A strong high pressure system north of the Hawaiian Islands is gradually weakening. Trade wind speed trends will decrease to the moderate to breezy range tonight into Sunday, and then to moderate levels from Monday onward and the high continues to weaken. Strong and stable subsidence aloft will limit shower potential for most days into next week. However, a slight increase in cloud and shower trends may develop later tonight through Saturday as a weak easterly wave moves from east to west down the island chain.
The pressure gradient over the state has weakened and trade wind speeds are on a decreasing trend. Scattered clouds with isolated showers embedded in the trade wind flow will focus along windward and mauka regions. Models continue to show a subtle low level trough moving from east to west across the island chain tonight through Saturday. This could elevate inversion heights enough allowing for increasing shower trends, mainly over windward and mountain areas with some spillage to leeward areas of the smaller islands. However, total precipitable water values locally and upstream will remain near to below average so this may put an upper limit on rainfall totals.
The high far north of the state will continue to gradually weaken into next week resulting in a decreasing wind speed trend. Trades are expected to become moderate to breezy Saturday to Sunday, before further weakening to more moderate levels Monday onward. Some of the more wind favored areas may see brief periods of locally breezy wind speeds next week. Can expect stable and mostly dry weather trade wind weather through the rest of the forecast period. Strong and stable subsidence under an upper level ridge will continue to limit vertical cloud heights and shower development into much of next week as well as near to below average precipitable water values.
Breezy to locally windy trade winds will remain through tonight and slowly decrease in strength starting tomorrow. Clouds and showers will focus primarily over windward and mountain areas with enhanced showers during the overnight hours. MVFR ceilings and visibility can be expected in any showers. Overall VFR conditions will likely prevail.
AIRMET Tango remains in effect for moderate low-level turbulence for areas downwind of island terrain and will likely be needed through tomorrow.
Strong surface high pressure far northeast of the state will maintain locally breezy trades through this weekend. The Small Craft Advisory has been scaled back to just the typical windier areas around Maui County and the Big Island through Saturday evening. By early next week, the aforementioned high is forecast to move further west and allow trades to ease into the gentle to fresh range.
Near shore buoys continue to indicate a small, medium to long period south swell, which will provide small surf for south facing shores through Saturday. By mid to late next week, another small long period, south southwest swell should bring a slight bump up in surf along the south facing shores.
The enhanced trades will continue to produce rough and choppy surf for the east-facing shores through this weekend. Local wind swell may wrap into select north and south facing shores. Surf along north facing shores will remain nearly flat, typical of this time of year.
Small Craft Advisory until 6 PM HST Saturday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters.
