Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
729 AM EST Mon Feb 25 2019

Valid 00Z Tue Feb 26 2019 - 00Z Tue Mar 05 2019

With the strong ridging stretching into Alaska, this will favor
lower heights to its south, roughly along 150W to the northeast of
Hawai'i next week. The tail end of another front will continue to
push south over the Hawai'ian islands--bringing slightly higher
precipitable water values with its progression. Meanwhile, expect
the Big Island to have precipitable water values over 1-1.2" due
to the lingering frontal boundary that passed across the island
chain on Sunday. This will result in higher chances of showers
especially for the northern half of the islands today as the front
pushes southward. As this system moves away, another closed
mid-level low quickly follows late Tuesday night/early Wednesday
morning. This low will drop southward toward Hawai'i and with it
another frontal boundary. With this system, higher precipitable
water values are expected especially from Moloka'i to the Big
Island.

By Thursday, high pressure will settle in with drier conditions.
Expect this quiet period to last through Saturday. The next system
to approach Hawai'i will begin to drop southward toward the
islands by late Saturday and into Sunday morning. There are some
differences in the ensemble means in terms of timing with this
system. By Monday morning, the 00Z CMC ensemble mean is farther
north and faster with the mid-level trough. The 00Z ECMWF ensemble
mean and 06Z GEFS mean show a closed low centered just to the west
of 150W. At the surface, the 00Z ECMWF ensemble mean has the low
just to the northeast of the 06Z GEFS mean and 00Z NAEFS mean. The
ECMWF ensemble mean is also slightly lower in pressure than this
low. Expect another round of showers to accompany this system.

Reinhart