Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
829 AM EDT Wed Sep 18 2019

Valid 00Z Thu Sep 19 2019 - 00Z Thu Sep 26 2019

This coming week upper-level ridging will drift toward/past the
region, which will lead to light windward showers and an increase
in trade winds. Model guidance shows multiple tropical
disturbances will pass near/south of the Islands. The first is a
pair of lows that merge along and near 170 west and lift
northward. The second drifts south of the state on the 21st and
the third is Tropical Storm Kiko which will reach 140W by the end
of the forecast period.

By this weekend, an upper low will move in from the west
underneath an upper high in the mid-latitudes, bringing an
increased chance of rain. The 00Z ECMWF and its ensembles continue
to be quicker than the 00Z/06Z GFS and its ensembles, but both
systems show an increase in moisture as surges peel off the ITCZ.
A compromise of the ECWMF and GFS provide a middle-ground solution.

Campbell