Saturday, bringing a significant change to the southerly winds
that have dominated our weather most of the past week.

&&

.DISCUSSION...
Radar and satellite have shown a persistent area of showers moving
southwest to northeast across Oahu today. The largest rainfall
amounts have ranged from 1 to over 2 inches in the past 6 hours,
favoring higher elevations on the leeward side. Thunderstorms were
noted over Oahu last night, but no lightning has been detected
over land since sunrise. The other islands have been mostly dry
today, with mostly sunny skies this morning giving way to mostly
cloudy skies this afternoon.

The flood watch currently covering Oahu and Kauai counties will
almost certainly be extended overnight for Kauai County. We expect
the band of precipitation presently over Oahu to shift north and
west this evening, brining another round of moderate to heavy
rainfall to Kauai and Niihau, before moving off away from the
state tomorrow. Just as that area is moving away, a new area of
enhanced moisture is expected to move northwest into the state
Friday afternoon and Saturday. Showers from this system will be
less numerous and less heavy compared to the past few days.

This latest area of moisture will be pushed off to the northwest
by a return of the trades Saturday night into Sunday. Enough
moisture could hang around Kauai County for continued showers
into Monday, but the rest of the state should be noticeably
drier. Late Monday into Tuesday, strengthening trades will bring
in yet another band of moisture, this time from the northeast.
The current forecast has this band moving through the state by
late Wednesday and then off to our west next Thursday.

&&

.AVIATION...
Kauai and Oahu socked in with MVFR cigs this afternoon and little
change is anticipated through the very near term. Convergent SW
flow supports convection training over Oahu for the next several
hours with pockets of IFR within heavier showers. This activity
will refocus over Kauai this evening into tonight resulting in
similar conditions there. Diminishing showers and an emergent land
breeze will bring improving conditions to Oahu after sunset though
pockets of showers may still drift over leeward areas overnight.
VFR conditions with little to no shower activity from Molokai
through Big Island, except for PHNY where low clouds hang over the
terrain.

Visible imagery shows an upstream pocket of moisture about 200
miles south of the Big Island that is wrapping into southerly flow
and will favor a threat for showers over Oahu and possibly
interior sections of Maui County on Friday.

AIRMET Sierra for mountain obscuration remains in effect for
Kauai, Oahu, and Lanai.

&&

.MARINE...
A trough near Kauai and Oahu will continue to bring numerous
showers and isolated to scattered thunderstorms over the western
coastal waters through Friday. While gusty winds can be expected
around any thunderstorms, generally gentle to locally moderate
southerly winds continue east of the trough, with gentle to
moderate southeasterly winds to its west. Winds will slowly
decline through Friday night. A Small Craft Advisory (SCA) remains
in effect for the waters around Kauai and Oahu through tonight,
mainly for the north-northwest swell moving into the western
waters. Easterly trade winds will gradually build from east to
west this weekend with the potential for SCA conditions over the
windier waters and channels around Maui County and the Big Island
by Sunday into early next week.

Surf along north facing shores will remain elevated with a mix
across the spectrum from the west northwest to the north. Based
on the spectrum plots at the buoys, two north-northwest swells
with similar heights and periods have been moving into the region
today and seem to suggest that the models were overpredicting as
they erroneously combined these two separate swells. With that
said, surf along north and west facing shores is peaking now into
the early evening, then will gradually fade into Friday. A High
Surf Advisory (HSA) will remain in effect for north and west
facing shores of Kauai, Oahu, and Molokai and north facing shores
of Maui through tonight. A combination of the north northwest and
north swells will keep surf heights elevated through the weekend
but guidance shows it remaining just below HSA levels, then surf
heights are expected to drop into early next week.

East facing shores will remain small given the lack of trade winds
upstream of the islands, but areas exposed to the north swell
will see an uptick through the rest of the week. As trade winds
fill in later this weekend, east shores could become rough and
choppy by early next week. Surf along south facing shores will
remain small through this evening due to short period wind wave
chop, mainly over the western islands along the boundary, but
elsewhere should remain flat to tiny through the weekend into
early next week.

&&

.FIRE WEATHER...
A flood watch continues this afternoon for western islands, and
will most likely be continued in Kauai overnight. These showers,
along with light winds and generally high relative humidities,
will keep conditions below critical fire thresholds through the
next few days. Longer range forecast show little chance for
dangerous fire weather well into next week.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Flood Watch through late tonight for Niihau-Kauai-

High Surf Advisory until 6 AM HST Friday for Niihau-Kauai
Leeward-Waianae Coast-Oahu North Shore-Maui Windward West-Kauai
North-Molokai Windward-Molokai North-Molokai West-Maui Central
Valley North-Windward Haleakala.

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


&&

$$


UPDATE...Parker
DISCUSSION...Parker
AVIATION...JVC
MARINE...Farris
FIRE WEATHER...Parker