Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
605 FXHW60 PHFO 160145 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 345 PM HST Sat Jun 15 2024 .SYNOPSIS... Breezy trade wind conditions will persist through the new week, with clouds and showers favoring windward and mauka areas overnight and into the morning hours. Increased showers are possible Monday night through midweek due to an upper-level disturbance drifting westward across the state. Some showers may briefly extend to the leeward areas of the smaller islands. && .DISCUSSION... No changes to the forecast this afternoon. High pressure is expected to remain north of the islands through the new week, so expect the moderate to locally breezy trade wind pattern to continue. Afternoon soundings from Lihue and Hilo had the trade wind inversion between 7000 and 8000 feet, and precipitable water (PW) of 1.15 inches. Models suggest little change in the inversion height through the upcoming week, while an increase in PW is expected. The ECMWF shows an increase in PW by Monday morning persisting through Wednesday, a brief decrease Thursday and then another increase Friday. The GFS shows an increase by Tuesday morning through Wednesday, decrease Thursday, and then not as much of an increase Friday. In any event, the additional PW corresponds with a mid to upper level low forming over the islands and then drifting to the west. As such there could be some additional showers Monday through Wednesday. With the breezy trades, some of those showers could reach leeward areas at times. && .AVIATION... Moderate to locally breezy trade winds will continue. Clouds and light showers will favor east and northeast facing slopes and coasts. An increase of showers are expected tonight, which could bring periods of MVFR CIG or VIS along windward areas. AIRMET TANGO is in effect for low level turbulence leeside of terrain due to the gusty trade winds. AIRMET SIERRA will likely return tonight along windward areas due to an increase of clouds and showers. && .MARINE... High pressure centered far northeast of the state will maintain moderate to locally strong trade winds across the state over the next several days. As the high shifts westward and strengthens north of the state, trade winds will strengthen to fresh to near gales during the second half of next week. A Small Craft Advisory (SCA) remains in effect for the windier channels and waters around Maui County and the Big Island through the weekend. This SCA for the windier waters will likely continue and expand in coverage during the second half of next week. Surf along south facing shores will remain at High Surf Advisory thresholds (10 feet for south facing shores) through tonight. Surf heights will continue to gradually decrease as the swell fades during the next few days. Mainly background energy is expected by the middle of next week. A gale force low currently near 45S145W could produce a small S to SSE swell next weekend, although most of the energy is aimed well east of the islands. North shore surf will remain small for the next few days. Small medium period northwest pulses may provide a tiny bump from Sunday night into middle of next week. Surf along east shores will remain small and choppy throughout the first half of next week. An increase is expected during the second half of next week as the trades strengthen. && .HFO WATCHES/WARNINGS/ADVISORIES... High Surf Advisory until 6 AM HST Sunday for Niihau-Kauai Leeward-Waianae Coast-Kahoolawe-Maui Leeward West-Kona-Kauai South-East Honolulu-Honolulu Metro-Ewa Plain-Molokai Leeward South-Lanai Leeward-Lanai South-Maui Central Valley South-South Maui/Upcountry-South Haleakala-Big Island South-Big Island Southeast. Small Craft Advisory until 6 PM HST Monday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...M Ballard AVIATION/MARINE...Kino