Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
826 AM EDT Sat Jun 15 2019

Valid 00Z Sun Jun 16 2019 - 00Z Sun Jun 23 2019

An elongated high pressure ridge, both at the surface and aloft,
is expected near 30N this weekend across the central Pacific.  The
high builds to the northeast of Hawai'i by Monday as a col
develops within the ridge axis owing to a large scale trough
dropping southward from the Aleutians.  An inverted surface trough
develops in the general vicinity of 165W early in the week in
response to the building upper level trough, supporting a
quasi-stationary frontal zone to the northwest of the state.  This
feature is not expected to move very much through the end of the
week according to the ensemble means, with the EC mean and the 00Z
ECMWF more amplified with this compared to the GEFS mean and 6Z
GFS.

Easterly trades will likely increase slightly through the rest of
the weekend, followed by lighter east-southeast flow in response
to the building trough northwest of Hawai'i.  The boundary does
not appear strong enough to advect deep moisture northward from
the ITCZ, with PWs generally staying near or below 1.5 inches for
this forecast period.  Most shower activity will be confined to
windward facing terrain.

D. Hamrick