Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
851 AM EDT Tue Sep 11 2018

Valid 00Z Wed Sep 12 2018 - 00Z Wed Sep 19 2018

Tropical storm Olivia has weakened over the past 24 hours but will
still keep a westerly track toward the Hawai'ian islands.  The
center of Olivia will move near Maui late Tuesday night into
Wednesday morning. There is still some timing differences--with
the 00Z ECMWF being slightly faster with Olivia versus the 06Z
GFS.  Both models show a fast progression of the storm--clearing
the islands by Thursday afternoon. The biggest hazards with Olivia
will be heavy rainfall, gusty winds and rough seas.  The 00Z ECMWF
bring more rainfall to the southern islands than the 06Z GFS--with
Maui receiving upwards of 10-15 inches with locally higher
amounts--especially along the terrain.  Some of these rains could
lead to flash flooding, particularly in Maui and the Big Island.

Once Olivia clears the region, surface high pressures builds in
from the north. Trade winds of 20 to 30 knots will be possible
especially on Friday and into the weekend--with winds coming back
down to 10 to 15 knots by the beginning of next week.  Dry
conditions are also expected to follow Olivia especially on Friday
and chances of daily showers will be possible over the weekend and
into next week. 


Reinhart