Issued: Dec 17, 2014 8:30 AM HST
Water vapor imagery showed an upper low lingering near 15°N 175°W this morning. The low had weakened and was somewhat less discernible than 24 hours ago. The low was nearly stationary. Fragment of broken cirrus clouds generated by this upper low were drifting eastward and mostly contained in the area from 17°N to 23°N between 172°W and 163°W. A few small tufts of cirrus were making it further east and traversing the Hawaiian islands at times.
Water vapor imagery also showed an upper level ridge of high pressure lying from east to west and extending over the state. The ridge axis stretched from near 20°N 130°W to near 21°N 160°W.
A fairly weak front to the northwest stretched through 30°N 162°W to 27°N 170°W then continued west to near 28°N 180°E. The front strengthened as it continued northeastward toward the gulf of Alaska. But the tail end of the front south of 30°N was comprised of mostly broken low clouds. The front was moving east near 40 miles an hour along 30°N latitude, but was stationary west of 170°W longitude and even drifting a bit northward near the dateline.
Meanwhile, somewhat weakened trade winds were still sweeping a steady supply of low clouds into the islands from the east. These low clouds were moving along at just over 20 miles an hour. Between 18°N and 23°N from 140°W to 170°W, scattered to broken cumulus and some stratocumulus clouds were common. The clouds were separated by ample amounts of clear sky. From 23°N to beyond 30°N between 140°W and 155°W, broken to overcast stratocumulus clouds were the rule.
At 8 am, almost all of Kauai was cloudy due to a mix of low and high clouds aloft. Most of Oahu was cloudy except for sunny skies over the leeward sections. Some low clouds were hugging the east sides of Molokai, Maui and the Big Island. But the majority of these islands as well and nearly all of Lanai was sunny to mostly sunny. Cloud tops near the islands were mostly in the 9000 to 12000 feet range.