800 FXHW60 PHFO 091314 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 314 AM HST Mon Jun 9 2025 .SYNOPSIS... A high pressure ridge north of the state will remain fairly weak due to a lingering stationary front over the Central Pacific Basin. Light to moderate easterly trade winds will continue through Tuesday. By Wednesday trade winds will strengthen into the moderate to locally breezy range as the ridge builds north of the islands. Expect even stronger trade winds this weekend. && .DISCUSSION... Satellite imagery this morning shows moderately unsettled open cell cumulus clouds moving into the islands on the easterly trade winds. These clouds will produce brief periods of showers this morning mainly over the windward and mountain areas. Shower activity will decrease in coverage after 9 AM HST due to more stable diurnal trends. Farther north a stationary front lingers just south of the subtropical ridge, and a low level trough is just west of the islands. Both of these trough features will serve to weaken the winds over the islands with a slight east-southeast shift in prevailing wind direction near Kauai. Temperature inversion heights range from 6,000 to 7,000 feet elevation in this mornings 2 AM HST (12Z) upper air balloon soundings at Lihue and Hilo respectively. Overall a fairly stable weather pattern will remain in place under the influence of a stable ridge aloft lasting into the weekend. The biggest weather changes are the increasing winds later this week, up a notch on Wednesday into moderate to locally breezy range, and then becoming breezy trade winds over the weekend. The rainfall pattern will follow the typical diurnal trends with higher shower coverage in the overnight to early morning hours, and then less shower activity during the mid morning through afternoon time period. Any showers will favor windward and mountain areas. && .AVIATION... The high pressure ridge north of the Hawaiian Islands will continue to produce light to moderate trade winds through Tuesday. A hybrid sea breeze and trade wind pattern will develop over each island, with daytime sea breezes developing along terrain sheltered western mountain slopes. Brief passing showers are possible over windward and mountain areas, favoring the overnight to early morning hours. VFR conditions will prevail through Tuesday. AIRMET for mountain obscuration in effect for north through east sections of Oahu. These low clouds will diminish around 9 AM HST or 19Z. && .MARINE... A high pressure ridge will remain far north of Hawaii over the next several of days, then set up northeast of the state towards the end of the week. A developing trough northwest of the state will briefly cause trade winds to veer east- southeast today. As the trough moves away, trades will gradually strengthen with moderate to locally strong trade winds returning by the middle of the week. A Small Craft Advisory could return to the typical windy areas around Maui County and the Big Island as early as Tuesday or Wednesday. As the ridge strengthens, widespread fresh to strong trade winds are possible this weekend. The current south-southwest (200 degree) swell peaked last night into this morning and continues to slowly decline through the middle of the week. A small south-southwest swell is possible Friday into the weekend. Surf along east facing shores will remain moderate as the short- period northeast swell holds through today. Trade winds will gradually strengthen throughout the week, which will bring an increase of rough and choppy waves towards the second half of the week. Windswell will continue to increase over the weekend due to strong trade winds. A trough located north of the state could produce small short- period energy out of the north Tuesday through the middle of the week. && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Bohlin AVIATION...Bohlin MARINE...Walsh