Surface observations around the main Hawaiian islands still reported light to moderate trade winds, and speeds remained higher where the flow accelerated around headlands and between islands. Precipitation was quite sparse overnight, but the air mass moistened slightly, and the inversion above it rose considerably over the southeast end of the state. Shreds of cirrus followed a jet stream out of the ITCZ, passing over the state at times. Broad but shallow troughing prevailed aloft to the north of the state, while a mid-level ridge grew toward the islands slowly from the east.
Guidance more solidly agreed in predicting the active ITCZ to spout a deep plume of enhanced moisture over several islands from late today into Saturday. The mass of stratus layers visible on satellite images to the southeast of the Big Island possibly represented the leading edge of this plume. As this feature moves northwest, shower activity will increase over the Big Island, and then Maui county. While it may not reach Oahu or Kauai at all, more likely these islands will receive some of the clouds and showers by Saturday, though to a much lesser degree than Maui or Hawaii counties. Guidance also predicted the mid-level ridge to expand over the state from the east during this time, so subsidence will limit cloud development to some degree, though probably not enough to counteract completely the influence of plentiful water vapor.
The subtropical ridge should keep the trade winds blowing through the forecast period, and may support slightly increased speeds from Friday into Saturday as well. By late in the weekend, solutions started to trend toward climatology again. Wind speeds should diminish slightly, while the moist air mass departs toward the west, and drier air advects in from the northeast.