Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
819 AM EDT Thu May 10 2018

Valid 00Z Fri May 11 2018 - 00Z Fri May 18 2018

Today's guidance shows fairly good agreement with the overall
pattern evolution but with some detail differences that could have
an influence on specifics of sensible weather.  Late this week an
upper trough passing just to the north of the state will promote
development of a surface trough over the islands, disrupting trade
flow for a couple days or so.  This feature could provide an added
focus for shower activity.  Expect highest moisture (precipitable
water values of 1.50 inches or greater) to be over the eastern
half of the state during this time frame.  High pressure building
eastward along the mid-latitudes will strengthen trade flow, with
winds likely being strongest around Sunday.  Toward the middle of
next week expect trades to become somewhat lighter as a weakness
develops aloft.  At this time there is fair amount of spread for
how much upper troughing will develop.  Of note, by Wednesday the
00z ECMWF/CMC weaken trades a little more than other solutions
that have a similar degree of upper troughing.  Then next Thursday
the ECMWF/CMC are still within the ensemble envelope but more in
the minority for the degree of upper troughing that persists,
leading to weaker trades than consensus.  Thus at that time would
recommend leaning toward the 00z/06z GFS and 00z GEFS/ECMWF means.
 From this weekend through the end of the period anticipate most
shower activity to be in the lighter half of the spectrum and
tending to favor windward locales.

Rausch