As Honolulu basks in the typically dry trade wind conditions of summer, the National Weather Service in Honolulu forecasts this trend to continue through early tomorrow, with emphasis on windward and mauka showers occurring mostly during early mornings and overnights. According to their latest weather update, high pressure systems located to the northwest and northeast of Hawaii are responsible for driving the current breezy easterly winds.
The report states that "stable conditions will stay in play as a result of ridging anchored north of the state," which indicates that the winds, along with showers focused on higher elevations, are expected to persist, The lower inversion near 5,000 feet creates a shallow boundary layer, revealed by the morning's stratocumulus clouds and minimal radar activity, while dry mid to upper level air has so far reduced rain chances across the islands. However, an upper level disturbance is forecast to develop northeast of Hawaii by tomorrow, and this is anticipated to gradually weaken the trades and possibly enhance island-wide showers as the week progresses.
Aviation alerts by the NWS include an AIRMET Sierra, currently in effect for N through SE sections of the island chain due to mountain obscuration, and an AIRMET Tango for moderate low-level turbulence lee of the terrain. Meanwhile, "breezy to locally windy trades will continue over the next few days," and though brief MVFR conditions are possible in showers, VFR conditions should predominantly prevail.
Marine activities are also impacted, with a Small Craft Advisory (SCA) in place for all Hawaiian Coastal Waters, expected to remain until tomorrow, due to the strong high-pressure ridge that persists north of the islands, the advisory will decrease in coverage after 6 AM HST, remaining for the windier near Maui County and the Big Island. Additionally, a High Surf Advisory is in effect for south-facing shores of all islands until 6 PM HST Monday, with surf along east facing shores also rough and choppy expected to improve around midweek, as trades ease according to the NWS update.
The Honolulu Forecast Office also notes that although the exact increase in shower activity to offer relief from the recent dry weather has yet to be confirmed, an increase in showers is most likely later in the week, especially over the Big Island and Maui Counties where the elements for rainfall are best aligned.
