Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
707 AM EST Thu Mar 08 2018

Valid 00Z Fri Mar 09 2018 - 00Z Fri Mar 16 2018

...Heavy rain possible next week...

Trades will be brisk for the next several days into next week as a
very strong 1050mb high approaches the Dateline tomorrow but
weakens as it moves past 170W next Monday to about 1030-1032mb.
Expect mainly light windward showers with some spillover to the
leeward side on NE to ENE winds as precipitable water values
slowly fall over the next couple of days to about 0.75-1.0" which
is about 1-1.5 standard deviations below average.

By the weekend, a trough will dig well to the northeast of Hawai'i
around 40N and move eastward as the upstream upper ridge axis
moves past 170W, which allows a weakness to its south to lift
northeastward, perhaps just west of the island chain. Most of the
models/ensembles reflect this at the surface by next Tue-Thu with
low pressure initially southwest of the region moving
northeastward near or over the islands. The 00Z Canadian is a
notable execption farther west but was away from the multi-center
ensemble consensus west of 160W in the North Pacific. Ensemble QPF
remains quite high for a 7-8 day lead time, suggesting the
potential for locally or even widespread moderate to heavy rain.
GEFS M-climate QPF was above the 99th percentile again in the
latest 00Z run, but uncertainty exists over the exact placement.


Fracasso