Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
604 FXHW60 PHFO 310646 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 846 PM HST Sun Aug 30 2026 .SYNOPSIS... Breezy trades will continue through at least the middle of the week with showers generally favoring windward and mauka areas, particularly during the overnight through early morning hours each day. Tropical Storm Lowell remains over 800 miles ESE of the Big Island. Latest forecast track has Lowell passing south of the Big Island late Wednesday into Thursday. How close it passes south of the Big Island is yet to be determined. At the very least, we should see strong and gusty trade winds Thursday into Friday. && .UPDATE... No major changes this evening. Forecast still remains on track for an increase of low level moisture tonight, which will bring some passing showers over windward and mauka areas over the next few days. Any rainfall amounts should remain on the lighter side due to stable conditions aloft. Beyond Wednesday, the weather forecast will highly depend on the eventual track of T.C Lowell. Compared to yesterday, the global models seem to be coming into better agreement with Lowell passing south of the Big Island late Wednesday into Thursday. && .PREV DISCUSSION... Issued at 311 PM HST Sun Aug 30 2026 Benign trade wind pattern through at least Wednesday as strong longwave ridging approaching 594dm remains anchored near 170W longitude before migrating east during the latter portion of the week. This in turn favors expansive surface high pressure in maintenance of breezy trades through this time. An uptick in showers for windward and mauka is expected next week as moisture originating off the California coast entrains in the trades, reaching the islands around Wednesday. The tropics remain active with attention turning toward the Friday Sept 4th to Wednesday Sept 9th period. During this time, TC Lowell and TC Karina will make their approaches toward the islands within just a couple days of each other. During this time, uncertainty runs higher than normal owing to weak steering flow followed by the potential emergence of a closed upper low NW of the islands that will alter steering flow and introduce a component of shearing as well. TC Lowell and TC Karina both carry potential to come precariously close to the islands during this time window. For Lowell, the GFS remains on the northern side of the solution envelope while the new ECMWF, machine learning guidance, and official NHC forecast remain considerably further south. The forecast remains sensitive to upper air features that have yet to actually form and evolve so confidence remains low even as model consensus on a more southerly track has emerged. As TC Lowell tracks NW, Karina will be fast approaching from the east with a NW turn expected as well. Timing of this turn will be key and represents the primary forecast uncertainty for Karina which remains about a week out. Consult NHC for the official track and intensity forecast. An approach by Lowell that is sufficiently far south to prevent direct impacts to the islands will still bring elevated humidity and a high likelihood of gusty winds for Labor Day Weekend. && .AVIATION... A strong high pressure system north of the Hawaiian Islands will keep moderate to breezy trade winds in the forecast over the next several days. A unsettled band of clouds and showers will move into the islands over the next few hours, bringing periods of MVFR conditions mainly along the windward mountain areas through early Monday morning. These MVFR conditions will ease a few hours after sunrise. AIRMET Sierra was issued this evening for tempo mountain obscurations for north through east sections of all islands due to increasing low cloud and shower trends. AIRMET Tango remains in effect for mod low level turbulence south through west of island mountains. This turbulence AIRMET will likely continue for the foreseeable future. && .MARINE... Issued at 311 PM HST Sun Aug 30 2026 A strong surface high will remain nearly stationary far north of the Hawaiian Islands this week. Moderate to locally strong trade winds will prevail through the week. Tropical Cyclone Lowell may move into the Hawaiian Offshore Waters from Wednesday into Thursday. Wind and weather impacts and timing for the coastal waters, including wind waves and combined seas will be driven by the speed and track of Lowell as it moves towards the region. The current south swell will slowly decrease over the next several days. Overlapping small, long- and medium-period south swell energy will keep small surf along south facing shores through the week. The next boost in south swell energy will arrive and fill in from Tuesday to Wednesday at around 2 to 3 feet with an 18 second period. This swell will peak on Wednesday, just below south shore advisory thresholds, and then slowly decline through the end of the week. Trade wind swell energy will continue to keep elevated surf heights along all east facing shores through the coming week. Surf along east and southeast facing shores could become especially rough and choppy Thursday into Friday as Lowell passes by to the south. && .FIRE WEATHER... Issued at 311 PM HST Sun Aug 30 2026 Breezy trades continue through midweek and then strengthen Thursday through Saturday as TC Lowell passes south of the islands. Dewpoints increase into the 70s during this time in maintenance of elevated min RH values. The exact track of TC Lowell remains uncertain and thus potential for meaningful rainfall remains uncertain at this time. The inversion will hover between 6k-7kft the next couple of days. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 PM HST Tuesday for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters- Maalaea Bay-Pailolo Channel. && $$ UPDATE...Kino DISCUSSION...JVC AVIATION...Bohlin MARINE...TS