Moderate trades weaken giving way to land and sea breezes through early this week. Increasing moisture will move up the island chain from the southeast through the early portion of the week resulting in increased shower coverage over island interiors. Trades return late Wednesday and continue through the forecast period.
Latest satellite and radar imagery show a short-wave thats near overhead or just to the northeast of the island chain and sagging southward. Low clouds are moving across the islands within the trade wind flow. Radar imagery shows scattered showers ongoing across the islands, mostly impacting windward and mauka locations with some limited spillover to leeward areas. Some heavier showers are impacting windward Big Island causing some minor flooding or ponding on roadways and low-lying flood prone areas.
As the aforementioned shortwave continues advancing through the area, increasing showers will be most pronounced over the eastern end of the state today then expand up the island chain by Tuesday. Trades back northeast and strengthen to moderate levels during the early portion of the week, focusing showers windward and mauka. Breezy trades then establish during the second half of the week as the subtropical ridge strengthens north of the area.
An upstream trough will continue to bring periods of MVFR low clouds and showers to windward mountain areas of most islands through the early morning hours. Pulses of wet weather continue across the Hawaii region for the next few days.
AIRMET Sierra remains in effect for mountain obscuration above 2000 feet for most windward island mountains through the early morning hours.
Light to moderate trade winds will persist today, then gradually strengthen into the fresh to locally strong category Tuesday through the latter half of the week as the subtropical ridge builds north of the state. Small Craft Advisory conditions will likely develop in the typically windier channels and waters around Maui County and the Big Island beginning Tuesday.
Surf along exposed south-facing shores will remain elevated this week as a series of overlapping south to south-southwest swells move through the region. The current south swell, which peaked over the weekend, is slowly easing, with the peak energy down into the 14-15 second band. Long-period forerunners from the new south-southwest swell will steadily fill in today, leading to a building trend by tonight.
Surf is expected to return to advisory levels tonight through Tuesday and likely rise above the advisory threshold by midweek as the swell peaks. While some of the peak energy may have missed the PacIOOS American Samoa buoy to the east over the weekend, observations suggest surf heights should peak locally near, or possibly just below, the High Surf Warning threshold of 15-foot faces along south-facing shores around Wednesday. A gradual downward trend is then expected through the latter half of the week.
Surf along north-facing shores will increase Tuesday and remain up through Friday as a pair of overlapping northerly swells arrive from a broad gale far north of the state near the Aleutian Islands. Seasonal surf conditions should return by the weekend.
Surf along east-facing shores will gradually build by midweek as strengthening trade winds generate increasing short-period wind waves. Surf should return to near seasonal levels by the end of the week.
None.
