####018005191#### FXHW60 PHFO 030704 CCA AFDHFO Area Forecast Discussion...CORRECTED National Weather Service Honolulu HI 904 PM HST Thu May 2 2024 .SYNOPSIS... The high pressure center far north of the Hawaiian Islands will build through Friday producing breezy trade winds across the region. Breezy trade wind weather will last into the first half of next week. An upper level disturbance will enhance passing showers in the forecast into early next week, favoring windward and mountain areas in the overnight to early morning hours. A few of the stronger showers will drift into leeward areas. Long range guidance shows an old frontal band moving into the islands from the northeast next week Wednesday. This cloud band may bring another brief round of wet weather to all islands from Wednesday morning into next week Thursday. && .DISCUSSION... Satellite water vapor channel imagery this evening shows an unstable upper low spinning roughly 500 miles northwest of Kauai with an upper trough and subtropical jet stream over the Hawaiian Islands. This upper level disturbance will continue to enhance trade wind showers across the state into the first half of next week. Upper level cirrus clouds may enhance sunrise and sunset colors through Monday. The latest forecast guidance shows two high pressure systems in the Central Pacific consolidating into one high center. This high center is building slightly just north of the Hawaiian Islands on Friday. The strengthening high pressure ridge will increase trade winds into breezy levels from Friday into Monday. By Monday afternoon the high center drifts eastward away from the islands with a frontal trough moving into the Central Pacific basin. This change in large scale pressure patterns near the islands will decrease trade wind speeds back to more moderate levels from Tuesday onward. Expect continued enhanced showers across the state as the upper level disturbance slowly drifts eastward across the island chain. Most of the rainfall amounts will favor windward and mountain areas with decreasing shower activity over zones on the leeward sides of each island. These showers will tend to increase during our diurnal rainfall maximum in the overnight to early morning hours. In the extended forecast our long range guidance suggests a long band of unsettled clouds, remnants of an old cold front, drifts into the islands on the moderate trade winds from Wednesday morning into Thursday. This band produce wet weather over all islands for an 18 to 24 hour time period next week. The highest amounts will tend to favor windward areas, however many leeward sites may also see measurable rainfall totals with this system. && .AVIATION... Moderate to breezy E trades will continue to strengthen through Friday as high pressure builds in from the NE. A moisture plume riding the trades should bring in SHRA and MVFR conds to windward and mauka locations. While a few SHRA and lowering cigs/vsbys could reach leeward side, they look to be brief even with a slight increase in coverage. VFR conds will generally prevail. AIRMET Sierra is in effect for mtn obsc for windward and mauka portions of the island chain as an increase in SHRA and low cigs/vsbys increase for the overnight hours. AIRMET Tango is in effect for mod turb below 080 downwind of island terrain. AMD NOT SKED in for Midway due to missing wind speed and direction. && .MARINE... Moderate to locally strong easterly trade winds will gradually strengthen through Friday, becoming fresh to locally strong as high pressure builds and settles far north of the state. These stronger trades will continue through the weekend. A Small Craft Advisory (SCA) remains in effect for typical windy waters around Maui and the Big Island through early Monday morning. Additional waters will likely be added to the SCA in the next package as trade winds continue to strengthen and expand in coverage across additional coastal zones. Tiny surf will persist along north and west facing shores through much of the day on Friday. A small, long period northwest swell is expected to fill in late Friday and peak Saturday, bringing small surf along north and west facing shores. Another small, long period northwest swell will fill in late Sunday, maintaining small surf along north and west facing shores into early next week. Small background south swells will continue into Saturday, providing tiny surf for south facing shores. A small, long period south swell may arrive Sunday providing a boost in surf along south facing shores into early next week. Surf along east facing shores will gradually become more rough and choppy into this weekend as stronger trades return. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 AM HST Monday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...Bohlin AVIATION...SMW MARINE...Almanza