Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
715 AM EST Wed Jan 18 2017

Valid 00Z Thu Jan 19 2017 - 00Z Thu Jan 26 2017

An impressive upper ridge of high pressure overhead will be in
control through this Friday, basically keeping the state mostly
dry and trades down for the most part. Global models and ensembles
are in complete agreement with this well advertised closed dome of
high pressure and 594dm closed contour. However, this weekend a
phasing upper trough over the pacific will amplify and drive a
strong frontal zone toward the state. The guidance show this
well-defined digging upper trough and strong cold front, which
appears to pass through the entire chain of islands. The spread
with the global models has narrowed some and still indicate the
front could stall the front near the Big Island early next week.
Expect some showers associated with the front over the weekend and
then perhaps enhanced windward showers/rain especially for the Big
Islands and northeastern edge of Maui/Molokai and Oahu. By next
Wednesday, another upper ridge will begin to build in from west to
east, the weakness overhead will advance downstream and more
traditional easterly trades will commence.

Musher