Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
533 FXHW60 PHFO 260202 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 402 PM HST Fri Jul 25 2025 .SYNOPSIS... Trades will ease to gentle to moderate strength into the weekend in response to an approaching weak surface trough from the east, An increase in mainly windward and mauka rainfall is possible along this dissipating feature late Saturday into Monday. Trades will strengthen again around Tuesday or Wednesday. && .DISCUSSION... Trades will ease to gentle to moderate strength into the weekend in response to an approaching weak surface trough from the east. While this trough is progged to dissipate upon reaching the islands, the associated moisture escorted by the trough may be just enough to increase humidity levels and prompt a greater chance for windward showers across Big Island and possibly Maui County during the latter half of the weekend, and then further north into Oahu and Kauai by early next week. Otherwise, shower activity will be limited and primarily across windward and mauka areas, with exception to the South Kona slopes during the afternoon periods. Latest model guidance continues to depict trades strengthening back to moderate to locally breezy by Tuesday or Wednesday of next week, however, with uncertainty persisting with regards to tropical development south of Hawaii, confidence of the forecast remains low. That said, the likeliness of breezy trades within drier conditions is high. && .AVIATION... Moderate trades will ease slightly to gentle to moderate trades Saturday and Sunday. A relatively stable and dry pattern will hold through in Saturday. Expect predominately VFR conditions across the Hawaiian Islands, however, brief periods of isolated showers across windward and mountain areas remain possible. A weakening trough moving from east to west may possibly increase chance of low level clouds and precipitation and thus MVFR conditions first for the windward areas the Big Island Saturday afternoon then for the rest of the state by Saturday night into Sunday. There currently are no AIRMETs in effect. && .MARINE... High pressure north of the area has weakened today allowing for moderate to locally fresh trades. The high will further weaken this weekend, easing wind speeds to gentle to fresh. Moderate to strong trades then return next week as high pressure restrengthens and a tropical disturbance tracks south of the state. Small background S swell keeps surf from going flat along S shores through early next week. A storm force low E of New Zealand is producing seas up to 40 feet per JSON satellite observations indicating undersimulation of winds by the model guidance. Confidence is therefore increased that this low will generate a moderate long period S swell that approaches or exceeds the High Surf Advisory threshold during its peak. Choppy surf along E facing shores will trend down into the weekend as winds ease locally and upstream. Flat to tiny surf expected along N facing shores through the forecast period. Peak afternoon high tides combined with elevated water levels are running about half a foot higher than predicted. This trend will continue through this afternoon and could lead to minor flooding along the shoreline and in low lying coastal areas of Maui County and the Big Island. Water levels then lower for the weekend. && .FIRE WEATHER... Dry and stable conditions will persist through Saturday, and locally breezy trade winds will ease slightly. A shallow area of moisture moving in from the east should bring an increase in humidity late Saturday into Monday, further decreasing fire weather concerns. Trade winds are expected to restrengthen Tuesday or Wednesday, with developing dry conditions reestablishing, may result in elevated fire weather concerns && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Foster AVIATION...Almanza MARINE...JVC FIRE WEATHER...Foster