Issued: Apr 23, 2014 8:30 AM HST
Based on data through 8:00 am Apr 23 2014 HST
Water vapor imagery indicates weak upper level low pressure continues over the main Hawaiian islands with a trough extending to the west along 21°N. An upper level high pressure ridge resides east of the islands with an axis along 140°W. Scattered to broken cirrus clouds to the east of a curve from 10°N 159°W to 18°N 152°W to 25°N 161°W to 30°N 158°W are moving from the low into the ridge. These high level clouds are moving to the northeast between 20 and 40 miles per hour and rising to heights around 38000 feet.
At the mid to lower levels, scattered to broken stratocumulus clouds are spread across the area. These clouds are rising to heights between 9000 and 12000 feet and moving to the west around 15 miles per hour. There are two areas of the stratocumuli which are more dense. The first is within the area bounded by lisianski island to 27°N 167°W to gardner pinnacles to 22°N 175°W to lisianski island. The other area is north and east of the islands and partly obscured by the cirrus clouds. The rough boundary of these denser clouds is from 26°N 160°W to 26°N 140°W to 10°N 140°W to 26°N 160°W.
In the vicinity of the main Hawaiian islands at 1800 UTC, stratocumulus clouds are obscuring most windward slopes below 9000 feet with a few cirrus clouds moving across the sky. Over Niihau and Kahoolawe it is sunny. Over Kauai, Molokai, Lanai, Maui and the Big Island the windward slopes are mostly cloudy while the leeward sides are mostly sunny. Over Oahu, the windward slopes are mostly cloudy while the leeward areas are partly cloudy.