Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
820 AM EDT Wed Jul 5 2017

Valid 00Z Thu Jul 6 2017 - 00Z Thu Jul 13 2017

The large mid-level subtropical high that is northwest of the
Islands today is forecast to remain in place through the end of
the week and then to gradually build and expand eastward around 35
degrees north per the latest ensemble means.  There is a greater
signal in the guidance of a tutt low at 250mb just south of the
ridge axis between 25 and 30 degrees north that will serve to
increase westerly wind in excess of 50 knots at 250mb by the
middle of next week.  At the surface, a trough located northeast
of the state will relax the pressure gradient some before the
surface high becomes strongly dominant by Tuesday.

This high will support fairly brisk trades through the period with
the strongest winds likely to be through Thursday, and again early
next week as the high builds to the north.  Expect precipitable
water values to be near 1.25 inches with minor fluctuations
through Sunday night.  There is still the potential for an axis of
enhanced moisture to reach the Islands around Tuesday and
Wednesday of next week.  On average expect windward favored
showers, with some local enhancement early next week as
precipitable water increases.  However, the greatest QPF should
remain well to the south of the state where the ITCZ is most
active.

Hamrick