High pressure far northeast will drive trade winds tonight. Wind speeds will taper off through much of this week as remnants of Tropical Cyclone Genevieve linger between the high and Hawaii. Clouds and showers will favor windward and mauka areas, with some enhancement possible for the western half Tuesday through Thursday due to an upper trough setting up to the west.
A 1032 mb surface high centered far northeast of Hawaii will drive breezy trade winds tonight. Winds will carry in scattered low clouds and showers focusing across windward slopes. Wind speeds will decline to gentle to moderate through much of the week as remnants of former Tropical Cyclone Genevieve linger between Hawaii and the high pressure system. It is not expected to impact Hawaii aside from the decrease in wind speeds.
Model guidance continue to show an upper level trough near the western end of the state Tuesday through Thursday, which may provide some enhancement of incoming trade wind clouds and showers over the western half of the state. This feature will move north away from the area on Friday. Models are hinting at some incoming tropical moisture along a trough connected to the ITCZ. Trades will push this area of moisture across Big Island and Maui.
Generally VFR with slowly weakening but still breezy trade winds. Occasional MVFR ceilings and visibilities in isolated stronger showers mainly over windward and upslope mauka exposures. No AIRMETs currently in effect and none expected.
A ridge of high pressure north of the state will weaken tonight as a front passes far north of the state. This will allow the trade winds to steadily weaken through Tuesday. Winds should decrease below Small Craft Advisory thresholds by Monday. The current SCA is for the windier waters around Maui County and the Big Island through tonight. Trade winds should restrengthen by the end of the week as a strong high rebuilds far northeast of the state.
Surf along south facing shores will stay below seasonal averages with mainly background energy throughout most of this week. The next small, long period south swell will arrive by Saturday with a slight bump in south shore surf heights through next weekend. A series of south swells are expected the following week (week of Aug 9th), which should produce surf heights at or above seasonal averages.
East facing shores will remain rough and choppy through tonight, but should see a steady decrease as the trade winds weaken into Monday. Small, medium period easterly swell generated from former TC Genevieve will linger over the next few days.
Surf along north facing and west shores will remain flat to tiny through the forecast period except for areas exposed to the easterly trade wrap.
Small Craft Advisory until 6 AM HST Monday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters.
