Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
014 FXHW60 PHFO 170647 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 847 PM HST Sun Jun 16 2024 .SYNOPSIS... A high pressure ridge will remain locked in place north of the Hawaii region through the rest of this week. A weak upper low over the state will help produce brief periods of showers mainly over the windward and mountain areas in the overnight to early morning hours. The ridge to the north will strengthen with slightly stronger easterly trade winds from Wednesday on into next weekend. && .DISCUSSION... Radar imagery this evening shows scattered showers developing over and upstream of windward mountain ranges. Satellite imagery shows a band of clouds moving into east Maui and the windward Big Island that will likely spread periods of showers along the windward slopes of both islands through the early morning hours. A weak upper level low is lifting trade wind inversion heights this afternoon, where they ranged from 6,000 feet at Lihue and 7,000 feet at Hilo. Temperature inversion heights at this level will support typical trade wind showers favoring the windward and mountain areas. A subtropical high pressure ridge north of the Hawaiian Islands will produce moderate to breezy trade winds lasting through the week. A slight increase in the easterly trade wind breezes will start on Wednesday and continue into next weekend as the ridge north of the islands strengthens slightly. A cloud band from the likely remnants of an old East Pacific front may roll through the islands by next Saturday, enhancing shower activity a bit for next weekend. Otherwise not much changes are forecast in the day to day island weather pattern with just more typical trade wind weather to continue through the end of this week. && .AVIATION... Breezy easterly trades will continue, with clouds and brief showers favoring windward and mauka locations. Periods of MVFR conditions will be possible over these windward sections, particularly overnight through the morning hours. Otherwise, VFR conditions will prevail. AIRMET Sierra for tempo mountain obscuration may be needed for windward areas later tonight, mostly over the eastern end of the state where a decent sized area of moisture/low clouds is moving in. AIRMET Tango is in effect for tempo moderate low level turbulence lee of the island terrain across the state due to breezy trade winds. && .MARINE... Surface high pressure will remain north-northeast of the area, then gradually strengthen through the week. As a result, the trades will become fresh to locally strong, with near-gale winds in the Alenuihaha Channel and waters south of the Big Island on Wednesday. The Small Craft Advisory (SCA), currently in effect for the normally windier areas around Maui County and the Big Island, will likely continue through the week, with an expansion to include the waters around Kauai and Oahu on Wednesday. Surf along south facing shores will continue to slowly decline as the south swell fades through Monday. For the rest of the week, expect only background small, medium to long period, south to southeast swell energy moving through the local waters. North shore surf is expected to be small through the week, coming from small, mainly medium-period, northwest swells. Surf along east shores will become increasingly rough and choppy from Wednesday onward as the trade winds strengthen across the state. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 PM HST Tuesday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...Bohlin AVIATION...Gibbs MARINE...TS