Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
804 AM EDT Wed Apr 27 2016

Valid 00Z Thu Apr 28 2016 - 00Z Thu May 05 2016

Excellent ensemble agreement remains for the central
tropical/subtropical Pacific over the next week. Upper high to the
north (sfc high to the northeast) of the region will weaken by the
weekend as an upper trough (and surface front) pass by to the
north. Trades will thus slacken amid a weaker pressure gradient
Sat/Sun. Precipitable water values will rise and fall between
about 0.75 and 1.50 inches (mostly focused between 1.00-1.25
inches) through next Tuesday as waves of moisture pass through the
state, supporting generally light precipitation on mostly windward
and terrain areas. Next week, another upper high will push
eastward past 170W which supports a surface high to the north of
Hawai'i (about 1031-1033mb per the deterministic runs), which will
increase trades again. Ensembles indicate a slight surge in
precipitable water values next Tuesday/Wednesday as the tail end
of a weak frontal boundary to the northeast sinks southward. ECMWF
was just a bit more aggressive with precipitation by then compared
to the GFS, but both were still relatively light.


Fracasso