Kahului, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

446
FXHW60 PHFO 020645
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
845 PM HST Sun Feb 1 2026

.SYNOPSIS...
A cold front will march eastward down the island chain from
late Monday afternoon onward, finally stalling out and
diminishing near the Big Island by Tuesday afternoon.
Southwesterly winds will strengthen through Monday with breezy to
locally strong southwest winds expected by Monday afternoon.
Northwesterly winds with cool and dry conditions will follow
behind the frontal passage. A stronger weather disturbance could
impact the state late Friday into next weekend with heavy rain and
thunderstorms.

&&

.SHORT TERM UPDATE...
The satellite imagery this evening shows quickly moving cloud
bands just west of the islands, a good indicator of strengthening
southwest winds developing ahead of the next cold front
approaching the state from the northwest direction. These strong
southwesterly winds may exceed our Wind Advisory thresholds on
Monday over mountain ranges, and along north through east slopes
of island mountains. A few shower bands are developing in the warm
and unstable southwest flow ahead of the front. However, the main
rainfall event will occur as the front passes eastward through
each island from late Monday afternoon through Tuesday. Cool and
drier northwesterly winds will blow in as the front passes through
each island. Drier air will more efficiently cool off the
atmosphere during the overnight hours keeping our overnight and
early morning low temperatures well below normal.

&&

.PREV DISCUSSION...
Issued at 355 PM HST Sun Feb 1 2026

Starting tonight, a cold front approaching the state from the
northwest will cause southwesterly winds to gradually increase
into Monday with breezy to strong (15 to 25 mph) southwesterly
winds expected across the state by Monday afternoon. Wind gusts of
40 mph will be possible especially areas downwind of the mountain
ranges. One area that could see stronger wind gusts and meet the
Wind Advisory criteria will be over windward Oahu. Latest High Res
models have trended stronger with the 850mb winds and is now
showing anywhere from 30-40 knots at 850mb. With an inversion
expected a little above the ridge tops, this should provide a
favorable setup for gusty downslope winds with wind gusts of 50
mph possible Monday afternoon through the evening. Elsewhere
across the state, we could see wind gusts approach the Wind
Advisory threshold, but at this time the best chance seems to be
over typical windward areas of Oahu.

As far as rainfall, prefrontal showers will continue to increase
tonight into Monday, which should bring some passing showers
focused over our typical leeward areas. The main band of moisture
will be along the frontal boundary and will be short-lived with a
brief period of moderate rain possible. The threat for heavy rain
will be minimal due to stable conditions aloft. The front should
be moving through Kauai late Monday afternoon into the evening,
over Oahu on Monday night, and over Maui County Tuesday morning.
The front should then dissipate around the Big Island Tuesday
afternoon and evening. Behind the front, we should see cool and
dry conditions with moderate northwesterly winds. Dewpoints will
get down into the 50s behind the front, so Tuesday and Tuesday
night should feel quite cool.

Over on the summits of Haleakala and the Big Island, upper level
winds will increase Monday night and will likely reach Wind
Advisory thresholds for the summits of Big Island and Haleakala.
No wintry precipitation is expected with the frontal boundary due
to the shallow nature of the front.

After the frontal passage, we should see fair weather conditions
persist for a few days due to a surface ridge of high pressure
over the state. Light winds with clear mornings and partly cloudy
afternoons are expected Wednesday and Thursday.

Long range models are in pretty good agreement with an upper
level trough approaching the state next weekend. At the surface,
we should see a cold front approach the state late Friday into
Saturday. While details still remain uncertain at this point, both
the operational GFS and ECMWF and its AI models show some type of
upper level cut off low developing over the state or southwest of
the state. Depending on where this low develops, we could see a
complex weather pattern next weekend with the threat of heavy rain
and thunderstorms.

&&

.AVIATION...
Issued at 355 PM HST Sun Feb 1 2026

Mostly VFR with isolated MVFR in low clouds and showers through
early evening, then VFR overnight. Southwest low-level flow has
developed (altered locally by terrain, of course). This flow will
strengthen through the night and become even stronger Monday
afternoon. Cloud coverage and shower trends will increase Monday
from west to east as a cold front approaches the islands. The cold
front is forecast to reach PHLI around 6 PM HST, bringing gusty NW
winds and showers.

No AIRMETs in effect and none are expected.

&&

.MARINE...
Issued at 355 PM HST Sun Feb 1 2026

A surface ridge will continue to drift southward over the islands
today, leading to gentle to moderate south to southwest winds.
Southwest winds will become fresh to strong late tonight and
Monday as a front approaches. A Small Craft Advisory (SCA) has
been issued for most waters west of the Big Island and will be in
effect from midnight HST tonight through Monday night. The front
will move down the island chain Monday night and Tuesday, bringing
gusty winds and heavy showers. Northwest winds behind the front
will diminish and shift out of the east on Wednesday, followed by
a return to southerly winds Thursday. Another front will likely
reach the state late Friday or Saturday.

The current west-northwest swell will continue to decline through
Monday, with another round of extra-large surf due Tuesday. Surf
along north and west facing shores will diminish to small heights
by Monday morning, followed by an increase during the afternoon as
forerunners of the next northwest swell arrive. The next northwest
swell (310 to 325 degrees) will build rapidly Monday night and peak
Tuesday and Wednesday as overlapping pulses pass through Hawaiian
waters. Surf along most north and west facing shores will easily
exceed High Surf Warning levels, with combined seas exceeding the
10 foot SCA threshold in many areas. The swell will decline
Thursday and Friday, with surf falling below High Surf Advisory
levels Thursday night. Another large swell is possible late Friday
and Saturday.

Surf along east and south facing shores will remain small through
much of the week, aside from a brief boost along south facing
shores with the increase in southwest winds as the front approaches
on Monday. An increase is possible along east shores next weekend.

A Coastal Flood Statement remains in effect through midday Monday,
as peak monthly tides coincide with higher than predicted ocean
levels. Expect minor flooding of low-lying coastal infrastructure
as well as some some beach erosion during the peak high tide between
midnight and sunrise Monday.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory from midnight tonight to 6 AM HST Tuesday
for Alenuihaha Channel-Kaiwi Channel-Kauai Channel-Kauai Leeward
Waters-Kauai Northwest Waters-Kauai Windward Waters-Maui County
Leeward Waters-Maui County Windward Waters-Oahu Leeward Waters-
Oahu Windward Waters-Pailolo Channel.

&&

$$

UPDATE...Bohlin
DISCUSSION...Kino
AVIATION...Parker
MARINE...TS