Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
861 FXHW60 PHFO 200157 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 357 PM HST Tue Aug 19 2025 .SYNOPSIS... Moderate to locally breezy trade winds will continue through the rest of this week as high pressure builds over the region. A subtle increase in windward and mauka showers is possible on Wednesday, but in general, expect mostly dry and stable conditions into the weekend. && .DISCUSSION... Latest radar and satellite imagery this afternoon shows mostly dry conditions prevailing across the islands with relatively few clouds and almost no showers as high pressure builds over the region. Moderate to locally breezy trade winds are observed at most locations, with the highest gusts generally in the 20 to 30 mph range. Afternoon soundings from Hilo and Lihue show the trade wind inversion between 5000 and 6000 feet. Guidance indicates that ridging will remain in place for the next several days, which will continue the breezy trades through the end of the week. As previous discussions have mentioned, guidance continues to show that a subtle plume of moisture will move across the islands during the day on Wednesday, which may bring a slight increase in clouds and showers over windward and mauka areas (though this would be subtle). Other than this, however, an overall dry trend will continue through the week with the typical summertime trade wind weather and dry, stable conditions. With the dry and breezy conditions throughout the rest of this week and into the weekend, we could see elevated fire weather concerns, especially across leeward areas. Next week, a plume of moisture embedded within the trades could move into the islands by Monday or Tuesday, increasing windward and mauka clouds and showers once again. && .AVIATION... Moderate to locally breezy trades will persist through the forecast period. Low cigs and SHRA are possible over windward and mauka areas. MVFR conds possible in SHRA, otherwise VFR prevails. No AIRMETs are in effect at this time. AIRMET Sierra may be needed overnight due to potential increases in low clouds and SHRA along windward and mauka regions. AIRMET Tango will continued to be monitored for low level turbulence. && .MARINE... A ridge of high pressure far north of the state will maintain fresh to locally strong trade winds throughout the forecast period. A Small Craft Advisory (SCA) is in effect for the windier waters and channels around Maui County and the Big Island through tonight and will likely persist throughout the week and into the weekend. A series of small, medium period south (170-190 degree) swells are expected throughout the week with surf around the summer average expected late Wednesday through around Saturday. Surf heights should decrease Sunday into early next week as these swells fade. Choppy conditions will continue for east-facing shores through the forecast period due to the persistent fresh trades. Surf along north facing shores will remain nearly flat through the forecast period. Peak high tides associated with the lunar cycle will lead to minor coastal flooding along shorelines and low lying coastal areas during the next few afternoons. A Coastal Flood Statement is in effect for minor coastal flooding this week. && .FIRE WEATHER... Moderate to locally breezy trade winds are expected as high pressure builds over the state. Satellite imagery and latest guidance shows direr air filtering into the region as inversion heights lower to around 5,000 to 6,000 feet. Despite lowest relative humidities dipping as low as the mid 40s during the afternoon hours each day, wind speeds look to be a limiting factor, so not anticipating any fire weather headlines at this time. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 PM HST Thursday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...Vaughan AVIATION...JVC/DT MARINE...Kino FIRE WEATHER...Vaughan