textproduct: Honolulu

SYNOPSIS

Trades remain weak through Friday as a trough advances north of the islands. Tropical Depression 2C has formed southeast of Hawaii and is forecast to track south of the area early next week bringing strengthening winds and potential for heavy rainfall, especially to the eastern end of the state.

SHORT TERM UPDATE

Surface troughing associated with tropical remnants positioned immediately north of the Hawaiian islands will advance NW during the next 24 hours. This will substantially weaken the gradient leading to very light winds, expanding sea breezes, and muggy weather with dewpoints in the low 70s. A few afternoon showers over leeward areas will be possible today and tomorrow with light trades delivering limited showers windward overnight. Bumped pops downward accordingly to highlight relatively dry weather for this period. Benign trade wind weather then prevails into Saturday, though trades likely undergo strengthening becoming breezy to locally strong during this time as TD 2C gradually lifts out of the deep tropics and advances WNW or NW during the weekend. Will reserve additional commentary on this system until the afternoon package.

PREV DISCUSSION

Issued at 508 AM HST Thu Aug 20 2026

Weak trade winds today will allow for a sea breeze to develop, increasing chances of showers in some leeward areas. Winds will increase late Friday and veer easterly. Typical trade showers will return over windward and mauka areas, most common at night. Forecast for Saturday will be influenced by how the tropical system to the east-southeast of the state evolves. Current forecast maintains typical trade wind showers and increasing winds.

Tropical Depression Two-C has developed 960 miles east-southeast of Hilo. The first look at the potential track keeps the storm south of the Big Island, but it is still early in the forecast process and the track could shift either north or south in coming advisory cycles. Impacts from rain, wind, and surf can be experienced well outside the center of the storm so do not focus too much on the exact track. Current guidance indicates that precipitation will increase on the east side of the state Saturday night into Sunday, spreading west Sunday night into Monday. The timing, direction, and magnitude of the strongest winds remain highly dependent on the track and intensity of the system.

In anticipation of critical new updates with each of the advisory packages issued by the National Hurricane Center (NHC), NWS Honolulu will delay the issuances of our typical forecast package products (AFD, SFT, PFM, ZFP, SRF, CWF, etc) until after the release of NHC's suite of products, to incorporate the latest and most up-to-date information on Tropical Depression Two-C.

AVIATION

A surface trough moving from east to west through the islands today will keep winds light enough for local land and sea breezes to set up. Afternoon clouds and showers are expected over the interior of the islands, with some MVFR conditions possible. Some clearing of the clouds and showers are expected overnight. However with weak trade wind flow setting up behind the trough, some clouds and showers will set up over windward and mauka areas. VFR conditions are expected to prevail, except those pockets of MVFR in clouds and showers.

No AIRMETs are currently in effect, and none are expected through Friday night.

MARINE

A trough just northeast of the islands will track northwestward across the offshore waters, leading to a period of light and variable winds for most waters today. By late Friday, moderate to locally fresh trades will begin to build back into the region as the trough exits to the northwest, high pressure drifts southward closer to the island chain, and Tropical Depression Two-C nears the state from the southeast. The forecast for this weekend will depend significantly on the uncertain track of this tropical cyclone.

Surf along south facing shores will remain slightly below average through Thursday. A long period south-southwest swell generated from gales just south and east of New Zealand will begin arriving later today into Friday, boosting surf to near or slightly below average by Saturday. Surf along east facing shores also remains below average with weak trades, then builds this weekend as the trades restrengthen. Surf along east- and south-facing shores will be compounded by a southeast swell generated by Tropical Depression Two-C that will build through Sunday and may persist through early next week. This short-period tropical swell could cause surf to approach advisory levels along east facing shores of the Big Island Saturday night into Sunday. North facing shores will remain tiny through Friday, with a slight bump from Lala swell possible this weekend.

FIRE WEATHER

Issued at 508 AM HST Thu Aug 20 2026

Trade winds will weaken today, increasing chances of showers for the leeward side of the islands. Trade winds increase over the weekend with showers switching to windward. The inversion is 6000 to 7000 ft. Increased wind and rain possible across the state late in the weekend into early next week.

HFO WATCHES/WARNINGS/ADVISORIES

None.