Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
684 FXHW60 PHFO 070621 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 821 PM HST Thu Jun 6 2024 .SYNOPSIS... Light winds will continue through Friday with a ridge just north of Kauai. Over the weekend the ridge is expected to lift northward, allowing trade winds to gradually return and strengthen. Moderate to locally breezy trade wind conditions are expected by Sunday, and persist into the middle of the new week. Very stable conditions will greatly limit shower activity through the weekend, with a slight increase in windward showers expected Monday and Tuesday. A more typical trade wind pattern should return by the middle of next week. && .DISCUSSION... No significant changes to the forecast or forecast philosophy this evening. Anticipate making some changes to the PoPs and associated fields by the morning package for Tuesday onwards to reflect the latest guidance from the NBM. A relatively dry trade wind pattern is expected, through mid week, with a more typical trade wind pattern expected Thursday onwards. A east to west oriented ridge remains north of Kauai, maintaining light winds across the state. There is a roughly east to west oriented band of high clouds draped over the central islands that is moving south. Radar imagery and rain gage observations continue to show very dry conditions across the state. Expect clouds to clear overnight as land breezes develop. Chances of showers will remain very limited as the inversion heights remain between 3.5 and 4 kft, keeping any cloud development very shallow. A dry land/sea breeze pattern will hold through Friday as low inversion heights persist and the ridge of high pressure remains nearby. The ridge will begin to lift northward over the weekend, which will allow the trades to gradually return from south to north. Moderate to locally breezy conditions are expected by Sunday and persist into the middle of next week. Clouds and showers will return to the more typical windward and mauka areas, however shower activity will remain limited across the entire state over the weekend due to very stable conditions from low inversion levels. The trade wind inversion will begin to lift early next week, which should bring a slight increase in trade wind showers Monday and Tuesday, but will still remain drier than normal for this time of year. A more typical trade wind pattern should return during the middle to latter half of the week with rising inversion heights. && .AVIATION... Light winds will prevail across the state through Friday due to a weak pressure gradient across the region. As a result, daytime sea breezes and nighttime land breezes are expected to develop. Shower activity is expected to remain limited due to the presence of a relatively dry air mass. Conditions will remain mainly VFR, with brief MVFR possible through this evening. AIRMET Sierra is in effect for tempo mountain obscuration for windward sections of Oahu, Maui and the Big Island. Expect conditions to improve later this evening as land breezes develop. && .MARINE... The ridge to the north of the islands continues to slowly sink southward, weakening trade winds over the region. Expect wind speeds to remain below Small Craft Advisory (SCA) threshold through Friday. The ridge will lift northward over the weekend, allowing moderate trade winds to build back. Models show the potential for SCA conditions across typical windier waters around Maui County and the Big Island by Sunday. The current south-southwest swell has continued to fill in this afternoon and will peak Friday. Another, yet bigger moderate long period south- southwest swell will build into this weekend, peaking Sunday night into Monday which could reach High Surf Advisory level criteria of 10 feet at the peak of the event. A moderate long period south swell is expected to reach HSA levels late next week. The current small northwest swell continues to decline. However, a reinforcing pulse from the northwest will build in late Friday to give north facing shores a small bump. Wind waves for east facing shores have diminished significantly and will remain small into the weekend. && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...M Ballard AVIATION...Farris MARINE...Shigesato