Makawao, Hawaii Weather Forecast Discussion

783
FXHW60 PHFO 170156
AFDHFO
Area Forecast Discussion
National Weather Service Honolulu HI
356 PM HST Tue Sep 16 2025
.SYNOPSIS...
A stable and relatively dry pattern will persist through
Thursday, along with moderate to locally breezy trade winds,
bringing limited clouds and showers to windward and mauka areas.
Increased shower activity is expected Thursday night into the
weekend. A return to a more stable trade wind pattern is expected
early next week.
&&
.DISCUSSION...
Regional visible satellite imagery this afternoon shows a modest
field of low clouds embedded within the moderate to locally breezy
trades focusing mainly windward and mauka. In addition, onshore
flow has brought a build up of clouds and a few showers across the
Kona slopes of the Big Island. Rain gauges have collected only a
few hundredths of an inch across favored windward slopes today. No
significant change in sensible weather is expected through
Thursday given a lack of substantial upstream moisture and
continued stable conditions as dry advection near 700 mb maintains
a firm inversion.
Attention then turns to the potential for a more active shower
pattern late Thursday night into the weekend. A decaying surface
trough far east of the islands and the tail end of a weakening
front draped roughly along 30 to 35N will be pinched off beneath
strengthening high pressure. Moisture from these features will be
drawn into the trade wind flow and bring a boost in showers across
the state beginning late Thursday night, with precipitable water
values climbing towards 2 inches by Friday night into Saturday.
At the same time, a mid- to upper-level low is forecast to set up
near Kauai, leading to modest cooling aloft with 500 mb
temperatures around -8 to -9 C. Forecast soundings show the trade
inversion lifting to near 10 kft or higher as deeper moisture
arrives. While lapse rates will steepen enough to support some
conditional instability, a distinct surface trigger appears to be
lacking. Even so, the combination of deeper moisture and cooler
mid-level temperatures will allow for locally heavier showers and
the potential for a few embedded thunderstorms, especially across
the western half of the state Friday into Saturday. Any heavier
cells should remain fast moving within the persistent trades,
limiting the duration of heavy rainfall at any one location.
Decided to keep thunderstorms out of the forecast with this
afternoon`s package, mostly due to the modest instability paired
with a lack of a distinct lifting mechanism.
Showers will gradually diminish late Sunday into early next week
as upper ridging reestablishes and drier air filters back across
the islands.
&&
.AVIATION...
Locally breezy trades continue through the period. Limited clouds
and showers favor windward and mauka areas with a slight uptick
in shower coverage anticipated tonight. VFR prevails with pockets
of MVFR within passing showers.
No AIRMETs in effect.
&&
.MARINE...
The pressure gradient resulting from the high pressure to our
north and a trough passing south of the state will maintain
moderate to locally strong trade winds through around Thursday and
possibly Friday into the weekend. Winds are expected to ease
slightly Friday into the weekend, but winds may still hold at
Small Craft Advisory (SCA) thresholds for the typical windy areas
around Maui County and the Big Island. Currently the SCA is in
effect through Wednesday afternoon and will likely be extended.
Surf along north facing shores should see an increase by Thursday
as a short-period north swell arrives. This small bump is
expected to peak on Friday out of the north to north- northeast
direction. A fetch of strong trade winds developing far northeast
of the state Wednesday into Thursday should produce a moderate
increase along east and select north facing shores Friday into
the weekend. Otherwise, a small bump from the northwest is
expected this weekend.
Mainly background south and southeast energy is expected along
south facing shores over the next few days. A slight increase of
southeast energy is possible Wednesday or Thursday. Otherwise, a
small to moderate long-period swell will boost south shore surf
this weekend with surf heights back up to around the September
average (6 feet) this weekend.
&&
.FIRE WEATHER...
Expect decreasing fire weather risk as humidity gradually
increases through the week and into the weekend. Rain chances will
increase Thursday night into the weekend as deep pockets of
moisture filter in on the trades, helping to potentially further
alleviate fire weather concerns. Sustained winds briefly hover
near to below the critical fire weather threshold each afternoon
through Thursday, then trend slightly lighter for the weekend.
&&
.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST Wednesday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.
&&
$$
DISCUSSION...Farris
AVIATION...JVC
MARINE...Kino
FIRE WEATHER...Farris

NWS HFO Office Area Forecast Discussion