Area Forecast Discussion
Issued by NWS Honolulu, HI
FXHW60 PHFO 282009
Area Forecast Discussion
National Weather Service Honolulu HI
1009 AM HST THU JUL 28 2016
Breezy trade wind weather will persist through the work week as
high pressure builds far to our north. Trades are forecast to
decrease slightly this weekend as an upper low and associated
weak surface trough approaches from the east. Clouds and showers
will favor windward and mauka areas, but may become more active
this weekend through early next week.
A 1030 MB surface high is located at 40N141W is driving fresh to
strong trade winds across the state this morning. Satellite shows
a broad field of stable stratocumulus clouds carrying in with the
trades extending east from the islands all the way to the
mainland. These stable clouds are occasionally brushing against
the windward slopes, bringing partly to mostly cloudy skies this
morning, but are producing little rainfall. Leeward areas are
mostly sunny with the exception of the Kona slopes on the Big Island.
Early morning soundings show strong inversions between 5500 and 6500
feet, with near-seasonal precipitable water values around 1.3
inches. In the short term, expect stable and breezy conditions to
continue with little rainfall carrying in with the trades.
An upper low and associated weak surface trough will approach from
the east on Friday. The trades may strengthen slightly and back
northeasterly ahead of the surface trough on Friday. This weekend,
an increase in low level moisture is expected to arrive as the
trough axis moves by with weakening and veering winds. This will
result in a wetter trade wind pattern from this weekend into early
next week. Clouds and showers will still favor windward and mauka
areas, but leeward areas will see more showers than they do now.
AIRMET TANGO for low level turb over and S through W of the
mountains remains posted as breezy NE to E trade winds continue.
The 12Z soundings from PHTO and PHLI show a strong inversion
sloping from 6.2 kft to 5.0 kft, respectively.
Expect primarily VFR conditions throughout the islands today. The
relatively dry atmosphere and strong inversion will help keep
showers at a minimum. A large area of stable stratocumulus extends
from the coast of California to near Hawaii. The breezy trade
winds will help carry these low stable clouds towards the islands
and windward areas may experience isolated MVFR cigs.
High pressure far northeast of the state will strengthen and shift
westward, which will maintain breezy trade winds across the area.
The Small Craft Advisory is in effect for all Hawaiian waters
through Friday afternoon.
The trade winds will result in choppy, short-period surf along
east facing shores, but surf heights are expected to remain below
advisory levels. There will also be a series of small southerly
swells through the weekend and into next week.
Small Craft Advisory until 6 PM HST Friday for all Hawaiian