Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
807 AM EDT Sun Mar 19 2017

Valid 00Z Mon Mar 20 2017 - 00Z Mon Mar 27 2017

Latest guidance is similar and maintains the theme of generally
moderate trades with only light and scattered rainfall focused
over windward terrain.  High pressure building to the north of the
islands Sunday-Monday will help to shift trades to a more easterly
orientation for the start of the week.  The high center will move
to the east with time while a fast moving upstream high should
reach a position north of the state by Thursday.  This high will
continue eastward as well but leave an east-west ridge axis to the
north of the islands into next weekend.  After early Tuesday
trades at some locations may become southeasterly during periods
of time when best defined high pressure is off to the northeast. 
Models and ensemble means agree in showing the strongest ridging
aloft over the state from now into Wednesday.  The ridge weakens a
bit into early Friday and then rebuilds just west/north of the
islands with an axis very close to the northwestern islands. 
Compared to yesterday there is somewhat better agreement on the
late week/weekend ridge evolution aloft.  The one notable
difference is that the 00z GEFS mean is weaker with the upper
ridge than other solutions.  There is also very good consensus
that precipitable water values should stay near average for the
time of year.

Rausch