Current Conditions
Temp8.9 C
RH29 %
WindS 8 mph
RoadOpen (4x4)
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Hawaiian Islands Synoptic Discussion and Guidance

FXHW60 PHFO 162012

Area Forecast Discussion
National Weather Service Honolulu HI
1012 AM HST Sun Jun 16 2019

Fresh trades will continue today with mostly dry and stable
weather. Winds will shift slightly southeast for Monday and
Tuesday, and back easterly for Wednesday and Thursday. Clouds and
showers will focus across windward and mauka areas and remain
mostly light.


A 1026 mb surface high is centered far northeast of Hawaii driving
fresh trade winds across most of the state this morning. 12Z
soundings show strong atmospheric stability with an inversion near
6000 feet at Lihue to 8000 feet at Hilo. Visible satellite shows
mostly sunny skies over most of the state with some low cloud build
ups on windward Kauai and Oahu, and the lower slopes of the Big
Island to a lesser extent. Radar shows very little, if any,
precipitation falling. Expect a warm and pleasant condition for
the rest of today. Late tonight, a few more clouds and showers
will move in the trade wind flow and may impact windward sections
of Maui and the Big Island.

A longwave trough is positioned across the North Central Pacific
and to the northwest of Hawaii. A surface reflection of the trough
is located west of our area and will begin to strengthen and develop
tonight and Monday. While this activity will not directly impact
our area, we are expected to see a subtle shift in wind direction
to slightly south of due east for Monday and Tuesday. Wind speeds
should remain moderate to fresh, but blocking downstream may
weaken winds for leeward areas particularly across Kauai and Oahu.
Scattered clouds and showers will remain focused windward and may
increase Monday into Tuesday. Rainfall amounts will be on the
light side.

Wednesday and Thursday, the surface high northeast of the state
will push back winds easterly, bringing in more typical trade wind
weather. A repeat of the the developing trough to our west will
repeat Friday with a more dramatic shift to southeast winds into
next weekend.


Surface high pressure will remain to the northeast of Hawaii,
providing moderate to locally strong trade winds to the area
through tonight. Passing low clouds and isolated showers will
affect windward and mountain areas of the islands at times. Mainly
VFR conditions will prevail, though windward and mountain areas
may see brief MVFR ceilings/visibility.

No AIRMETS are expected today, though will continue to monitor the
potential for AIRMET Tango for low-level turbulence continues due
to the rather robust trade winds.


High pressure far northeast of the state will maintain fresh to
locally strong trades through the middle of the week. Winds may
veer east-southeasterly Monday into Tuesday as a weak trough
develops far west of the state. A Small Craft Advisory (SCA) is in
effect for the typically windy waters around the Big Island and
Maui through early Monday morning. This will likely need to be
extended at least into Tuesday.

Surf has dropped some along south facing shores today, but is
still holding at levels slightly above the summer average. We
should continue to see a gradually drop of the south-southwest
swell into Monday. A new small long-period south-southwest swell
is expected to fill in on Tuesday and peak on Wednesday with
heights around the summer average. Surf heights are expected to
stay below advisory levels for the foreseeable future along south
facing shores.

A reinforcing northwest swell will continue to produce surf in
the small to moderate range along north facing shores through
today. Additional pulses of tiny northwest swell are expected
through the week. Also, surf along east facing shores will begin
to rise early this week as trade winds become more established.


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




Bulletins, Forecasts and Observations are courtesy of Honolulu National Weather Service Forecast Office