Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
823 AM EDT Thu Jun 1 2017

Valid 00Z Fri Jun 2 2017 - 00Z Fri Jun 9 2017

Current water vapor imagery and model analysis indicate a
weakening mid-level circulation northeast of the island chain with
another weak mid-level disturbance well to the west.  General
agreement exists in the model guidance in gradually dissipating
both of these weak systems with upper level ridging becoming
firmly established by the beginning of next week and then
remaining in place.  The axis of the ridge should be centered
between 25 and 30 degrees north.

At the surface, an elongated high pressure ridge is forecast to
prevail through the entire forecast period centered mainly along
35 degrees north.  The core of the high is expected to move to the
northeast of the state by Sunday.  Both the GEFS mean and EC mean
are indicating a cold front passing by well to the north of Hawaii
and thus breaking down the western extent of the ridge some during
the Tuesday to Wednesday time period, perhaps weakening the trades
some.  The surface high is forecast to build back in place by next
Thursday.  Regarding precipitation, the usual trade driven shower
activity is likely.  Although the 6Z GFS is indicating a slight
increase in QPF over the western portion of the islands on Sunday,
no major rainfall events appear likely on the horizon. 
Precipitable water values throughout the forecast should generally
average around 1.25 inches with higher moisture content being
suppressed toward the Intertropical Convergence Zone.


Hamrick