Moderate to locally breezy trade winds will persist today as high pressure remains north of the state, with weaker trades Tuesday through at least Friday. Windward and mauka showers will continue, with a slight uptick in moisture likely Tuesday into Tuesday night, and possibly from Friday into next weekend.
Radar showed numerous showers across the islands today, mainly windward and mauka, but not leaving the lee side out completely. Rainfall amounts in the past 6 hours ranged up to a half inch on windward and mauka areas on most islands, and up to three-quarters of an inch on the Big Island. Skies were partly to mostly cloudy in most areas. Winds were a little stronger than Saturday, averaging 12 to 25 mph, with gusts over 40 mph in the windier locations.
As a strong surface high pressure system remains nearly stationary to our north, we will be kept in east to northeast trade winds through the coming week. Winds will weaken slightly Monday, and then a little more Tuesday, then remain around that level for several days. An area of increased moisture, and therefore showers, is still on schedule to arrive Tuesday through Tuesday night, with drier air moving in for Wednesday and Thursday. Details remain to be worked out beyond Thursday, but there are indications of additional moisture moving back in Friday and potentially lasting into next Sunday.
Breezy trade winds will continue, bringing intermittent shower activity across the islands through the period. Intermittent MVFR is possible under showers, otherwise VFR is generally expected.
AIRMET Sierra is in effect for windward Kauai and Oahu. This is expected to remain in effect through the early morning, and may scale back as models suggest a downtrend in shower activity later in the day.
AIRMET Tango also remains in effect for low-level turbulence downwind of terrain, and is expected to continue for the next several days as we remain under a breezy trade wind pattern.
The trades will gradually ease today through Tuesday as the high pressure north of the islands lifts northeast and weakens. A Small Craft Advisory (SCA) is now in effect for most waters through 6 PM Monday, and for a smaller subset of the typically more windy waters through 6 AM Tuesday. The SCA will likely not be needed for any waters Tuesday as winds should have decreased to below headline thresholds. These lighter trades should continue through Wednesday night, then may increase a bit Thursday and Friday as high pressure northeast of the islands drops a bit further south and tightens up the local pressure gradient.
The current small, long-period southwest swell will peak today, then gradually decline through the middle of the week. A series of overlapping small south and southwest swells will then give a small boost to the surf along south facing shores Thursday through next weekend, with perhaps a more sizable south swell moving in early next week.
Surf along east-facing shores will remain rough and choppy today, then steadily decline through the middle of the week. Surf will then hold steady at slightly below normal levels along east facing shores late in the week through the weekend.
A series of small, long to medium period west to west-northwest swells generated by former Super Typhoon Bavi will be possible throughout the week. Otherwise, no significant north or northwest swells are expected, so surf along north-facing shores is expected to remain flat to tiny.
Peak monthly high tides combined with water levels that are running slightly higher than predicted will lead to minor flooding along the shoreline and in low-lying coastal areas. Coastal flooding is possible around the daily peak tide, which will be during the afternoon hours. A Coastal Flood Statement remains in effect through Tuesday afternoon.
Small Craft Advisory until 6 AM HST Tuesday for Kauai Northwest Waters-Kauai Leeward Waters-Maalaea Bay-Pailolo Channel- Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters.
Small Craft Advisory until 6 PM HST this evening for Kaiwi Channel-Maui County Windward Waters-Maui County Leeward Waters.
