Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
819 AM EDT Wed May 31 2017

Valid 00Z Thu Jun 1 2017 - 00Z Thu Jun 8 2017

Current water vapor imagery and model analysis indicate a
mid-level circulation northeast of the island chain while dry air
aloft filters in to the west of Hawaii.  General agreement exists
in the model guidance in lifting this cyclonic circulation slowly
to the north and dissipating over the next few days.  The ensemble
means indicate another weak trough west of Hawaii during the
Friday to Saturday time period, but it does not appear significant
enough to affect the overall weather.  Upper level ridging will
prevail through the remainder of the period as amplified flow
stays well north into the mid-latitudes.

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 second half of the forecast period, with the GEFS mean
indicating slightly lower pressures.  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 early next week, 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