Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
597 FXHW60 PHFO 180133 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 333 PM HST Tue Jun 17 2025 .SYNOPSIS... High pressure to the northeast of the Hawaiian Islands will remain in place and strengthen by the end of the week. Breezy trade winds and a typical windward and shower distribution can be expected with occasional pockets of showers, mainly during the night time hours. Conditions could then become drier and more windy by the weekend, followed by moderately wet trade winds next week. && .DISCUSSION... Passing showers have been observed today on radar and satellite imagery over windward and mountain areas. The sounding from this afternoon shows moderately moist air beneath a 6,000 to 8,000 ft inversion, which should support continuing trade wind showers this afternoon and tonight. Our airmass is expected to dry out by tomorrow and periodically fluctuate between periods of slightly wet and dry through the rest of the week, with showers focusing primarily over windward and mountain areas. Wind speeds appear to hold steady today before gradually decreasing a notch tomorrow through Friday into the moderate to locally breezy range. The next batch of enhanced trade wind moisture looks to arrive around Thursday night through Friday morning before drying out by Friday evening. This weekend, high pressure northeast of the islands is forecast to strengthen, which could cause trade wind speeds to increase to breezy to strong levels. Additionally, a strong mid level ridge could move overhead along with a dry airmass. This could inhibit clouds and showers, as well as lower the relative humidity. These factors combined could increase fire risk, with a KBDI at Honolulu of 508, conditions won`t quite be at red flag warning criteria, however there will still be a risk for enhanced fire weather conditions. More confidence will emerge as the weekend draws closer. By early next week, dry conditions could be replaced by a wetter trade wind pattern as global models indicate an upper level low along with slivers of enhanced low level moisture could move in from east to west. && .AVIATION... Breezy trade winds with brief passing showers will continue through tonight. Wind speeds will decrease to more moderate levels from Wednesday onward. Shower activity will be limited to windward and mountain areas, favoring the overnight to early morning hours. AIRMET Sierra may be needed again for mountain obscuration for some islands again tonight if shower activity becomes widespread enough. AIRMET Tango remains in effect for moderate turbulence over and south through west of the mountains. These stronger winds and turbulent conditions will likely continue into Wednesday. && .MARINE... High pressure north of Hawaii will slowly move eastward and drive fresh to strong trades across the local waters. A Small Craft Advisory (SCA) is in effect for windier waters and channels near Maui and the Big Island due to strong winds. Trade winds are forecast to strengthen this weekend. A small, long period, south swell will arrive on Wednesday and bring a slight bump up in surf through the weeks end. Rough and choppy conditions along east facing shores will through the next week. Surf will remain nearly flat along north facing shores. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 PM HST Wednesday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...Tsamous/Kino AVIATION...TS MARINE...Foster