Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
816 AM EDT Sat May 12 2018

Valid 00Z Sun May 13 2018 - 00Z Sun May 20 2018

Expect trades to freshen heading into Sunday as high pressure
tracks well north of the state.  Winds will then gradually trend
lighter as the high continues northeastward and weakens.  Guidance
is consistent in depicting lightest trades around Wednesday as a
weak upper trough develops over the area and a cold front passes
by to the north.  Winds will strengthen again later in the week as
heights aloft rise and another mid-latitude surface high passes
by.  Even though models/means show high pressure reaching the
eastern Pacific by Saturday, trades of similar strength should
persist at that time as the high still extends a ridge
west-southwestward.  Through the period shower activity will
likely favor windward terrain and be on the lighter side.  Aside
from the northern fringe of a moisture pocket possibly brushing
the Big Island Saturday night, precipitable water values should be
near to below average for the time of year through at least
Wednesday.  Guidance still shows a small area of greater moisture
reaching the eastern islands late in the week.  The ECMWF is still
a little earlier than other solutions to varying degrees but there
is general agreement that drier air should return around Saturday.

Rausch