Heavy Rain in Hawaii, July 8, 2021

Area Forecast Discussion
National Weather Service Honolulu HI
359 PM HST Thu Jul 8 2021

.SYNOPSIS...
Expect a light trade wind pattern with localized sea breezes
across leeward areas during the day, followed by night time
clearing. Rainfall amounts will be light. Trade winds will ramp
back up by Sunday, reaching breezy levels once again through next
week.

&&

.DISCUSSION...
Radar and satellite loop shows scattered showers across leeward
areas of most of the state this afternoon. As we head into the
evening hours, we should see these showers dissipate with a light
trade/land breeze flow expected overnight tonight. For Friday, we
should see a similar day to today, with mostly sunny skies in the
morning, followed by afternoon cloud build ups and light showers
over leeward and interior areas during the afternoon.

Breezy easterly trades will begin filling in from east to west
late Saturday and we should see 15-20 mph trades across the state
by Sunday. Scattered showers will once again be focused over
windward areas and we should continue to see this pattern through
early next week. A brief increase of trade wind showers are
possible late Sunday into Monday as a weak trough passes near the
state. By middle of next week, we are expected a strong high
building far north of the state and that should cause the trades
to return to a more east-northeast direction. Breezy trades are
expected to continue through next week.

&&

.AVIATION...
Surface high pressure located far northwest of the islands will
maintain mostly moderate trade winds through Friday. Satellite
imagery shows widely scattered patches of low clouds with embedded
light showers favoring the windward and mountain areas, as well as
upstream. Brief periods of MVFR ceilings with these clouds are
expected. The background trade flow will be light enough to allow
localized sea breeze development, resulting in some spotty clouds
and a possible shower over some interior and leeward areas this
afternoon and into the evening. Expect similar conditions Friday
as well. No AIRMETS are currently in effect, nor expected through
Friday.

&&

.MARINE...
A broad surface trough passing N of the islands will keep trade
winds veered slightly to the E for the next couple of days, while
wind speeds will also be somewhat subdued. As the trough moves W
to a position NW of the islands over the weekend, trade wind
speeds will increase Saturday, and then back to a more typical ENE
direction as they increase further on Sunday. Locally strong
trade winds are then expected to continue into early next week. A
Small Craft Advisory will likely be necessary for the windier
zones around Maui and the Big Island beginning Saturday.

Surf will remain below High Surf Advisory levels along all shores
into next week, as a recent long-lived S swell continues to
diminish. The increased trade winds will bring an increase in
short-period wind waves along E facing shores over the weekend and
early next week, but significant surf is not expected. Another S
swell is possible in just about a week, generated by several lows
in the S Pacific.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
None.

&&

DISCUSSION...Kino
AVIATION...TS
MARINE...Birchard