Last Updated on Monday, 22 September 2014 07:35
Winds Statewide in a glance ...go HERE (this link is also the 4th drop down under weather)
Sep 22, 2014 3:30 AM HST
The prevailing light winds will finally shift to a more typical trade wind pattern starting today, bringing some relief from the humid and muggy conditions of the last several days. As the trades establish, showers will become more focused over windward and mountain areas. A wetter trade wind pattern is expected for the second half of the week.
A tropical disturbance a couple hundred miles WSW of Kona is still keeping enhanced low level moisture around the Big Island and adjacent S and W coastal waters. Meanwhile, latest water vapor satellite data shows an upper level trough aligned from SW to NE near the Alenuihaha channel and Maui. These features are still providing favorable atmospheric conditions for passing showers to move across the Big Island, mainly over windward areas and the SE slopes of Mauna Loa, through the late morning hours.
The prevailing light wind regime will finally begin to modify as a stationary sfc frontal boundary about 400 miles N of Kauai is replaced by a building high pressure system NW of the aloha state. Pressure gradients will increase across the area with a return to a more typical trade wind flow during the first half of the week. As the trades build up, expect a gradual relief from the muggy and humid conditions of the last several days. The trades will also shift the focus of shower activity back to windward and mountain areas.
Latest global model solutions show a frontal boundary approaching the area from the N, reaching the main Hawaiian islands late Wed and into Thu. This front will also drag a band of enhanced moisture with it, bringing a rather wet trade pattern during the second half of the week. The overall timing and duration of this scenario is still being evaluated, but if the models are correct this band of moisture could linger across the islands through at least Sat. Thus, there is a possibility for extended periods of very wet conditions especially over windward and mountain areas to last through the weekend. The latest forecast package has been updated to carry increasing pops/rain activity from Thu through Sat.
Surf heights are expected to remain near background levels through most of the week. A slightly higher swell is expected from the NNE Thursday through Saturday. A moderate SSW is due next weekend.