Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 819 AM EDT Thu Sep 14 2017 Valid 00Z Fri Sep 15 2017 - 00Z Fri Sep 22 2017 A stationary frontal boundary currently situated north and northwest of Hawai'i is expected to gradually lift northwestward and wash out over the next few days as an upper-level weakness in the subtropical ridge drifts southwestward and westward. Trades are expected to remain relatively weak or even non-existent until later Friday as a closed upper high builds eastward along 35N. This will result in increasing easterly low-level flow this weekend into early next week as the pressure gradient increases over the area (1031mb sfc high near 40N). The ensembles show drier air filtering into the region from the east in between deep tropical moisture along the ITCZ and higher precipitable water values around the upper high near 27N. This would support generally isolated windward and mauka showers. Fracasso