Area Forecast Discussion
Issued by NWS Honolulu, HI

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FXHW60 PHFO 290633

Area Forecast Discussion
National Weather Service Honolulu HI
830 PM HST THU JUL 28 2016

A high to the north will keep trade winds blowing over the islands.
The high will be strong enough to make the trades breezy through
tomorrow. A dry, stable atmosphere will keep rainfall sparse for the
next 24 hours. The trade winds will weaken and showers will become
more active starting tomorrow night as a low aloft approaches from
the east.


A 1032 MB surface high 1650 miles north northeast of Honolulu at
41N142W will move northwest slowly with little change in strength
through Friday evening. The pressure gradient southwest of the high
will keep breezy trade winds blowing over the main Hawaiian Islands
through Friday evening. The atmosphere over the islands is dry and
stable. Balloon soundings at 200 PM showed strong temperature
inversions near 4500 feet at Lihue and near 6000 feet at Hilo. These
inversions will limit cloud growth and keep rainfall light through
the day on Friday.

Water vapor imagery shows a low aloft 820 miles east northeast of
Honolulu at 24N 146W moving toward the west northwest around 20 mph.
As this low moves by the islands Friday night through early next
week, it will weaken the trade winds and raise the temperature
inversions. The higher inversions will mean that showers will become
more active.

As the low aloft moves north away from the islands next Tuesday, the
trade winds will become breezy again. Moisture from the remnant of
Hurricane Georgette will likely spread over the islands during the
second half of the week, so the weather may remain wetter than usual
for July.


AIRMET TANGO remains in effect for low level turb over and S through
W of the mountains. The 200 PM soundings showed a strong inversion
sloping from 6200 feet at Hilo to 4300 feet at Lihue while the VAD
wind profiles show 20 to 30 kt winds in the lower atmosphere.
VFR conditions will prevail, but windward areas may experience
isolated MVFR ceilings.


A high to the northeast will maintain strong to near-gale force
trade winds across the area through Friday. A Small Craft Advisory
(SCA) is in effect for all Hawaiian waters through Friday afternoon.
Winds will taper off as a weak surface trough arrives from the east
Friday night into Saturday. Some or all zones may drop out of the
SCA this weekend.

The trade winds will produce choppy surf along east facing shores,
but surf is expected to remain below advisory levels. There will be
a series of small south swells into next week but surf will remain
below the advisory level along south facing shores also. Only small
surf is expected along north and west facing shores.


Small Craft Advisory until 6 PM HST Friday for all Hawaiian


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