Issued: Dec 12, 2013 2:30 AM HST
Based on data through 2:00 am Dec 12 2013 HST
Around the main Hawaiian islands, scattered low clouds prevail across the island chain, except for narrow bands of bkn low clouds with rather dispersed showers moving into windward portions of the Big Island from the E. Some locally bkn low clouds also linger over the SE slopes of Mauna Loa. Small passing showers can also be observed moving across windward Maui, and E and central Molokai. On Oahu, bkn low clouds linger over the central portions of the Koolau mountains. A couple of narrow bands with embedded disperse showers can be observed on satellite and radar data approaching windward Oahu from the E. A few showers can be observed still lingering over S Kauai from Waimea to Koloa.
A robust trade wind regime dominates most of the area. E of 160°W, scattered to locally bkn cumulus and stratocumulus clouds prevail with individual cloud elements moving W or WNW at 15 to 20 mph. An upper lvl trough extends into the N portions of the area with a base located around 29.0°N 163.1°W, or about 520 miles NW of Kauai. Associated high and layered clouds cover much of the area between 20°N to 30°N and 160°W to 180.
A surface frontal boundary associated with the aforementioned trough extends SW from 30.0°N 163.0°W to 20.0°N 171.8°W. A swath of layered clouds and embedded thunderstorms extends along and ahead of the front with an average width of 180 miles. A cluster of active thunderstorms within this swath is centered around 28.7°N 162.8°W, or about 480 miles NW of Kauai, with cloud tops reaching 44 thousand feet. The upper trough is departing to the NNE at around 25 mph while the surface front is slowing down while migrating E at 10 to 15 mph.
Far S of the islands, bkn layered clouds can be observed near the inter tropical convergence zone, or ITCZ, covering much of the area between 03°N to 12°N and 160°W to 180 with highest cloud tops reaching 45 thousand feet.