Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
546 FXHW60 PHFO 231901 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 901 AM HST Thu May 23 2024 .SYNOPSIS... Moderate to breezy easterly trade winds will linger over the islands into the weekend. Clouds and showers will favor typical windward and mauka areas during this time. && .DISCUSSION... Locally breezy trades are focusing limited clouds and showers windward and mauka at press time. This is courtesy of S to SE flow above 850mb steering the lion`s share of moisture northwestward and parallel to the island chain. This layer of winds will turn more onshore in time, but will advect drier air into the region as it does so leading to a continued modest coverage of windward showers. This will particularly be the case over the eastern end of the state where dry advection will be most pronounced. The gradient then weakens during the weekend as upper-level troughing digs southward Saturday and Sunday befoModerate to breezy easterly trade winds will persist across the Hawaiian Islands today and tomorrow. Isolated to scattered showers today will favor the windward coasts and slopes through the period, with greater coverage expected during the overnight hours. Brief MVFR conditions are possible in moderate showers. AIRMET Sierra for mountain obscuration is in effect for windward areas of Kauai, Oahu, Maui and the Big Island, and for all of Lanai. Low cloud ceilings should decrease in coverage later this morning leading to cancelling this AIRMET for most of the affected areas.re advancing eastward across the forecast area early next week. The gradient will diminish during this time as winds veer to ESE leading to an expansion in sea breeze coverage in the more sheltered locales. This will be accompanied by the typical increase in afternoon clouds along with a few showers. Model consensus points toward an amplifying upper-level trough becoming established over the forecast area during the second half of next week. This will cause further weakening the local gradient and an expansion of the land and sea breeze pattern to encompass most areas. && .AVIATION... Moderate to breezy easterly trade winds will persist across the Hawaiian Islands today and tomorrow. Isolated to scattered showers today will favor the windward coasts and slopes through the period, with greater coverage expected during the overnight hours. Brief MVFR conditions are possible in moderate showers. Otherwise, VFR conditions will prevail. AIRMET Sierra for mountain obscuration is in effect for windward areas of Kauai, Oahu, Maui and the Big Island, and for all of Lanai. Low cloud ceilings should decrease in coverage later this morning leading to cancelling this AIRMET for most of the affected areas. && .MARINE... High pressure will gradually build westward well to the north of the state through Friday, strengthening the trade winds into the fresh to strong range across the island chain. A Small Craft Advisory (SCA) is in effect for most waters around Maui and the Big Island through 6 AM Friday, and for the windier zones in that area through 6 PM Saturday. A trough of low pressure amplifying and lingering west of the islands this weekend may cause the trades to ease a bit and shift to a more east-southeasterly direction over the western end of the state. Moderate to strong easterly trades will prevail over the eastern waters. South shore surf will remain small and below the summer average through the middle of next week, with only small and inconsistent pulses of southwest swell expected. The next significant south- southwest swell (200 deg) appears to move in toward the end of next week. East shore surf will remain near the seasonal average through Friday, followed by a slight decrease 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-Big Island Windward Waters. Small Craft Advisory until 6 PM HST Saturday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...Ahue/JVC AVIATION...Farris MARINE...TS