Issued: May 22, 2015 7:30 PM HST
An upper level low far NE of the main Hawaiian islands can be observed on water vapor satellite imagery with an associated trough axis extending from 30.0°N 151.9°W to 22.0°N 154.6°W. A sfc cold front boundary stretches from 30.0°N 148.6°W to 24.4°N 153.0°W to Kauai. Layered clouds and lines of stratocumulus clouds are pushing ENE ahead of the front covering the area between 23.0°N to 30.0°N and 141.0°W to 150.2°W. Cloud tops in these layered clouds are near 40 thousand feet.
Closer to the main Hawaiian islands, broken to overcast low clouds cover most of the Big Island below 8 thousand feet with a few showers lingering over the SE slopes of Mauna Loa, near South Point and over the windward coastline from Hawi to Waipio valley. On Maui county, broken low clouds prevail over most of Maui below 7 thousand feet, the S half of Lanai and most of Molokai. Lines of showers can be observed moving across Molokai from N to S. On Oahu and Kauai county, the combination of the afternoon convection and the aforementioned cold front boundary are keeping broken to locally overcast low clouds. Rain remains anchored over most of the Koolau mountains in Oahu, as well as areas over S Kauai from Koloa to Waimea.
Mainly broken cumulus and stratocumulus clouds cover the area N of the sfc cold front between 148°W to 170°W with cloud motion generally to the s/sw at about 15 mph. Coverage becomes mainly scattered elsewhere N of 10°N with cloud motion to the n/ne between 140°W to 150°W, and turning to the NW and W from 150°W to 180.
Far S of the islands, small clusters of thunderstorms lingered near the intertropical convergence zone between 05°N to 10°N and 150°W to 166°W with cloud tops ranging from 42 to 47 thousand feet.