Issued: Dec 08, 2013 7:30 PM HST
Based on data through 7:00 pm Dec 08 2013 HST
A nearly stationary upper trough remains near the Big Island with a trough axis stretched from a relatively weak upper low near 29°N 140°W across the Big Island to 13°N 158°W. Widely separated, isolated thunderstorms can be observed along the trough. A second upper level trough moving E at around 30 mph is between Kauai and Oahu with an axis extending from 28°N 156°W to 19°N 159°W.
The influence of those two upper troughs is keeping a rather unstable airmass across the islands. Further to the NW of the island chain, a front stretched SW from 30°N 165°W through 27°N 170°W. A fairly narrow, 50 to 60 mile wide associated cloud band ahead of the front is moving ESE at 15 to 20 miles an hour. The band consists of bkn to ovc low clouds with a few thunderstorms along it. A low pressure system associated with the front was centered near 34°N 164°W and is moving toward the NE.
At 7 pm HST, Kauai remains cloudy to mostly cloudy with bkn to ovc low clouds and passing bands of showers from the S. The Big Island remains nearly completely covered by bkn low and mid lvl clouds with lingering showers over the leeward coastline near Kailua-Kona, the N Kohala district and portions of the windward coastline from Hilo to Waipio valley. On Maui county, S and leeward Haleakala are mostly bkn under low clouds and with passing showers moving in from the S. On Oahu, the prevailing sct low clouds are being replaced by incoming clusters of bkn to ovc low/mid lvl clouds and showers approaching from the S, which should impact the leeward side of Oahu and the Waianae range during the rest of the evening hours.
S of the islands, a cluster of active thunderstorms can be observed centered around 14.5°N 153.7°W, or about 360 miles SE of the Big Island.