Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
213 AM EDT Thu May 6 2021

Valid 00Z Fri May 7 2021 - 00Z Fri May 14 2021

The cut-off upper low currently near 165 degrees west will very
slowly track eastward across the western Islands through the end
of the week as suggested by the ensemble means.  This will result
in an inverted surface trough and a col in the subtropical ridge
that will tend to weaken the Trades some.  This feature should
lift out as a second trough approaches from the northwest over the
weekend.  Meanwhile, a large surface high builds in across the
northeast Pacific by the end of the week and into the weekend near
140 degrees west, and this should increase the Trades some by the
weekend.  By the beginning of next week, both the GEFS and EC
means are suggesting the potential for another upper trough north
of the state.

In terms of rainfall, some enhanced showers and perhaps some
thunderstorms can be expected across the central and western
Islands by Friday and into Saturday as the upper low slowly drifts
overhead, and creates some additional instability.  Elsewhere,
typical trade wind enhanced showers can be expected, with heavier
showers likely across the Big Island.

Hamrick