Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
817 AM EDT Sat Jun 25 2016

Valid 00Z Sun Jun 26 2016 - 00Z Sun Jul 3 2016

Over the next 7 days, a sprawling 1034 mb high near 40N is
expected to gradually weaken by the middle of the week to around
1028 mb as a strong upper level ridge is slowly eroded.  This will
be the result of troughing over the northern Pacific dropping
southward, effectively shrinking and weakening the ridge.  This
trough should slowly retrograde westward across the islands
through midweek.  Towards the end of the week, a strong upper low
moving across the Aleutians continues to effectively keep the
ridge from growing as well, with the 6Z GEFS mean showing a
stronger system.  The surface pressure pattern over the state is
in relatively good agreement between the 6Z GEFS mean and the 00Z
EC mean.

The result in terms of sensible weather will be east-northeast
trades with little fluctuation in wind direction during this time.
 Precipitable water values increase to slightly over 1.5 inches by
Wednesday as the upper level trough axis moves by, with heavier
showers likely.  Besides that, the typical orographically enhanced
shower activity on the windward slopes can be expected.

Hamrick