Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
840 AM EDT Sun Sep 22 2019

Valid 00Z Mon Sep 23 2019 - 00Z Mon Sep 30 2019

An upper-level low currently drifting into the western outer
islands of Hawaii will continue to move west-northwest while
bringing a stream of tropical moisture northward into the main
islands of Hawaii through this week.  The moisture axis is
expected to move slowly from east to west across the main islands
during the next few days before becoming nearly stationary over
the western islands for the rest of the week.  This will likely
result in more numerous showers across the eastern islands
followed by periods of heavy rain possible over the western
islands by midweek.  A high pressure ridge at the lower levels
should slowly bring drier air from the east into the islands late
this week and into the weekend, leading to decreasing rain chances
and strengthening trade winds.  However, available moisture is
forecast to remain above normal.  As a mid-level upper low drifts
northwestward to the east and northeast of Hawaii, higher
instability would lead to an increasing chance of thunderstorms
across the area.

Kong