Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
839 FXHW60 PHFO 121918 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 918 AM HST Sat Sep 12 2026 .SYNOPSIS... Drier trade winds will prevail into early next week with light showers on the windward side of the islands. A weak disturbance will lift out of the deep tropics towards the middle of next week bringing a slight uptick in trades, increased humidity, and a better chance for showers. && .SHORT TERM UPDATE... Dry and stable trade winds expected through the weekend, with a few spotty afternoon showers across leeward Big Island. No updates to the forecast for this morning. && .PREV DISCUSSION... Issued at 303 AM HST Sat Sep 12 2026 Morning satellite water vapor imagery shows a large upper level low well northeast of the state and generally dry northwest flow aloft as a weak short wave moves southeast over the area. Remnant moisture and showers remain west and southwest of the Big Island and will gradually dissipate through the morning. Drier air in prevailing trade winds will continue through the weekend. Typical trades weather is expected over the next few days with occasional light showers across the windward side of the islands each day. A tropical disturbance currently several hundred miles southeast of Hilo will move northwestward over the next several days. NHC forecast has dropped to a 10% chance of development into a tropical cyclone over the next 7 days. Most likely scenario is for this feature to help pull tropical moisture into the area, though how much and when will depend on its track. For now expect precipitable water and dew points to increase once again with a small increase in trade winds and higher precipitation chances towards the middle of next week. Tropical Storm Norbert is currently around 1760 miles ESE of Hilo, moving west-northwest at 10 mph. This system is now forecast to remain at Tropical Storm strength through Wednesday, when it will still be southeast of Hawaii. There remains higher than normal uncertainty on where this storm will track as it approaches, so confidence in impacts - if any - to the islands remains low. && .AVIATION... A large upper level low centered approximately 1,200 miles northeast of the islands is weakening the pressure gradient and therefore the trade winds near Hawaii. These weaker trades will continue through the weekend. Winds may become light enough within more wind- protected leeward areas to initiate local breezes. Relatively dry air is working its way in across the state and will limit shower activity. && .MARINE... Moderate to locally fresh trades will continue through early next week before gradually strengthening through the latter half of the week. Moisture associated with a trough moving in on the trade wind flow may bring an increase of showers to the coastal waters Tuesday into Wednesday. Surf along south-facing shores will gradually decline through the weekend as the small, medium- to long-period energy slowly fades. A moderate, long-period swell generated by a low that passed near Australia and New Zealand is forecast to arrive mid to late week next week. Surf along east-facing shores will remain small to moderate through the forecast period due to the moderate to fresh trade winds. Flat to tiny surf along north facing shores is expected through the forecast period. && .FIRE WEATHER... Issued at 303 AM HST Sat Sep 12 2026 Fire weather risk will remain low the next several days due light to moderate winds and the effects of recent rainfall. Inversion heights are expected to remain elevated or weak through Monday. && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM UPDATE...Foster PREVIOUS DISCUSSION...SS AVIATION...Parker MARINE...Farris FIRE WEATHER...SS