HONOLULU (KHON2) - After a breezy several days, trade winds are on a steady decline this afternoon while the atmosphere is gradually destabilizing. Trades are dropping as surface high pressure to the northeast is pushed away from the region and the local pressure gradient relaxes due to surface low pressure developing along a front about 1,000 miles northwest of Kauai. A weak low aloft is already parked over the islands, and as the upper-level trough generating the surface low approaches, the atmosphere is gradually destabilizing. This has not resulted in any significant increase in shower activity today. However, a shallow band of moisture just east of Maui and the Big Island should bring some boost in shower coverage for windward areas on those islands before sundown, and a few showers could flare up across leeward Big Island into the evening. Chances for showers, some heavy, increase tonight into Sunday as trade winds decrease further and shift out of the east to southeast. The low to the northwest of Kauai will strengthen as the high to the northeast of Hawaii weakens, causing the decline and shift in the winds, and a broad upper-level trough will stretch across the region, creating some instability. Meanwhile, a mid-level trough, currently just south of the Big Island, will drift over the state. ...read more read less