Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Honolulu HI
830 PM HST Friday Jul 29 2016

Synopsis...
a surface high to the north will keep trade winds blowing over the
islands through the coming week. The trades will carry areas of
tropical moisture over the islands while a passing low aloft will
make the atmosphere more unstable over the next several days.
This combination will keep the weather Rainier than normal over
much of the next week.

&&

Discussion...
a 1033 mb surface high 1750 miles north northeast of Honolulu at
44n144w will move slightly to the west with little change in
strength through tomorrow. The pressure gradient southwest of the
high will keep breezy trade winds blowing over the main Hawaiian
islands tonight.

Water vapor imagery shows a low aloft 675 miles east northeast of
Honolulu at 26n149w moving toward the west northwest around 15 mph.
As this low moves by the islands tonight 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.
An east northeast to west southwest band of showery low clouds is
moving over the islands, mainly over Kauai County and Oahu. This
band is associated with a surface trough induced by the low aloft.
There may be moisture from former Hurricane Georgette within the
band. The cloud band will bring showers to Kauai and Oahu through
the night and may spread down over Maui County and The Big Island
tomorrow.

As the low aloft moves north away from the islands next Tuesday, the
trade winds will become breezy again. An area of tropical moisture
enhanced by the low aloft will help boost shower activity through
early next week. A bigger increase in showers is likely Thursday
when another area of tropical moisture moves over the islands.
Showers may increase again over the following weekend as more
tropical moisture moves over the islands from the east and a low
aloft digs south and destabilizes the atmosphere.

&&

Aviation...
airmet Tango for low level turb over and S through west of the
mountains remains posted as breezy NE to east trade winds continue.
VFR conditions will prevail, but windward areas may experience
isolated MVFR ceilings.

&&

Marine...
a high to the northeast will maintain fresh to locally strong trade
winds across the area tonight. A Small Craft Advisory (sca) is in
effect for the windy zones around Maui County and The Big Island
tonight. Winds will weaken tomorrow as a surface trough moves over
the area from the east. We may be able to drop the Small Craft Advisory this weekend.
The trade winds will strengthen again by the middle of next week.

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

&&

Hfo watches/warnings/advisories...
Small Craft Advisory until 6 am HST Saturday for Maalaea Bay, the
pailolo and alenuihaha channels and waters south of The Big Island.

&&

$$
Donaldson

National Weather Service Glossary of Abbreviations