Issued: Sep 21, 2014 8:30 AM HST
Water vapor imagery shows an upper level trough extending across the central Pacific, from 26°N 140°W to 22°N 145°W to 15°N 170°W. A shortwave embedded within this trough is located just east of the Big Island, and is moving to the southeast at 15 mph. Isolated cumulonimbus clouds are located near and to the south of the trough, generally within 200 miles south of the trough between 150°W and 165°W. Cloud tops extend up to 45000 ft. Additional disorganized cumulonimbus clouds are located farther south of the trough, and are smaller and more isolated in nature. These cloud tops also extend up to 45000 ft.
Across the main Hawaiian islands, scattered to broken low clouds are located over the eastern half of Kauai. Broken low clouds cover the windward slopes of the Koolau range on Oahu, from Kaaawa southward. Overcast low clouds cover eastern Molokai east of pukoo, with scattered to broken low clouds extending from pukoo to kalaupapa. Scattered to broken low clouds are also located across eastern sections of Lanai and northeast sections of the west Maui mountains. Patches of broken to overcast low clouds cover portions of the lower slopes of Haleakala from huelo to Hana to Ulupalakua below 5000 ft.
On the Big Island, broken low clouds cover the windward slopes of the Kohala range. Broken to overcast low clouds extend 30 miles offshore to the northeast from Hamakua and north and south Hilo districts, and cover portions of the immediate coastal sections of those areas. These clouds cover much of Puna district, and also extend up to 30 miles offshore to the northeast and southeast. Patchy mid level clouds are located over Kau district. An area of broken to overcast low and mid level layered clouds is located just offshore to the south of Kau district, and extends over 150 miles south.
North of the area, a ragged cloud band associated with a dissipating surface front is located generally within 400 miles north of a line from 30°N 144°W to 20°N 180°. These clouds are composed primarily of showery open cell cumulus elements. Embedded towering cumulus elements extend up to 15000 ft. In the far western section, west of 178°W, isolated cumulonimbus clouds extend up to 35000 ft. The overall cloud band is nearly stationary. However individual elements are moving to the west and southwest at 15 mph west of 159°W, and to the east at 10 mph east of 159°W.