Issued: May 25, 2013 7:30 PM HST
Based on data through 7:00 pm May 25 2013 HST
A band of showery low clouds is moving over the Big Island of Hawaii and Maui county from the east while a band of high clouds is moving over the islands from the west.
As of 700 pm, clouds are isolated over Niihau with showery broken low clouds over Kauai and Oahu. The Big Island and the islands of Maui county are partly obscured by high, cirrus, clouds, CI. Beneath the CI, low clouds are isolated over Lanai and most of Molokai with scattered to broken low clouds over the east Molokai mountains. Showery, broken to overcast low clouds cover most areas of Maui and the Big Island. Low clouds are scattered over lower lee areas of west Maui and along the Kau and leeward Kohala coasts of the Big Island.
Low clouds near the main Hawaiian islands are moving from slightly north of east at 20 to 25 mph. The low clouds near the main Hawaiian islands are mainly showery cumulus clouds with tops around 11000 ft. A 110 mile wide band of showery broken to overcast low clouds lies south of a line from near Hana Maui to 20°N 150°W, 320 miles east of Hilo. This band has been shifting south slowly over the past several hours. Radars show isolated showers upstream of the islands from Kauai to Molokai and numerous showers upstream of Maui and the Big Island. There are scattered low clouds within about 250 miles upstream of the islands from Kauai to Molokai. There is a large area of broken low clouds east of 152°W.
The intertropical convergence zone, ITCZ, is unusually far north. Broken to overcast layered clouds associated with the ITCZ are south of a line from 12°N 140°W to 13°N 154°W, 357 miles south of the Big Island. There are scattered cumulonimbus clouds along the ITCZ south of a line from 11°N 140°W to 10°N 146°W.
Water vapor imagery, which shows features mainly above 24000 ft, shows a trough aloft centered from 27°N 140°W to a low aloft just east of the Big Island to another low aloft 780 miles west of Kauai near 21°N 172°W, to 18°N 180°W. A jet stream runs from 15°N 180°W to 18°N 170°W over the Alenuihaha channel to 20°N 150°W to 23°N 140°W. There is a band of broken to overcast CI south of the jet. The CI over the main Hawaiian islands is part of this band.