Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
682 FXHW60 PHFO 251949 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 949 AM HST Sat May 25 2024 .SYNOPSIS... Broad high pressure north and northeast of the state will maintain moderate to locally breezy easterly trade winds through the week. Showers will mainly favor windward slopes, and batches of high clouds will pass overhead at times. && .DISCUSSION... Moderate to locally breezy easterly trade winds remain in place. The trades are being driven by broad surface high pressure sitting roughly 1400 miles north of the state, and a surface trough parked about 600 miles west of Kauai is causing the winds to be more easterly than usual, especially over the western end of the island chain. Mid-level ridging over the islands is maintaining somewhat stable conditions, and shallow moisture moving along the trade wind flow will focus modest rainfall of around a quarter of an inch per day across most windward slopes. An upper-level trough generally collocated with the surface trough is producing thunderstorms about 200 miles west of Kauai, and westerly winds aloft are carrying thin high clouds over the state. Thunderstorm activity will remain west of the state through the holiday weekend, but the inversion will could be weakened at times near Kauai, where brief periods of enhanced showers will be possible. In addition, expect spotty afternoon and evening showers, some briefly heavy, across leeward Big Island. Little change is expected Tuesday onward. The surface high will settle far northeast of the state and hold into Friday, and the surface trough will linger west of the islands, resulting in breezy easterly trade winds. The nearby upper-level trough will weaken, suggesting grater stability and supporting a typical rainfall pattern with showers continuing to favor windward slopes. && .AVIATION... Moderate to locally breezy trade winds will prevail across the Hawaiian Islands for the next several days. As a result, AIRMET Tango remains in effect for moderate low-level turbulence downwind of island terrain. This AIRMET will likely remain in effect though much of next week. A fairly stable pattern will remain over the state into next week. However, passing showers will favor north through southeast sections of the islands, with greater coverage expected during the overnight hours each night. While VFR conditions will prevail over most locations, brief MVFR ceilings and visibilities will be possible as showers move through. && .MARINE... High pressure north of the state will maintain moderate to locally strong easterly trade winds across the state through the first half of next week. A Small Craft Advisory (SCA) remains in effect for the windiest waters around Maui and the Big Island through 6AM Sunday. A trough will amplify and linger west of the islands Sunday through the middle of next week, resulting in a shift to a more east-southeast direction over the western end of the state. This will allow the trades to ease slightly over the leeward waters of Kauai and Oahu. Moderate to locally strong easterly trades will continue to prevail elsewhere across the state. South shore surf will remain small and below the summer average through the middle of next week, with only small pulses from the southeast and southwest. The next significant south-southwest swell (200 degrees) appears to move in toward the end of next week. East shore surf will decrease slightly this weekend then hold steady through late next week. 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 Sunday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...Wroe AVIATION...Vaughan MARINE...Kino