809
FXHW60 PHFO 270156
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
356 PM HST Fri Jul 26 2024

.SYNOPSIS...

A strong high pressure system north of the Hawaiian Islands is
gradually weakening. Trade wind speed trends will decrease to the
moderate to breezy range tonight into Sunday, and then to
moderate levels from Monday onward and the high continues to
weaken. Strong and stable subsidence aloft will limit shower
potential for most days into next week. However, a slight increase
in cloud and shower trends may develop later tonight through
Saturday as a weak easterly wave moves from east to west down the
island chain.

&&

.DISCUSSION...

The pressure gradient over the state has weakened and trade wind
speeds are on a decreasing trend. Scattered clouds with isolated
showers embedded in the trade wind flow will focus along windward
and mauka regions. Models continue to show a subtle low level
trough moving from east to west across the island chain tonight
through Saturday. This could elevate inversion heights enough
allowing for increasing shower trends, mainly over windward and
mountain areas with some spillage to leeward areas of the smaller
islands. However, total precipitable water values locally and
upstream will remain near to below average so this may put an
upper limit on rainfall totals.

The high far north of the state will continue to gradually weaken
into next week resulting in a decreasing wind speed trend. Trades
are expected to become moderate to breezy Saturday to Sunday,
before further weakening to more moderate levels Monday onward.
Some of the more wind favored areas may see brief periods of
locally breezy wind speeds next week. Can expect stable and mostly
dry weather trade wind weather through the rest of the forecast
period. Strong and stable subsidence under an upper level ridge
will continue to limit vertical cloud heights and shower
development into much of next week as well as near to below
average precipitable water values.


&&

.AVIATION...

Breezy to locally windy trade winds will remain through tonight
and slowly decrease in strength starting tomorrow. Clouds and
showers will focus primarily over windward and mountain areas with
enhanced showers during the overnight hours. MVFR ceilings and
visibility can be expected in any showers. Overall VFR conditions
will likely prevail.

AIRMET Tango remains in effect for moderate low-level turbulence
for areas downwind of island terrain and will likely be needed
through tomorrow.


&&

.MARINE...

Strong surface high pressure far northeast of the state will
maintain locally breezy trades through this weekend. The Small
Craft Advisory has been scaled back to just the typical windier
areas around Maui County and the Big Island through Saturday
evening. By early next week, the aforementioned high is forecast
to move further west and allow trades to ease into the gentle to
fresh range.

Near shore buoys continue to indicate a small, medium to long
period south swell, which will provide small surf for south
facing shores through Saturday. By mid to late next week, another
small long period, south southwest swell should bring a slight
bump up in surf along the south facing shores.

The enhanced trades will continue to produce rough and choppy
surf for the east-facing shores through this weekend. Local wind
swell may wrap into select north and south facing shores.
Surf along north facing shores will remain nearly flat, typical
of this time of year.


&&

.FIRE WEATHER...
Gusty trade winds and low relative humidity will keep elevated
fire weather concerns into the weekend. Windier trade wind areas
and downslope leeward locations such as West Maui and leeward
Kohala on the Big Island are of particular concern moving forward.
Trade winds will gradually ease into the moderate to breezy range
Saturday to Sunday, and then down to moderate levels from Monday
onward as the pressure gradient over the state relaxes.

Most leeward areas will remain dry. Brief periods of showers will
move into windward areas mainly in the overnight hours. Humidity
levels will see good to excellent overnight recoveries. Exceptions
to this humidity rule will be for elevations in the 4,000 to
8,000 foot range, which may see periods of warmer temperatures
with much drier conditions, within and above the subsidence
inversion level.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST Saturday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.


&&

$$


DISCUSSION...Almanza
AVIATION...Tsamous
MARINE...Thomas