Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
429 FXHW60 PHFO 050702 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 902 PM HST Sat May 4 2024 .SYNOPSIS... Breezy trade winds will continue into Monday and then decrease to more moderate levels from Monday afternoon into Tuesday. An upper level disturbance passing through the islands will keep enhanced showers in the forecast through Monday. An unstable band of clouds and showers will drift into the islands on the trade winds, bringing another round of wet weather for all islands from Wednesday into Thursday. && .DISCUSSION... The satellite water vapor imagery this evening shows a weakening upper level low roughly 600 miles west of Kauai. This low will continue to weaken as it slowly drifts eastward across the Hawaiian Islands over the next two days. A subtropical jet stream is also set up over the islands. Stronger winds aloft may produce Wind Advisory conditions over the highest summits of Mauna Kea and Mauna Loa by Sunday. Otherwise the presence of high level cirrus clouds may enhance sunrise and sunset colors across the state. A 1030 mb high pressure system far north of the island chain will continue to produce breezy easterly trade winds across the state into Monday. By Monday afternoon the high pressure system drifts eastward, trade wind speeds will transition to more moderate levels by Monday afternoon as this system moves away from Hawaii. Expect moderate easterly trade winds to continue through the rest of the week. Enhanced showers will continue into Monday as a weakening upper level disturbance drifts from west to east across the island chain. Tuesday will trend a bit drier. An unstable band of clouds and showers, remnants of an old East Pacific cold front, will drift into the islands on the trade winds producing wet weather for all islands from Wednesday into Thursday. An upper level trough sweeping in from north on Thursday and Friday will likely keep enhanced showers in the forecast through the rest of the week. && .AVIATION... Breezy easterly trade winds will persist through the weekend, with clouds and showers continuing to favor windward and mauka locations. MVFR conditions will be possible in showers, especially across windward areas overnight through the early morning hours. Elsewhere, a few showers may occasionally make it over to leeward sections, but VFR conditions will generally prevail. AIRMET Sierra could be needed later tonight for tempo mountain obscuration over windward portions of each island. AIRMET Tango is in effect for mod turb below 9000 feet downwind of island terrain. Additionally, some moderate turbulence aloft (FL280-FL350) is expected through tomorrow. && .MARINE... Consolidating high pressure far north of the islands will support fresh to strong easterly trade winds into Monday, with the typical windier waters around Maui County and the Big Island approaching near- gale force speeds. A Small Craft Advisory (SCA) for all waters will remain posted through at least Sunday night. The high will move east thereafter, leading to a gradual easing to moderate to locally strong speeds by the middle of next week. The SCA may be pulled back over the first half of the week to the typical windier waters around Maui County and the Big Island by Tuesday. A disturbance aloft will allow for the development of a few heavier showers the next couple of days, producing periods of gusty winds and reduced visibility. Combined seas increased to near 10 feet at several of the near- shore PacIOOS buoys due to an increase in short-period wind waves. East facing shores will continue to see rough and choppy seas for at least the next several days. North facing shores will remain elevated as a small to moderate medium period swell fills in tonight before slowly easing Sunday and into Monday. A reinforcing slightly smaller northwest swell will move in Monday before fading into midweek. South facing shores will continue to see consistent pulses of swell through next week as storm activity in the South Pacific ramps up. The first of these hit the Lanai buoy this afternoon with 22 second energy and will build tonight into Sunday, with peak surf heights remaining below High Surf Advisory (HSA) heights. Reinforcing south to southwest swells arriving Sunday and Monday may be large enough to warrant a HSA. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 AM HST Monday for all Hawaiian waters && $$ DISCUSSION...Bohlin AVIATION...Gibbs MARINE...Shigesato