Mililani Mauka, Hawaii 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

819
FXHW60 PHFO 230122
AFDHFO

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

.SYNOPSIS...

Trade winds will continue to weaken and remain light and variable
through the weekend. With dry and stable atmospheric conditions
over the state, minimal rainfall is expected. A shallow and
dissipating front may move across portions of the island chain
Sunday night and Monday, bringing only modest showers and likely
maintaining light winds. Light to moderate trades may return by
the middle of next week.

&&

.DISCUSSION...

After a chilly start with many across the state experiencing
temperatures in the mid to upper 60s this morning (a couple of
degrees below normal for this time of year, thanks to lower than
normal dew points), most locations are approaching seasonal
normal high temperatures this afternoon. 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.

Dry and stable conditions will persist through the weekend along
with weakening trade winds as a surface high just to the north of
the state moves east and weakens in advance of a weak cold front
approaching Kauai by Sunday evening. This weaker flow is allowing
for some localized sea breezes this afternoon that will become
more prevalent across the state tomorrow and Sunday as the
background winds continue to weaken and the high clouds diminish.
Then overnight, land breezes will help to clear out low level
cloud cover over island interiors. 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 clear out across the western half of the state
tomorrow into tomorrow night and then across the eastern end by
Monday as the jet streak gradually shifts south.

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
light to moderate winds moving in behind the front, along with the
potential for a slight uptick in shower activity for the western
end of the state, but the bulk of the moisture associated with the
front should remain to the east of the island chain. Unrelated to
the front, low level tropical moisture moving in to windward Big
Island will bring a little bump in shower activity for its south
and east facing slopes from late this weekend through early next
week. 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 daytime sea breezes and night time land breezes
is expected through Saturday. Generally VFR conditions should
prevail through Saturday. There is slight chance for a few light
showers during the afternoon and evenings, which may briefly
produce MVFR conditions.

No AIRMETS are in effect. A subtropical jet will move through the
state the next several days, which could produce some light
turbulence on Saturday and some moderate turbulence Saturday night
into Sunday between FL280 and FL380.

&&

.MARINE...
Weak high pressure maintains light trades across the state this
afternoon. This high will further weaken causing trades to become
light NE to variable Saturday into early next week. Gentle to
fresh NE trades then briefly return by the middle of next week as
another weak high builds north of the area.

A small, medium period, NNE (360-020) swell has filled in today
and will increase modestly in size prior to peaking on Saturday in
support of small surf along N facing shores A moderate, medium
period pulse from the same source is expected Saturday along with
a similar size overlapping NW swell (320 degrees) which will build
on Saturday and peak during Sunday. These combined swells will
elevate surf along N and W facing shores just shy of High Surf
Advisory (HSA) criteria on Sunday before subsiding early next
week. A Marine Weather Statement remains in effect for harbor
surges, particularly at Hilo and Kahului harbor, generated by the
more northerly swells.

Surf along east facing shores will see some energy from the
northeasterly swell wrap today into the weekend. Surf along east
facing shores will become more elevated over the weekend,
especially Saturday into to Sunday as the swell peaks and shifts
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...Farris
AVIATION...Kino
MARINE...JVC