Issued: Jul 28, 2016 2:30 PM HST
Based on data through 2:00 pm Jul 28 2016 HST
Visible satellite imagery shows a large field of stable stratocumulus /sc/ clouds moving over the main Hawaiian islands from the east, carried westward by a sturdy trade wind flow. As is typical for this type of shallow cloud type, cloud cover over water has decreased since this morning in response to diurnal warming of the cloud tops. Meanwhile, over the islands, cloud cover has also decreased in most areas since this morning, and mostly sunny and dry conditions prevail around the state this afternoon. Low clouds near the islands continue to move toward the west at speeds between 20 and 25 mph, except through the Alenuihaha channel, where low cloud motions are accelerated to near 30 mph.
A close-up look of the islands reveals mostly sunny skies over Kauai and Niihau and adjacent waters, although few to scattered low clouds are over interior portions of Kauai. The wave clouds observed over Oahu and near shore leeward waters this morning have since dissipated, and most coastal areas on the island are under mostly sunny skies. A few low clouds are over near shore waters of the north shore, with scattered to broken low clouds over and just west of the Koolau range. Cloud cover on Molokai has decreased since this morning, with sunny skies prevailing island wide, aside from small sc and cumulus /cu/ over the northeast slopes. A similar pattern has developed on the other islands of Maui county, with nearly cloud-free skies noted over Lanai, Kahoolawe and Maui. The exceptions on Maui include scattered to locally broken low clouds that are banked up along the lower windward slopes of the windward west Maui mountains and along windward Haleakala.
Water vapor imagery shows that an area of light winds aloft is over the islands, with ridges aloft located northeast and southwest of the islands, and troughs located northwest and southeast of the islands. The trough to the east and southeast features a westward-moving closed low aloft centered near 23°N 145°W, or about 850 miles east of Oahu. This low aloft has a weak surface reflection, with a poorly-defined low-level surface trough along 144°W from about 20°N to 26°N.
Scattered moderate thunderstorms are located over the northwestern portion of the Papahanaumokuakea marine national monument, just southeast of Midway atoll. These thunderstorms are developing in response to a weak, northeast to southwest oriented, surface trough which contains the remnants of post- tropical cyclone Darby as it interacts with a weak trough aloft.