Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
818 AM EDT Tue Aug 28 2018

Valid 00Z Wed Aug 29 2018 - 00Z Wed Sep 05 2018

The moisture plume to the east of Tropical Depression Lane will
likely result in continued showers and areas of locally heavy
rainfall across Hawaii into tonight, but the model consensus is
that Hawaii should gradually begin to dry out over the next couple
days as the moisture plume gradually shifts westward away from the
islands, and a drier air mass overspreads the region from the
north. Models/ensembles show broad agreement that a large and
expansive upper ridge initially centered over the Pacific Ocean
well north of Hawaii will begin to quickly break down late this
week through the weekend, allowing an upper level low to drift
westward in the general direction of Hawaii. While low-level
easterlies of 20-25 kt will persist into late week, the
approaching upper low will disrupt the trades by this weekend,
with generally light and variable winds expected. A gradual
increase in moisture and convective instability will accompany the
upper low, thus would expect am gradual increase in shower
activity by the weekend into early next week, which may affect
areas beyond the typical windward locations due to the lack of
trades in the vicinity of the low. By the middle of next week the
upper low may weaken as some of the energy gets absorbed into an
amplifying upper trough over the north central Pacific, bringing a
gradual resumption of the trades to Hawaii.

The latest model guidance consensus along with the official
forecast track from the National Hurricane Center is for Hurricane
Miriam to remain well east of the Hawaiian Islands as it turns
northward near 140W later this week.

Ryan