Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
830 AM EDT Tue Oct 08 2019

Valid 00Z Wed Oct 09 2019 - 00Z Wed Oct 16 2019

The model guidance is in pretty good agreement over the course of
the next week depicting a subtropical high aloft passing north of
Hawaii from east to west.  Meanwhile, moisture from a couple of
tropical waves will begin to head toward Hawaii as an upper-level
is forecast to develop to the northwest of the island chain.  This
pattern will guild moisture from the tropical waves gradually
across much of Hawaii from east to west for the latter of this
week into the weekend.  Meanwhile, wind directions will slowly
veer from easterly to east-southeasterly with time as a high
pressure ridge in the lower levels build in from the east.  This
will favor a high chance of heavy rainfall along the east- and
southeast-facing slopes, especially for the Big Island. Model
precipitable water values reach over 2 inches across the island of
Hawaii by late Wednesday, then overspread the remainder of state
Thursday into Friday.  By Sunday, drier air from the surface ridge
should be pushing across much of Hawaii and rain chances will
decrease.  The drier conditions should persist through next
Tuesday.

Kong