Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
209 AM EDT Thu Jul 23 2020

Valid 00Z Fri Jul 24 2020 - 00Z Fri Jul 31 2020

...Tropical Cyclone Douglas forecast to reach Hawaii as a
weakening hurricane or tropical storm this weekend...

The most significant aspect of the forecast for Hawaii continues
to be now Hurricane Douglas across the eastern Pacific, which is
forecast by the National Hurricane Center to reach Hawaii on
Sunday as either a weakening hurricane or a strong tropical storm.
Consensus among ensemble members around the forecast track remains
quite good, but small variations in the track, farther north or
south, could have a significant effect on the expected impacts for
specific locations/islands. Potential impacts from Douglas include
strong, gusty (tropical storm or hurricane force) winds as well as
very heavy rainfall, which could begin as early as Saturday night
or Sunday morning. Several inches of rainfall are possible.
Ensemble guidance continues to suggest the greatest potential for
the heaviest rains across the Big Island, but heavy rains will be
possible across any islands that are close to the eventual track
of the system. The system should continue to gradually weaken as
it moves westward, and should move away from Hawaii on Tuesday. In
the wake of Douglas, expect a resumption of a trade wind pattern,
with advection of a somewhat drier air mass across the state, and
light to moderate trades through late next week.

Ryan