Kapaa, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

342
FXHW60 PHFO 230609
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
809 PM HST Fri Nov 22 2024

.SYNOPSIS...

Gentle trade winds will weaken overnight, becoming light and
variable Saturday and Sunday allowing for overnight land breezes
and afternoon sea breezes to develop. A dry and stable airmass
will remain over the state, limiting rainfall. A weak shallow
front may move across the western end of the island chain Sunday
night into Monday, bringing only modest showers and gentle
northerly winds. Light to moderate trades may return by the middle
of next week.

&&

.DISCUSSION...

Currently, satellite imagery shows high clouds continuing to fill
in across the state from the west as a weak jet streak develops
aloft, along with some low clouds developing across island
interiors with sea breeze activity. Radar activity is rather quite
this evening with only few light isolated showers moving over
windward areas over Maui and the Big Island. An area of clouds and
showers just east of the Big Island will keep this trend through
the evening. As winds ease overnight and early morning, expect a
land breeze to form and pushing low level clouds offshore.

Saturday and most of the day Sunday will remain on the drier side
as the dry and stable airmass lingers over the state. Expect light
and variable winds through the weekend which will allow for land
breezes to develop overnight and early morning. Clouds will begin
to develop inland and upslope as sea breezes during the day. Dew
points will remain in the lower to mid 60s across most locations,
allowing overnight lows to drop to a few degrees below normal
through the weekend and keeping afternoons pleasant with lower
relative humidity values. In addition, the high clouds associated
with the jet streak aloft will begin to thin out across the
western half of the state Saturday afternoon into evening and then
across the eastern end by Monday as the jet streak gradually
shifts south and east of the state.

The GFS and ECMWF have come into better agreement on bringing a
weak cold front to Kauai`s doorstep Sunday evening, and then
having it dissipate as it gradually moves towards Oahu and Maui
County on Monday and Tuesday. Impacts look to be minimal with
gentle northerly winds moving in behind the front, along with the
potential for a slight uptick in shower activity for the western
end of the state. Low level tropical moisture moving in east of
windward Big Island will bring a little bump in shower activity
for south and east facing slopes of the eastern half of the state
Saturday night into Sunday. Despite some model discrepancies
Tuesday and beyond, mid level ridging will build in from the west
and surface high pressure will set up northeast of the state by
Thursday and bring a return to light to moderate easterly trades
heading into the latter part of the week.

&&

.AVIATION...

Light winds with sea/land breezes are expected through tomorrow.
Some light SHRA and isol brief MVFR conds are possible in the
evenings primarily along windward and mauka locations. Otherwise,
VFR conds should prevail.

No AIRMETS are in effect. However a subtropical jet will move
through the state the next several days, which could produce some
light to moderate turb tomorrow between FL270 and FL380, and thus
we may need AIRMET Tango if and when conds warrant.

&&

.MARINE...

Weak high pressure will hold just north of Hawaiian offshore
waters through most of the weekend. A weak front will approach
the far western waters Sunday night then dissipate over Oahu on
Monday. Winds are expected to remain light and variable through
the weekend and into Monday. Light to moderate trade winds will
return later next week when high pressure rebuilds to the north
of the state.

The current, small, medium period, NNE (360-020) swell impacting
the Islands will be at its peak Saturday afternoon. A second
moderate, medium period pulse from the same source will fill in
Saturday and provide reinforcement. Lastly, an overlapping NW
swell (320 degrees) will build on Saturday and peak during the day
Sunday. Surf along north and west facing beaches will remain
small on Saturday, approach High Surf Advisory (HSA) criteria on
Sunday, then subside early next week. A Marine Weather Statement
is in effect for harbor surges, particularly at Hilo and Kahului
harbor, generated by the two more northerly swells.

Surf along east facing shores will become more elevated Saturday
into Sunday as the more northerly swells peak and shift more
easterly, wrapping into exposed areas.

&&

.FIRE WEATHER...

KBDI values remain high across the state, and an overall dry
weather pattern is expected through at least Sunday over most
islands. With dry air moving overhead, relative humidity values
will have the potential to drop below the critical 45% threshold
during the late morning and afternoon hours. However, lighter
winds will mitigate fire weather concerns.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$


DISCUSSION...Almanza
AVIATION...Walsh
MARINE...Bedal