Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
390 FXHW60 PHFO 110217 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 417 PM HST Wed Jul 10 2024 .SYNOPSIS... Trade winds will be breezy to windy into next week, delivering brief showers that will focus windward and mauka. && .DISCUSSION... Breezy to windy trades will prevail into next week, supported by a persistent surface ridge far N of the islands. The trade winds will deliver brief showers, mainly to windward areas, while most leeward areas will remain dry. The Kona slopes will receive their typical summertime afternoon and evening clouds and showers. The gradient aloft between a westward-moving mid-level trough E of the area and a mid-level ridge to the N is bringing strong NE-E winds to the Big Island Summits, where a Wind Advisory remains posted. Summit winds will diminish through Thursday as the weakening trough nears the islands. The trough may also weaken our persistently strong subsidence inversion, but not significantly. With the gusty trades aiding orographic lift, the passing trough could lead to a period of enhanced windward shower coverage from Thursday night through Friday night. Otherwise, randomly distributed clusters of stable and showery low clouds will periodically move through, modulating sky and shower coverage as they do so, especially windward. && .AVIATION... Breezy to locally windy trades will continue for the next couple of days, with passing showers favoring favor windward and mauka areas. Expect mainly VFR with brief MVFR conditions in showers/low clouds. AIRMET Sierra will likely be needed again tonight for mountain obscuration as windward showers increase. AIRMET Tango for low-level mechanical turbulence will remain in effect for the next couple of days due to the breezy trades. && .MARINE... Broad surface high pressure generally paralleling 40N will persist through the remainder of the week. This will create a tight enough pressure gradient across the local waters to maintain fresh to locally strong trade winds. Trades may reach gale force in gust around the notoriously windier bays and channels surrounding Maui County and Big Island. The anticipation of more widespread strengthened trades has expanded the Small Craft Advisory (SCA) to cover all Hawaiian Waters through Friday morning. The SCA should remain in effect the next several days as trades are expected to remain fresh to locally strong through the weekend. A series of small, medium period south southwest swells will slowly decline through the day but reinforcing similar swells will arrive through Friday afternoon. A storm force low that produced very high seas east of New Zealand earlier in the week will be the impetus to the next mentionable long period south southwest swell scheduled to arrive this weekend. This swell may push surf heights to near High Surf Advisory levels along south-facing shores during its peak Sunday into Monday. East-facing shore choppy wind waves will steadily increase through the latter half of the week in direct response to strengthening local and upstream trades. Surf along north-facing shores will remain very small in line with the season but some select exposures may catch some wind wave swell wrap. && .HFO WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 6 AM HST Thursday for Big Island Summits. Small Craft Advisory until 6 AM HST Friday for all Hawaiian waters. && $$ DISCUSSION...Birchard AVIATION...TS MARINE...Blood