Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 725 AM EST Fri Nov 16 2018 Valid 00Z Sat Nov 17 2018 - 00Z Sat Nov 24 2018 An upper level trough passing to the northeast of the Hawaiian Islands will drag a moist and unstable airmass across the region this weekend. This will increase rain shower activity, especially for windward locations, with thunderstorms and locally heavy rainfall possible. Throughout the next week though, surface high pressure building to the north and west of the state will also keep easterly trade winds gusty with light windward showers possible. Models and ensembles indicate another cold front/upper level trough may approach the islands from the west towards the end of next week resulting in another round of increased precipitable water values and precipitation chances. Santorelli