Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Honolulu HI
330 am HST sun Jul 5 2015
trade winds will gradually increase through the first half of next
week as the governing ridge strengthens to our north. Rather dry
conditions will transition to a more typical trade wind
pattern...with clouds and showers favoring windward and Mauka
areas...next week as trade winds increase.
surface troughing between 160w and the dateline has begun to
ease...allowing the pressure gradient to begin to steepen across the
main Hawaiian islands this morning. The result is slightly stronger
prevailing easterlies across local waters but continued overall
light winds across the islands themselves. Satellite loop shows low
cloud cover advecting into windward areas of Maui and The Big
Island. Otherwise...cloud cover is sparse across the smaller
islands. Overnight soundings show our airmass remains more moist and
unstable toward the western end of the island chain...closer to the
troughing west of the islands. However...a subsidence inversion has
formed over Lihue as ridging begins to take hold. Radar shows very
little shower production across the area.
Models show the troughing west of the islands will completely lift
out to the north by early next week...allowing the ridge to our
northeast to rebound westward. This will steepen our local pressure
gradient and increase trade flow across the area. The rather dry
conditions across the area this evening will gradually transition to
a trade wind pattern...with clouds and showers favoring windward and
Mauka areas...through the first half of next week as the ridge
strengthens and trade winds increase. Trade winds will continue to
strengthen into the second half of next week...causing leeward areas
to get wet as well from time to time as showers are blown across the
The Central Pacific Hurricane Center in Honolulu and the National
Hurricane Center in Miami are monitoring a couple of areas of
disturbed weather over the east Pacific. These areas will continue
to be closely monitored for any signs of development.
trade winds are expected to increase as the high to the north of the
state builds. Expect clouds to increase this afternoon with only
isolated showers due to a dry airmass over the islands. More typical
clouds and showers over windward areas are expected tomorrow. VFR
conditions are expected.
winds and seas are expected to remain below Small Craft Advisory
levels through Wednesday. However...seas will build toward the end
of the forecast period due to the stronger trade winds.
A high surf advisory is in effect along south facing shores through
this afternoon. This swell will lower gradually this evening through
Tuesday. A series of small to medium size south swells are expected
through the remainder of the forecast period. A small northwest
swell is expected to linger over the weekend and on into the middle
of next week. Strengthening trade winds will cause short period
choppy surf to increase next week.
high surf advisory until 6 PM HST today for Niihau-Kauai
windward-Kauai leeward-Oahu South Shore-Waianae coast-Molokai-
Lanai makai-Kahoolawe-Maui leeward west-Maui Central Valley-
windward Haleakala-leeward Haleakala-Kona-south Big Island-Big
Island north and east-kohala.