Issued: Jul 24, 2014 2:30 AM HST
Water vapor images showed an area of low pressure in the middle atmosphere near 30°N just east of the dateline. Towering cumuli and their thin high layered debris clouds formed under this feature within 350 miles of the point 28°N 173°W. Towering cumuli and their thin high layered debris clouds forming within 90 miles of the points 21°N 172°W, 19°N 179°W, and 16°N 169°W also may have been associated with the low.
Otherwise, cloud cover across Hawaiian waters consisted mainly of marine stratocumuli and cumuli. These clouds were greatest in areal coverage east of the curve from 30°N 147°W to 27°N 146°W to 21°N 153°W to 25°N 162°W to 21°N 165°W to 16°N 164°W to 19°N 149°W to 15°N 140°W. Individual small cumuli also occurred throughout. These clouds increased in areal coverage with time during the past six hours. They generally moved toward the west southwest at 15 to 20 miles an hour, and rose to heights of 8000 to 10000 feet, though taller cumuli approached 13000 feet.
To the south, light to moderate thunderstorm activity continued in the ITCZ from 13°N to 02°N, chiefly east of 154°W. Layered middle to high debris clouds from this and earlier convection mostly to partly obscured lower features from 16°N to the equator.
A trough of low pressure located in the ITCZ about 1100 miles southeast of the Big Island of Hawaii produced thunderstorms showing a limited, asymmetrical organization. This system may develop during the next few days as it moves further westward across the central Pacific.
Across the main Hawaiian islands, cloud cover consisted mostly of marine stratocumuli and cumuli moving ashore along slopes facing north through east, especially from Oahu to the Big Island. Layered debris clouds from afternoon cumulus buildups on Wednesday had diminished during the past six hours, but still lingered in places, especially along lower to middle west slopes of the Big Island. These clouds varied in height from 7000 to 9000 feet. Radar data from near the islands showed scattered showers over northeast Oahu, northeast through southeast slopes of Haleakala on Maui, over northeast slopes of north Kohala district on the Big Island, and offshore to the southeast of the Big Island, but isolated showers at most elsewhere.