FXHW60 PHFO 191913 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 913 AM HST Tue May 19 2026 .SYNOPSIS... An unstable and somewhat wet trade wind pattern will continue through tonight, with brief downpours possible. From Wednesday into early next week, an area of high pressure north of the islands will push drier air into the region. Trades are expected to become windy by Thursday and Friday, then will gradually ease back to locally breezy levels this weekend. && .SHORT TERM UPDATE... Isolated showers were moving west over mainly windward and mauka areas this morning, and skies were partly to mostly cloudy over most of the state. Winds were averaging 5 to 15 mph with a few higher gusts in the usual windy spots. We expect a few moderate to briefly heavy showers this afternoon, but probably not as heavy as yesterday as moisture is a little lower today. All this is handled well by the current forecast and no changes are planned at this time. && .PREV DISCUSSION... Issued at 341 AM HST Tue May 19 2026 Early this morning, local radar imagery shows just a few light scattered showers moving into the islands on locally breezy easterly trade wind flow. Similar to the day prior, the heavier showers that occurred at select spots yesterday quickly diminished during the late afternoon and evening, leaving only light, isolated showers favoring windward areas overnight. Regional satellite imagery early this morning does show a few bands of moisture upstream of the state, however, and although moisture content has decreased from the previous couple of days, the early morning 12z soundings from Lihue and Hilo still show ample precipitable water available. Drier air is forecast to arrive from tonight into Wednesday night as high pressure north of the state strengthens. In the meantime, expect a relatively wet trade wind weather pattern to continue, with moderate to briefly heavy rain from showers that will generally favor windward and mauka areas, as well as the Kona slopes of the Big Island during the afternoon. From late Wednesday onward, precipitable water values are anticipated to decrease back down to around 1 inch, and this drier air will persist into next week. Increased stability and stronger trade winds are expected by Thursday. Latest global guidance remains in good agreement with the high to our north strengthening, which should result in windy conditions across the region. Winds could potentially reach Wind Advisory levels Thursday into Friday for some areas, then decreasing back to locally breezy levels during the second half of the weekend. && .AVIATION... Moderate to locally fresh trade winds will persist today and increase on Wednesday as the atmosphere gradually becomes more stable. Periods of MVFR conditions will primarily affect windward mountain areas, though an isolated heavy shower could develop over leeward terrain this afternoon. No AIRMETs are in effect. We will monitor for potential mountain obscuration across windward areas. Increasing trade winds and stability will eventually require AIRMET Tango for low level turbulence over and downwind of terrain. && .MARINE... Locally fresh trades become strong to locally near-gales during the latter half of the week. The Small Craft Advisory (SCA) remains in effect and will eventually be expanded to all waters as winds and seas build later this week. Small, short to medium period NNW swell will fill in today. This will be followed by a small NNW swell emanating from a strong low near the Aleutian Islands by late week. A series of small, long period SSW swells supports near-average surf along S shores. Meanwhile, strengthening trades maintain elevated surf and short period fresh swell along E facing shores into next week. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 PM HST Wednesday for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters- Maalaea Bay-Pailolo Channel. && $$ DISCUSSION...Vaughan AVIATION...Wroe MARINE...JVC