Breezy trades weaken slightly during midweek then restrengthen by late in the week. Potential tropical development threatens to bring heavy rainfall to eastern portions of the state during the latter half of the week, though uncertainty remains higher than usual at this time.
Issued at 312 PM HST Sun Sep 20 2026 Breezy trades will continue into Monday. Isolated showers and brief MVFR conditions are possible mainly over windward and mountain areas. Shower activity may increase by Monday night, especially over windward areas of Big Island.
AIRMET Tango remains in effect for moderate low-level turbulence downwind of island terrain due to the breezy trades.
Issued at 312 PM HST Sun Sep 20 2026 The gradient between weak high pressure north of the islands and pressure falls south of the islands will maintain fresh to locally strong trade winds across the region through at least Monday night. Therefore, the Small Craft Advisory has been extended through Monday night for the typical windy channels and waters of Maui County and the Big Island. After a slight reduction in trade wind speeds heading into mid week, they will restrengthen during the latter half of the week as a trough or potential weak tropical disturbance moves south of the islands. Shower coverage will also increase, along with the potential for isolated thunderstorms, particularly across the eastern waters.
Surf along south facing shores will remain above average over the next couple of days as a long period SSW swell holds relatively steady. This swell will then gradually fade heading into mid week. A slightly smaller, long-period south-southwesterly swell will fill in late this week into next weekend generated by a series of lows near New Zealand. West facing shores will experience a bit of the southerly wrap through most of the week.
Breezy trade winds will maintain moderate surf along east facing shores for the next several days. Surf along north facing shores will remain flat to tiny through Monday, but will see a slight bump Tuesday into Wednesday as a small, medium-period northwest swell fills in from an Aleutian low. Then a small, long-period west-northwest swell expected to be generated by Tropical Storm Dujuan as it curves northeast near Japan and potentially strengthens into a hurricane will build locally Friday into next weekend, increasing surf along north and west facing shores.
Small Craft Advisory until 6 AM HST Tuesday for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters- Maalaea Bay-Pailolo Channel.
