416
FXHW60 PHFO 221928
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
928 AM HST Fri Nov 22 2024

.SYNOPSIS...

Trade winds will weaken today and become light and variable
during 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 trades may return by the middle of
next week.

&&

.DISCUSSION...

After a slightly 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
our lower than normal dew points), most locations are expected to
reach seasonal normal high temperatures this afternoon.

Dry and stable conditions will continue 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 will allow
for localized sea breezes today that will become more prevalent
across the state tomorrow and Sunday as the background winds
continue to weaken. With the 12Z upper air soundings at Lihue and
Hilo both showing strong temperature inversions between 4,000 and
5,000 feet and precipitable waters values less than an inch early
this morning, these dry and stable conditions will limit any
shower development. Then overnight, land breezes will help to
clear out cloud cover over island interiors. Dew points will
remain in the lower to mid 60s across most locations, allowing
overnight lows to stay a few degrees below normal through the
weekend and keeping afternoons pleasant with lower relative
humidity values. In addition, high clouds will stream in from the
west today through tomorrow as a weak jet streak develops aloft.

According to the latest model guidance, a weak cold front will
approach Kauai`s doorstep Sunday night, then dissipate as it
gradually moves towards Oahu and Maui County on Monday and
Tuesday. Impacts look to be minimal with light to moderate
northerly winds moving in with 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.

Forecast details become a bit murkier Tuesday into Wednesday as
the front dissipates across the area and models hint at a second
weak front approaching from the northwest. However, even with the
model discrepancies regarding this potential second front, high
pressure will build north of the state on Wednesday, then move
eastward on Thursday and bring a return to light to moderate
easterly trades heading into the latter part of the week.

&&

.AVIATION...

A gentle trade wind flow is expected today with localized sea
breezes developing by late morning. Clouds will gradually increase
throughout the day, but generally VFR conditions should prevail.
A few light showers will be possible in the afternoon, which may
produce brief MVFR conditions. Land breezes will begin to develop
during the evening which should decrease any shower activity.

No AIRMETS are in effect and none is anticipated during the day
today.

&&

.MARINE...

Weak high pressure maintains light trades across the
state this morning. 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 swell (010-030 degrees) is filling at
CDIP Hilo and Pauwela near shore buoys this morning. This should
produce some small surf along N facing shores today. A moderate,
medium period pulse from the same source is expected Saturday
along with a similar size overlapping NW swell (320 degrees).
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