949
FXHW60 PHFO 141347
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
347 AM HST Sun Jul 14 2024

.SYNOPSIS...
A large area of high pressure generally north of the Hawaiian
Islands will hold through early Monday. This will maintain the
ongoing typically dry summertime trade wind pattern. Windward and
mauka area light showers will primarily occur during the early
morning and overnight hours. A vicinity upper level disturbance
developing northeast of the state Monday will weaken mid to late
week winds to more gentle speeds and increase island-wide rain
chances.


&&

.DISCUSSION...
There remains little variance in forecast philosophy under this
near static Central Pacific synoptic pattern. Stable conditions
will stay in play as a result of ridging anchored north of the
state. Summertime dry trades will hang on for another day as a
pair of surface highs centered northwest and northeast of the
islands drive these stubborn breezy easterlies. Relatively lower
inversion near 5k ft foot heights will result in a regional
shallow boundary layer as evidenced by this morning`s lower level
stratocumulus and quiet radar. Somewhat dry mid to upper level
moisture (30% to 40% RH) advecting in across the chain has bets
hedging toward a stable enough island environment that will
generally support more windward area and mauka clouds with showers
focused on the higher elevations. The usual caveats still apply of
cloudier, slightly more wet afternoon Kona and Ka`u slope
conditions with infrequent leeward short-lived light showers and
partly cloudy skies riding over local area ridge tops.

The development of an upper level disturbance forming in the
middle of the northern ridging tomorrow will be the impetus to
gradually weakening trades. The surface reflection of weak
troughing, along with the proximity of the subtropical jet, may
work in favor of increasing more areawide pockets of better
organized shower activity through the week. The main question
marks to latter week increased shower activity relieving us from
this recent dry spell will be whether or not there will 1) be
ample column moisture within a deepened, marginally-destabilized
boundary layer and 2) the location of the upper disturbance in
relation to the islands. The wettest period is shaping up to be
later in the week, Thursday and Friday. Late week inversions are
progged to be slightly higher, lower level lapse rates the
greatest within a more moist air mass. These three elements best
come in-line over Big Island and Maui Counties as we close out the
week.


&&

.AVIATION...
Breezy to locally windy trades will continue over the next few
days. SHRA amd low cigs will favor windward and mauka locations
with a few SHRA making it leeward. Some brief MVFR conds are
possible in SHRA, otherwise VFR conds should generally prevail.

AIRMET Sierra is in effect for mtn obsc for N through SE sections
of the island chain. Low cigs and a slight increase in SHRA are
expected through the night into the morning hours.

AIRMET Tango for mod low-level turb lee of terrain is in effect
and will likely be needed for the next several days due to the
strong trades under a strong inversion.


&&

.MARINE...
A strong high pressure ridge remains north of the islands, and
will continue to drive fresh to locally strong trade winds into
Wednesday. The Small Craft Advisory (SCA) for all Hawaiian Coastal
Waters will remain in effect through Monday. This SCA will
decrease in coverage after 6 AM HST this morning to the typical
windier waters near Maui County and the Big Island.

The current long period south swell continues to fill in and a
High Surf Advisory remains in effect for the south facing shores
of all islands through Monday. West facing shores will see a
decent south swell wrap, boosting surf heights as well, with the
Big Island west facing shores forecast to remain just below HSA
levels through Monday. A gradual downward trend in south swell
activity is expected Tuesday through midweek.

Due to the strong trade winds upstream of the state, surf along
east facing shores will remain rough and choppy through Tuesday.
A downward trend is possible by Wednesday as the upstream fetch
weakens and the local trades begin to ease.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory until 6 PM HST Monday for Niihau-Kauai
Leeward-Waianae Coast-Kahoolawe-Maui Leeward West-Kona-Kauai
South-East Honolulu-Honolulu Metro-Ewa Plain-Molokai Leeward
South-Lanai Leeward-Lanai South-Maui Central Valley South-South
Maui/Upcountry-South Haleakala-Big Island South-Big Island
Southeast.

Small Craft Advisory until 6 AM HST early this morning for Kauai
Northwest Waters-Kauai Windward Waters-Kauai Leeward Waters-
Kauai Channel-Oahu Windward Waters-Oahu Leeward Waters-Kaiwi
Channel-Maui County Windward Waters-Maui County Leeward Waters-
Big Island Windward Waters.

Small Craft Advisory until 6 PM HST Monday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.


&&

$$


DISCUSSION...Blood
AVIATION...Walsh
MARINE...Bohlin