Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
152 FXHW60 PHFO 172003 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 1003 AM HST Mon Jun 17 2024 .SYNOPSIS... A high pressure ridge north of the state will maintain breezy trade winds through Tuesday with trades strengthening Wednesday onward. Breezy to strong trade winds are expected Wednesday through the weekend. A weak upper low over the state will help produce periods of showers mainly over the windward and mountain areas through Tuesday. Drier conditions are briefly expected Wednesday with scattered showers returning Thursday. Remnants of an old frontal boundary will likely increase shower activity late Friday into Saturday. && .DISCUSSION... A weak upper level low over the state has raised the inversion heights slightly and the 12Z soundings from Lihue and Hilo show the trade wind inversion just over 7000 ft. With the slightly higher inversion, we are seeing a little more showers across the state this morning, but shower intensity remains on the light side for the most part. For the rest of today and through Tuesday, we should be in a fairly similar weather pattern with breezy trade winds and passing showers. Showery activity will be slightly higher than our typical summer day due to the upper level low, with some moderate showers possible over windward areas. As the upper level low gradually moves westward over the next few days, we should see drier conditions with lower inversions on Wednesday. Starting Wednesday into Thursday, the high centered far north of the state will strengthen and will increase the trade wind speeds. Breezy to strong trades are expected during the second half of the week and it may even strengthen a little more this weekend. Overall a windy weekend is expected and it could reach wind advisory threshold for select areas, especially the windier zones around Maui County and the Big Island. On Friday, models are showing moisture associated with an old frontal boundary riding in with the trade winds, which could produce showery weather especially across select windward areas late Friday into Saturday. && .AVIATION... Breezy easterly trades will continue, with clouds and showers favoring windward and mauka locations. Periods of MVFR conditions will impact these windward sections mainly during the overnight to early morning hours. Otherwise, VFR conditions will prevail. AIRMET Sierra for tempo mountain obscuration is in effect for most windward areas. Conditions should improve later this morning. If winds increase under the strong tradewind inversion today, AIRMET Tango for low level turbulence lee of the island terrain may be needed. && .MARINE... A high pressure ridge will remain north of the area and will gradually strengthen during the second half of the week. Moderate to locally strong trade winds are expected through Tuesday as a Small Craft Advisory (SCA) is currently in effect for the typical windier waters around Maui County and the Big Island. Trade winds look to strengthen across all waters as the SCA is likely to be expanded to add the waters around Kauai and Oahu on Wednesday through potentially the end of the week. The current south swell will continue to slowly fade. For the rest of the week, expect only background small, medium to long period, south to southeast swell energy moving through the local waters. Weak lows continue to sweep across the northwest Pacific as north facing shores will remain tiny to small with background energy through the week. Surf along east shores will become increasingly rough and choppy from Wednesday onward as the trade winds strengthen across the state. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 PM HST Tuesday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...Kino AVIATION...Farris MARINE...Shigesato