Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
817 FXHW60 PHFO 300646 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 846 PM HST Sun Sep 29 2024 .SYNOPSIS... Moderate trade winds with passing overnight to early morning showers will continue through the end of the week. A slight increase in showers may develop from Tuesday night to Wednesday morning, especially over the eastern islands. && .DISCUSSION... A fairly stable cloud pattern shows up on satellite imagery this evening. A few bands of unsettled clouds are noted farther upstream from the island chain, these passing cloud bands will slightly increase shower activity starting on Monday. Upper air balloon soundings from 2 PM HST this afternoon show subsidence inversion heights in the 5,000 to 6,000 foot range. For most of the week we will see passing showers mainly over windward and mountain areas of each island, favoring the typical overnight to early morning hours. One wrinkle in this rainfall forecast will occur from Tuesday night to Wednesday as a weak disturbance moves from east to west down the island chain. Expect shower coverage to increase during this time period, especially over the eastern half of the state. Fairly stable trade winds will swiftly return by Wednesday afternoon and linger into the weekend. && .AVIATION... Surface high pressure northeast of the state will generate light to moderate trades through the forecast period. Expect limited low clouds and light showers along windward and mauka areas. Brief MVFR possible within any heavier showers, otherwise VFR prevails. No AIRMETs are currently in effect. && .MARINE... High pressure north and northeast of the islands will keep moderate to locally fresh trades in place through Thursday. Wind speeds may flirt with Small Craft Advisory criteria in the windier channels at times, but will likely not be consistent enough to warrant the issuance of a SCA. The trades will ease into the light to locally moderate range Friday through the weekend as the ridge north of the state weakens. A small, medium period north swell will gradually decline through Monday. A new small, medium period northwest swell should arrive Monday night, peak late Tuesday and Tuesday night, then decline as it shifts more northerly Wednesday and Thursday. Several additional small north swells should maintain small surf along north facing shores Friday through next weekend. A series of small long-period southwest swells should provide some small but inconsistent surf along south facing shores through Monday. A slightly larger south-southwest swell should fill in Tuesday, hold through Wednesday, then gradually decline through the rest of the work week. A small to moderate sized long-period south-southwest swell will gradually fill in late Saturday and Saturday night, then peak with swell heights of 3 to 4 feet next Sunday and Monday. This swell will give a sizable late season boost to south shore surf, potentially reaching advisory levels. East shore surf will remain small through most of this week, although select spots with more northerly exposure could see some of the north swells throughout the week. && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Bohlin AVIATION...JT MARINE...Jelsema