FXHW60 PHFO 260655 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 855 PM HST Mon May 25 2026 .SYNOPSIS... A broad ridge of high pressure north of the Hawaiian Islands will dominate our weather with continued moderate to locally strong trade winds. An upper level trough east of the islands may help enhance trade showers the next few days. A new mid week upper level low moving in west of the islands may pass over the state Friday into Saturday. This feature may enhance showers. && .SHORT TERM UPDATE... As mentioned in this afternoon's discussion, trade magnitudes are still up but more significant over the better exposed windward locales and open waters. Overall, winds have noticeably fallen off across many leeward communities. Today's wind behavior of sustained 15 to 20 mph with gusts to near 30 mph over windward exposures...10 to 15 mph with gusts around 20 mph leeward...will be the standard the next several days. Reasoning is that there will be little change in the near 10 mb pressure gradient over the islands from regenerative surface highs tracking east along 40N latitude through the remainder of the week. Rainfall will be the typical summertime seasonal variety as pockets of moisture riding in on the trades drop a few hundredths of an inch upon their quick western passage (a wee bit more rain within higher terrain). Fairly dry through Thursday with the wettest, more cloudier days of the week occurring at it's close. An upper level low passing overhead Friday into Saturday will destabilize the atmosphere just enough (cooling 5H from -5 C Tuesday to near -10 C late Friday), in tandem with a band of slightly higher mid level moisture passing in from the northeast, to garner a mention of more inclement late week weather. && .PREV DISCUSSION... Issued at 338 PM HST Mon May 25 2026 There has been some further tweaks to the winds for the week to bring them in better alignment with the latest model runs, that suggest winds will remain a touch stronger than previously anticipated. Otherwise the forecast remains the same as the update issued earlier today. Satellite shows some showery clouds riding in on the trade wind flow. A ridge far north of the islands will remain in place into the middle of the week, with the pressure gradient over the islands steady. As mentioned this morning, some of the high resolution models would suggest some areas could reach advisory levels winds in the next couple of days, but continue to feel this is not representative of overall conditions. The afternoon sounding from Hilo The overnight 12Z sounding from Hilo showed a fairly strong temperature inversion around 7,500 feet, while the Lihue sounding had a weaker inversion around 6,000 feet. High pressure at the surface will linger through the week, with some weakening of the pressure gradient over the islands during the second half of the week. An upper level low has formed about 900 miles to the northwest of Kauai, and is expected to move towards the islands this week. The global models suggest that this could help to enhance trade wind showers at the end of the week. At this time, the global model thunderstorm probabilities are not impressive. Additionally, near normal 500 and 700 mb temperatures are expected in the global models. The GFS brings in higher precipitable water than the ECMWF near Maui County and the Big Island for the upcoming weekend. At this time it would seem the upper low/trough could enhance trade winds, but not expecting much beyond that based on the current model runs. && .AVIATION... Issued at 338 PM HST Mon May 25 2026 Moderate to breezy trades will continue for the next few days. Low cigs and SHRA possible over windward and mauka locations. MVFR conditions possible in SHRA, otherwise VFR prevails. AIRMET Tango remains in effect for mod low-level turbulence over and downwind of terrain across all islands. && .MARINE... Issued at 338 PM HST Mon May 25 2026 Fresh to strong easterly trades will persist through the first half of the week as a strong surface ridge remains north of the state. This will allow the Small Craft Advisory to continue across most Hawaiian coastal waters through midweek. Expect a gradual downward trend through the second half of the week and into next weekend due to a weakness forming in the ridge as a front passes far to the north. Surf along south-facing shores will gradually lower tonight as a lingering medium-period south swell fades. A fresh long-period south swell will arrive Tuesday, then build to near the seasonal average through midweek before slowly easing Thursday. A more significant long-period south-southwest swell is expected by next weekend due to a storm-force low that passed southeast of New Zealand over the weekend. Satellite data showed a large fetch of 40 to 50 kt winds generating seas of 35 to just over 40 ft, focused toward, or just east of Hawaii along the 190-degree directional band. Expect surf to begin building locally Friday with 20+ second forerunners, then peak above/around the advisory level over the weekend. For the long range, expect a similar trend to persist through the first week of June as the active pattern persists within our swell window around New Zealand. Surf along exposed north- and west-facing shores will also continue to lower tonight as a small lingering north-northwest swell fades, but will trend up once again on Tuesday as the late season North Pacific activity continues. Although the bulk of the energy from this next swell will be focused northeast of the islands, expect long-period forerunners to arrive Tuesday, then fill in down the island chain through midweek. Above-average surf is likely by daybreak Wednesday near the peak before lowering Thursday. Surf along east facing shores will remain rough through midweek, then gradually lower later in the week as the trades ease. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 AM HST Wednesday for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters- Big Island Windward Waters-Kaiwi Channel-Kauai Channel-Kauai Leeward Waters-Kauai Northwest Waters-Kauai Windward Waters- Maalaea Bay-Maui County Leeward Waters-Maui County Windward Waters-Oahu Leeward Waters-Oahu Windward Waters-Pailolo Channel. && $$ SHORT TERM UPDATE...Blood PREV DISCUSSION...M Ballard AVIATION...Evans MARINE...Farris