Current Conditions
Temp8.6 C
RH9 %
WindNE 10 mph
RoadOpen (4x4)
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Hawaiian Islands Synoptic Discussion and Guidance

713
FXHW60 PHFO 281940
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
940 AM HST Wed Jun 28 2017

.SYNOPSIS...
Breezy trade winds associated with high pressure north of the state
will continue through Friday, before slightly trending down over
the upcoming weekend. Dry and stable conditions will limit shower
activity over the state through Thursday. Showery weather will
become more likely beginning Thursday night and continuing through
the weekend. Windward and mountain areas will be the focus for
most of the shower activity.

&&

.DISCUSSION...
Upper level ridging over the state is supporting continued dry
and stable conditions aloft this morning. A near typical inversion
height around 6 to 7 thousand feet is keeping clouds and showers
limited in areal extent. These mainly dry conditions are expected
to continue statewide in the short term as the surface trade wind
flow remains in place due to the persistent surface ridge far to
the north. Limited moisture riding along in these trade winds
supports a forecast of mainly sunny and breezy conditions today.

For tonight and Thursday, little change in conditions is depicted.
However, on Thursday night, all of the more reliable model
guidance is showing an increase in moisture moving across the
state from the northeast and east. Thus, there is an increasing
likelihood for showery weather to return, especially windward and
mountain areas. The trades will be strong enough for some of the
showers to reach leeward areas as well. These wetter trade wind
conditions will likely continue into the weekend. There will
probably be daily variations in the shower distribution and trade
wind fluctuation, but for now will keep a generally wetter trend
in the forecast, which can be refined as the time approaches.

On Monday, the guidance is in agreement showing a batch of drier
and more stable air moving over the state in increasing trades,
thus giving our area breezy conditions, with locally strong gusts
as high pressure remains north of the state.

&&

.AVIATION...
Fresh to locally strong trade winds will continue today. AIRMET
TANGO remains posted for low level turbulence over and immediately
south through west of the mountains. Morning soundings show a
strong low level inversion between 6-7 kft. The elevated wind
speeds and a stable atmosphere will help support the formation of
mountain waves downstream of the ranges.

Any cloud build ups and isolated showers will favor the windward
and mountain areas. Expect prevailing VFR conditions across the
islands today. Some passing clouds and showers may bring brief
MVFR conditions, mainly CIGS due to low stable clouds.

&&

.MARINE...
The Small Craft Advisory (SCA) includes the Kaiwi Channel, Maui
windward waters, Oahu leeward waters, the typical windy zones
around Maui and the Big Island. The SCA is in effect through
Thursday, and may continue for some zones into Friday, followed by
slightly weaker trade winds this weekend.

The locally strong trades will produce choppy surf along east
facing shores through the rest of the work week. A small short-
period northwest swell is also forecast from Friday into this
weekend.

Small pulses of swell energy from the southeast through southwest
will continue bringing near normal summertime surf along south
facing shores. Reinforcing long-period south swells will generate
a slight bump in surf heights from Thursday into the weekend.

&&

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


&&

$$

Discussion...Brenchley
Aviation...Eaton
Marine...Foster

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