Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
690 FXHW60 PHFO 230622 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 822 PM HST Wed May 22 2024 .SYNOPSIS... Moderate to breezy easterly trade winds will spread over the state tonight into Thursday and linger through the first half of next week. Clouds and showers will favor typical windward and mauka areas. && .DISCUSSION... The latest surface analysis shows a trough of low pressure around 500 miles west of Kauai, with a 1036 mb high centered 1400 miles north-northeast of Honolulu. Satellite and radar imagery shows clouds and showers over mainly windward and mauka areas this evening as clouds that developed over leeward areas of the western islands this afternoon continue to dissipate. Expect moderate to locally breezy easterly trades to continue over the eastern islands tonight, with moderate east-southeast winds over Oahu and Kauai becoming more easterly overnight. Otherwise, there has been little change to the overall forecast. Moderate to breezy easterly trades will spread across the state Thursday as high pressure continues to slowly shift north of the state. A series of reinforcing highs will build to our north through the first half of next week maintaining moderate to breezy easterly trade winds. Guidance continues to show drier air filtering into the region over the next couple of days with dew points returning to near normal by Friday. Weak upper level troughing will give way to ridging allowing for a more dry and stable trade wind pattern to develop through the weekend. Expect windward and mauka showers to increase in intensity and coverage during the overnight and early morning hours, with a few of these showers briefly spilling over into leeward areas. This pattern should hold through the first half of next week. && .AVIATION... Moderate to locally breezy easterly trade winds will blow over the eastern half of the Hawaiian Islands with moderate east to southeast winds over the western half of the state through the night. Easterly trade winds will spread to all island by Thursday morning. Expect scattered to numerous showers over the windward and mountain areas with isolated showers over leeward areas through the overnight hours. Brief MVFR conditions are possible in moderate showers. Isolated to scattered showers on Thursday will favor the windward slopes. AIRMET Sierra for mountain obscuration remains in effect for windward areas of Oahu, Maui and the Big Island. Satellite imagery continues to show some more moisture upstream, so this AIRMET may be needed through tonight. && .MARINE... High pressure will gradually build westward well to the north of the state tonight through Friday, strengthening the trade winds across the island chain. Fresh to strong trade winds over the eastern end of the state will expand westward over the Oahu and Kauai waters on Thursday and hold at those levels through Friday. A Small Craft Advisory remains in effect for most waters around Maui and the Big Island through 6 AM Friday, and this will likely be extended in time and possibly expanded in coverage with the morning forecast package. A trough of low pressure will amplify to the west of the islands this weekend and linger into early next week. This will ease the trades and shift them around to a more east-southeasterly direction over the western end of the state, while moderate to strong easterly trades prevail over the eastern waters. The current south swell will continue to decline tonight. South shore surf will remain small and below the summertime average through the middle of next week, with only small inconsistent pulses of southwest swell expected. The next significant south- southwest swell appears to move in late next week. East shore surf will remain near the seasonal average through Friday. A slight decrease is expected this weekend through the middle of next week as the trades ease over and upstream of the islands. Surf along north shores will remain very small with a slight bump possible late Sunday through Monday. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 AM HST Friday for Maui County Windward Waters-Pailolo Channel-Alenuihaha Channel-Big Island Windward Waters-Big Island Leeward Waters-Big Island Southeast Waters. Small Craft Advisory from 6 AM Thursday to 6 AM HST Friday for Maalaea Bay. && $$ DISCUSSION...Ahue AVIATION...Bohlin MARINE...Jelsema