Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
226 AM EST Sun Dec 15 2019

Valid 00Z Mon Dec 16 2019 - 00Z Mon Dec 23 2019

Upper ridging will build into the area Monday as a cold front dips
southward toward the region around Tuesday. Trades will weaken a
bit on Sunday only to increase in advance of the front Monday.
Generally light windward/mauka showers are likely. Trades will
slowly then decrease through Thursday. By next Fri/Sat, another
front may approach the region and perhaps sink through the
islands, enhancing some windward showers. Surface high pressure
behind it may be quite strong per some models and even the ECMWF
ensemble mean showed PMSL above 1032mb which is above the 99th
percentile for the third week of December. Trades may become quite
breezy with the strong pressure gradient, with additional showers
both windward and leeward on strong easterly to ENE flow. By late
Sat into Sun, GFS remains bullish on developing and tracking low
pressure off the ITCZ near 180 farther east than most of the other
models and ensembles, but still keeps the plume of heavier rain
west of Kauai through 00Z/23.

Fracasso