534
FXHW60 PHFO 270659
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
859 PM HST Wed Jun 26 2024

.SYNOPSIS...
Stable conditions under persistent breezy to locally windy trade
winds will continue through Thursday. Light showers will focus
over windward exposures. The passage of an upper level low north
of the islands from Friday through the weekend may initiate
increased shower activity and slightly increase isolated storm
chances.


&&

.DISCUSSION...
Today`s mainly dry and warm conditions will be the main theme
tomorrow, as well. The large area of anchored high pressure
centered approximately 1,000 miles north northeast of Oahu
continues to drive these ongoing breezy to locally windy trade
winds. Light showers will generally produce low rain accumulation
across more efficient convergent uplift regions such as smaller
island windward-facing mauka slopes and the Kona slopes of Big
Island. There isn`t much moisture to work with, but a shallow
early morning saturated boundary layer and afternoon warmth should
be enough to generate more areal convective coverage the next day
or so. Per local soundings, this afternoon`s convective
temperatures were in the lower 80s. In an analogous sense and
depending on the timing of higher embedded ribbons of eastern
moisture reaching us, there should be an uptick in afternoon
shower intensity and coverage as we reach those daily low to mid
80s. Higher precipitation amounts will stick to the windward mauka
slopes but an occasional more organized cell will spill over into
neighboring leeward communities.

A cut off low is developing from troughing east of the state.
Confidence is mounting that this upper low will meander northeast
of the islands Friday and then track west, or north of the area,
this weekend. Decreasing instability in association with this low
will likely enhance trade wind showers, particularly Saturday
night or early Sunday morning. Isolated thunderstorms will be
possible over Big Island slopes Friday and Saturday afternoon. The
movement of the low and its relative proximity to the islands
will ultimately determine the legitimacy of this storm threat. If
the low tracks closer to Big Island Friday into Saturday, the
coldest 500 mb temps closer to the low`s core could be the
primarily player in initiating isolated Big Island mauka storm
behavior. However, with precipitable waters forecast to be near
seasonal norms (around 1.3 inches), the amount of available
moisture will certainly be the other limiting factor (to upper
low positioning in relation to islands). After a weekend of
lessened trades in response to the north-passing upper to mid
level low, the low will exit northwest of the state Monday thus
ending any enhanced shower or isolated storm threat. High pressure
reestablishes itself north northwest of the state early next
week. This translates to a return of a traditional summertime
trade weather pattern as we go into the first full week of July.


&&

.AVIATION...
Breezy trade winds will persist across the island chain through
tomorrow. Showers and low clouds riding in on the trades will
bring brief periods of MVFR conditions over windward and mauka
locations. Otherwise, VFR conditions will prevail.

AIRMET Tango remains in effect for moderate low-level turbulence
over and downwind of island terrain due to breezy trade winds
under the tradewind inversion.

No other AIRMETs are in effect at this time. However, AIRMET Sierra
for tempo mountain obscuration may be needed again tonight if shower
coverage increases overnight.


&&

.MARINE...
High pressure north of the state will maintain moderate to at
times strong trade winds through the weekend. A Small Craft
Advisory (SCA) remains in effect for the typically windy waters
around Maui and the Big Island through 6 PM Thursday, and may be
needed at times through the weekend as winds continue to flirt
with SCA levels. The trades look to strengthen back to fresh and
strong levels early next week.

A series of south swells will keep south shore surf near the
summertime average through the weekend. Surf will drop to below
normal levels through much of next week.

A small northwest swell will fill in tonight and Thursday, and
give a slight boost to north shore surf on Friday, before fading
out over the weekend. Typical summertime conditions will continue
along north facing shores next week.

East shore surf will remain well below normal through the weekend,
then trend closer to seasonal levels next week as the trades
strengthen over and upstream of the islands.


&&

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


&&

$$


DISCUSSION...Blood
AVIATION...Farris
MARINE...Jelsema