textproduct: Honolulu

SYNOPSIS

Breezy easterly trade winds will persist through tonight, then ease into the light to moderate range from Thursday through Saturday. Clouds and showers will favor windward and mauka areas, with a period of increased shower activity through early Thursday as a band of moisture moves through the islands. A few afternoon clouds and showers may develop over interior and leeward areas Thursday through Saturday where localized sea breezes form. Trade winds are expected to strengthen again late this weekend and into early next week.

DISCUSSION

A pocket of moisture embedded in the trade wind flow will continue to move across the island chain through Thursday morning, bringing isolated to scattered windward and mauka showers through this afternoon and scattered to numerous showers overnight into the morning hours. As drier air fills in behind it during the day on Thursday, shower coverage will decrease, with drier conditions expected through the weekend.

Breezy trades will gradually ease over the next couple of days as the ridge to the north of the state weakens. The transition to a lighter flow will allow for continued windward to mauka showers as limited moisture moves in on the trades, and the addition of leeward and interior clouds and showers as sea breezes develop each afternoon. Any showers during this period will likely be light and brief due to the limited available moisture.

Model guidance suggests that moderate to locally breezy trades will try to become reestablished by early next week as surface ridging builds northeast of the state. With the next band of moisture expected to arrive sometime Sunday night into Monday and more moisture building into the area by midweek, there will be periodic upticks in windward and mauka showers Sunday night onward.

AVIATION

Trade winds will ease slightly over the next couple of days as a surface ridge north of the islands weakens. A shallow pocket of moisture moving within the trades has been producing widespread MVFR ceilings and visibility in SHRA along windward and mauka areas from Big Island to Oahu, and AIRMET Sierra for mountain obscuration has remained posted for these islands today. Some improvement is noted on Oahu and Molokai, where the AIRMET may be dropped soon. The moisture is expected to linger through the night across windward Big Island and Maui, where the AIRMET will likely remain in effect. Drier conditions and prevailing VFR are expected Thursday.

MARINE

Surface ridge north of the area will weaken Thursday through Saturday as a front passes far north of the state. Moderate to fresh trades will ease to gentle to moderate category during this time. Fresh to locally strong easterly trades will return Sunday through early next week as the surface ridges strengthens north of the state.

Currently, a small, medium-period south swell is fading generating small, inconsistent sets along south facing shores and should be even smaller by Thursday. A series of small pulses of south- southwest swells will fill in late Thursday into Friday reviving near average surf along south facing shores.

Long-period energy from a storm that passed within our swell window around New Zealand earlier this week is expected to gradually fill in locally late Friday through the weekend. Wave models have this swell peaking Sunday into Monday that will drive surf heights near or above warning levels. This swell will coincide with the peak monthly tides and will likely lead to significant wave runup and minor coastal flooding during the first half of next week, particularly during the peak daily high tide cycles. South shore surf will remain elevated through much of next week due to the slow decline of this large south swell and a series of more overlapping southerly swells.

East shore surf will slowly decline below seasonal averages through the rest of the week and into the weekend as trades ease. Surf along east facing shores will pick up a notch next week as more breezy trades return. No significant swells expected elsewhere.

HFO WATCHES/WARNINGS/ADVISORIES

None.