Surface high pressure strengthens to the northeast of the state today and will bring an increase in trade wind flow. In addition, expect an uptick in low cloud cover and shower activity through early Monday over windward portions of Maui, Molokai, and Oahu as an area of enhanced moisture moves in from the east. From late Monday through Friday, light easterly winds will return to the region. Afternoon coastal sea breezes should help to focus scattered clouds and isolated showers over mainly interior and mountainous locations. For the latter part of the week, deeper moisture moving in from the southeast could bring increased precipitation chances to the Big Island.
Moderate and stable trades are expected for the period. Low-level moisture embedded within the trades may make for light showers and localized MVFR conditions at times, mainly for Maui County and Oahu, otherwise VFR conditions are expected.
AIRMET Sierra is in effect for mountain obscuration across windward Oahu and Maui County due to the aforementioned light shower activity. This is expected to improve later today, however.
A sharp, though weak, upper level trough is producing moderate turbulence aloft over the Big Island, where AIRMET Tango is in place above FL300.
A large long-period south-southwest (200 degree) swell will continue to fill in today and peak tonight into Monday before gradually declining through the rest of the week. Latest buoy readings continue to show a gradual upward trend with buoy 51002 showing swell heights of around 4 to 6 feet at 19 to 20 seconds. The large south-southwest swell combined with King Tides will create the potential for significant wave run up along south and west facing shores this afternoon and Monday afternoon. Due to the potential for significant wave up, the High Surf Advisory was upgraded to a High Surf Warning for areas exposed to the south- southwest swell.
Very little swell energy is arriving along north facing shores, keeping surf tiny to flat. A small bump in surf is possible for north- facing shores on Tuesday with the arrival of a small northwest swell and a smaller north swell. Gentle to moderate east-northeasterly winds expected through next week will keep surf along east facing shores below seasonal average.
A Coastal Flood Statement remains in effect for minor coastal flooding of vulnerable low-lying coastal roadways, docks, boat ramps and other coastal infrastructure. King Tides combined with water levels that are running higher than predicted will lead to minor flooding potential around the daily peak tide, which will be during the late afternoon and early evening hours, through at least Tuesday. While minor coastal flooding is expected along all shorelines, the combination of the south-southwest swell, King Tides and the daily high tide will make low-lying coastal areas along south and west shores susceptible to more widespread coastal flooding through the first half of next week.
High Surf Warning until 6 AM HST Tuesday for Big Island South- Big Island Southeast-East Honolulu-Ewa Plain-Honolulu Metro- Kahoolawe-Kauai South-Kauai Southwest-Kipahulu-Kohala-Kona-Lanai Leeward-Lanai South-Maui Central Valley South-Maui Leeward West- Molokai Leeward South-Molokai Southeast-Niihau-South Haleakala- South Maui/Upcountry-Waianae Coast.
