StormWatch Lite · Oʻahu

Radar shows scattered windward and mauka showers across the state this morning. A large surface high continues to strengthen to our north. Aloft, a weak upper level low to our east will become a trough that stretches from southern CA all the way out to us. The trough will be weak, and apart from a slight increase in instability, we won't see much from it. Several impulses of increased moisture will move toward and over the state, especially the eastern end, over the coming week. The first will move through this afternoon and evening, and reach all islands. The second should move over the area late Sunday through late Monday, boosting showers mainly across the eastern end of the state. Finally, another area may reach us next Thursday, but at this time range confidence is low. Models currently indicate the focus of this one would be on the eastern end. Trade winds will remain moderate to breezy through the coming week, with the a slight increase possible Tuesday evening. A slight weakening may develop next Thursday, but as mentioned in the previous paragraph, at seven days out, confidence in that level of detail is low. Finally, guidence indicates that the upper level trough extending from southern CA over to us may join with energy moving in from the northwest and strengthen toward the middle of next week. It is unclear at this time whether it will develop into a closed low or a stronger trough. Either way, it may draw tropical moisture northward toward the state and present a heavy rain threat. Details should become clearer in a few days.