Kaumakani, Hawaii Weather Forecast Discussion

346
FXHW60 PHFO 050145
AFDHFO
Area Forecast Discussion
National Weather Service Honolulu HI
345 PM HST Thu Sep 4 2025
.SYNOPSIS...
Light to moderate trade winds can be expected through the weekend
as weak ridging remains north of the islands. A normally dry
summertime shower pattern can be expected for the next few days
until Sunday when an area of enhanced trade wind moisture moves
through. After that, uncertainty remains elevated regarding
potential impacts from Hurricane Kiko, but thus far, increased
showers are expected statewide.
&&
.DISCUSSION...
A dry and stable summertime trade wind pattern is currently in
place supported by mid level ridging and a 1021 mb high to the
northeast. Satellite and radar data from this morning showed
partly cloudy skies with a few showers moving through the area on
the trade winds. This pattern will continue through the weekend
with periods of showers impacting mainly windward and mountain
areas, as well as favoring the night time and early morning hours.
Winds will remain moderate and then local sea/land breezes can be
expected by Saturday as trade winds weaken slightly. The strong
mid level ridging which is currently inhibiting shower intensity
is forecast to gradually weaken beginning Saturday evening as an
upper level low to the far north of the islands becomes cut off
from the jet stream and moves south towards the islands. As
stability gradually decreases due to the upper low, a mid level
trough with enhanced moisture looks to move through the islands
Sunday afternoon through Sunday evening, enhancing trade wind
showers.
Following the passage of the mid level trough and its associated
moisture on Sunday night, uncertainty in the important forecast
details remains high due to the evolution of Hurricane Kiko.
Currently, it looks like a band of dry air will fill in on Monday
before moisture associated with Hurricane Kiko fills in from the
east on Monday night. The NHC is currently forecasting Kiko to
pass just north of the Big Island as a Tropical Storm on Tuesday.
Kiko`s wind field is forecast to stay mostly confined to the
northern half of the center. Statewide, flash flooding is a
possibility, conditional on Kiko`s track, intensity, and its
interaction with the upper level low that is expected to remain
in the area through much of next week. At a minimum, increased
showers are expected through much of next week. Additional details
are forthcoming as forecast confidence increases; for official
forecasts regarding Hurricane Kiko, refer to the National
Hurricane Center.
&&
.AVIATION...
Moderate trade winds will prevail over the island chain
throughout the next several days, and will continue to become
lighter by Friday night into the weekend. Although brief periods
of low clouds and showers will be possible over windward slopes
during the overnight hours, VFR conditions will prevail throughout
the forecast period at most locations. Only brief MVFR ceilings
and visibilities will be possible within any showers that do form.
There are currently no AIRMETs in effect, and none are anticipated
through tonight.
&&
.MARINE...
A weak surface ridge just north of the state will remain nearly
stationary through Friday and will maintain moderate trade winds.
A weak trough is expected to develop just north of the ridge over
the weekend and will cause the winds to decrease to gentle to
moderate speeds with localized sea breezes.
Hurricane Kiko, approximately 1400 ESE of Hilo, continues to
track westward in the Eastern Pacific, and is forecasted to move
into our offshore waters as a Tropical Storm Monday night.
Tropical Storm conditions are possible over the offshore waters
starting Monday and could linger through the middle of the week as
it tracks west-northward. As far as our coastal waters, the
latest forecast from the National Hurricane Center has Kiko
centered very close to the Big Island Windward waters on Tuesday.
Although it is too early for any specifics, Tropical Storm
conditions will be possible around the Big Island waters as early
as Monday.
Surf along north facing shores will remain tiny to small over the
next few days as reinforcing small short-period north-northwest
swells are expected. In the extended forecast, the northwest
Pacific looks to get active as low pressure systems traverse the
basin over the weekend sending the potential for a few small to
moderate northwest swells during the middle of next week. Surf
along south facing shores will see background energy through the
week before a small to moderate long-period south-southwest swell
fills in and peaks over the weekend. Below average surf is
expected to continue along east facing shores through the rest of
the week. In the extended forecast, easterly energy from Tropical
Cyclone Kiko is possible as early as this weekend. This will
bring the potential for surf to reach High Surf Advisory criteria
as early as Sunday or Monday. Warning level surf will be possible
as Kiko moves closer to the Hawaiian Islands on Tuesday. Surf
heights for Tuesday will be highly dependent on the track and
intensity of Kiko as it nears the state.
Peak monthly high tides, combined with water levels running
higher than predicted, may lead to minor flooding along the
shoreline and in low-lying coastal areas. A Coastal Flood
Statement remains in effect through Sunday afternoon.
&&
.FIRE WEATHER...
Typical dry summertime trade wind conditions will remain in place
through the next few days, keeping fire weather conditions
elevated, but below critical thresholds. By Sunday afternoon, a
passing trough could bring some increased moisture, elevating
relative humidities before drying out again on Monday. By Monday
night, moisture associated with Hurricane Kiko will start to fill
in and depending on the track and intensity, could significantly
lower fire weather conditions.
&&
.HFO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Tsamous/JVC
AVIATION...Vaughan
MARINE...Kino
FIRE WEATHER...Tsamous/JVC

NWS HFO Office Area Forecast Discussion