Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
441 FXHW60 PHFO 151946 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 946 AM HST Sat Jun 15 2024 .SYNOPSIS... Breezy trade wind conditions will persist through next week. Clouds and showers will predominantly favor windward and mauka areas overnight into the morning as areas of moisture moves through. An increase in windward shower coverage is possible from Monday night through midweek due to a mid-to upper-level disturbance drifting westward across the state. Some of these showers may briefly extend to the dry leeward areas of the smaller islands. && .DISCUSSION... Guidance remains consistent, showing a strong surface ridge north of the state throughout the upcoming week, possibly strengthening later on. This will sustain breezy easterly trade winds with clouds and mostly brief showers favoring windward and mauka locations. The trade wind inversion will be situated between 6,000 and 7,500 feet, and precipitable water (PW) levels will generally range from 1.0 to 1.25 inches. Rainfall amounts will likely be limited, even in windward areas, except possibly during the first half of the week when an upper-level trough moves westward across the state, drawing up more moisture. Guidance indicates PW values increasing above average starting Monday night through Tuesday in the eastern part of the state, and later spreading to the western areas by Tuesday night into midweek. While most showers during this period will favor windward and mauka areas, some could reach leeward areas, especially Tuesday night into Wednesday. This pattern of occasional light showers in our typically dry leeward regions may persist into the latter part of next week as the pressure gradient tightens, resulting in brisk easterly trades across the islands. && .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 now in effect due to a slight strengthening of the trade winds and a stronger inversion. AIRMET Sierra will likely return tonight along windward areas due to an increase of clouds and showers. && .MARINE... A ridge of high pressure north of the islands will keep moderate to locally strong trade winds blowing across the Hawaii region. 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 into much of next week. The High Surf Warning (HSW) for south facing shores has been downgraded to a High Surf Advisory (HSA) due to a drop in swell heights locally. Latest observations show swell heights of around 4 to 5 ft and 15 seconds. This swell should gradually decline over the next several days and return to background levels by midweek. 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 PM HST this evening for south facing shores of Niihau, Kauai, Oahu, Molokai, Maui, Kahoolawe and Big Island. Small Craft Advisory until 6 PM HST Sunday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...Foster AVIATION/MARINE...Kino