208 FXHW60 PHFO 021751 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 751 AM HST Mon Jun 2 2025 .UPDATE... Aside from windward areas of the Big Island, morning rain chances were lowered slightly for the eastern half of the island chain due to trends noted on radar. && .SYNOPSIS... The combination of surface high pressure far northeast of the islands and a deep surface trough to the west of Kauai will maintain east-southeast winds and a somewhat active shower pattern around Kauai and Oahu today, while a more typical trade wind weather pattern with periods of high clouds persists over Maui County and the Big Island. Locally breezy trades will return to the entire state on Tuesday, focusing showers over windward slopes. A decrease in winds is expected for the weekend. && .PREV DISCUSSION.../ISSUED 422 AM HST Mon Jun 2 2025/Early morning shortwave infrared satellite and radar imagery continue to show the dominant east southeast steering flow in the lower level cloud field and the widely scattered shower activity, respectively. The slightly veered southeast wind profile is a result of a broad upper trough and weak surface reflection located just west northwest of Hawaii. A dense cirrus deck shrouds the majority of the island chain as southwesterly moisture rides up ahead of this broad troughing. A dominant ridge centered far north northeast of the region is still the main driver to this generally east trade wind pattern. Energy diving south into the west trough creating more efficient upper divergence downstream of the near meridional trough axis, will maintain higher rain chances over Kauai and surrounding waters. Light to locally breezy east to southeasterly low level flow pattern is expected to continue through the day. Clouds and showers will favor windward and mauka areas during the overnight to early morning hours...sea breezes developing over leeward and interior areas during the afternoon hours will increase daytime showers over these communities. This flow may also create low level convergent boundaries, or plumes, that will form downstream of each island. These plumes could be the catalyst to higher rainfall across neighboring downstream islands due to more parallel flow along the island chain. Enhanced shower activity may occur across the western end of the state into the late afternoon hours due to higher instability aloft and low level moisture upper troughing digs further southward west of Kauai. A return to breezy and more stable trade wind weather is expected tonight as upper riding expanding in from the northeast increases heights in tandem with drier mid layer air advecting in from the east. A easterly trade wind pattern will hold through the middle of the week with showers favoring windward and mauka areas... primarily dry conditions will prevail elsewhere. For the latter part of the week, trades will slightly ease as weak upper level troughing moves overhead and another broad surface trough develops west of the state. However, the instability associated with the trough aloft and the available moisture look rather meager. Thus, not much more than perhaps a slight enhancement of trade wind showers is forecast for the end of the forecast period. Vog will continue to filter across the island chain trapped within easterly flow, transitioning west and further south of the smaller islands by tomorrow as the trades return. && .AVIATION... Moderate to locally breezy east-southeasterly winds should persist through the rest of today and late tonight move back to a more typical trade wind pattern. Troughing to the west of the islands has significantly increased high clouds which has also supported occasional SHRA as moisture embedded within the ESE flow moves over the islands. Low cigs and SHRA have on occasion produced IFR/MVFR conds. VFR prevails outside of any heavier SHRA. AIRMET Sierra remains in effect for mtn obsc over Kauai and Oahu. It is also in effect for windward Big Island. AIRMET Tango is in effect for mod low-level turb blw 080 downwind of island terrain. It is also in effect for mod turb abv FL250. && .MARINE... Fresh east southeast winds will occur today in response to an upper low and associated surface trough west of Hawaii. The trough will move westward and allow surface ridging to expand down from the north. This will result in trade winds backing to a more easterly direction through the day. A Small Craft Advisory (SCA) is in effect for winds over the typical windy waters in addition to the windward Maui waters through tonight. The SCA will be in effect for the typically windy waters surrounding Maui and Big Island through Tuesday night. The late season northwest swell will continue its decline through the day with north and west-facing shore surf dropping to near June averages by Tuesday. Surf along south-facing shores will continue to see a mix of small background swell the next few days, followed by small southwest swells late Tuesday and Wednesday. A larger, longer period south southwest swell will build in Friday and peak over the weekend. This should produce above seasonal average surf along many southern beaches. East-facing shore surf will gradually build to near or above seasonal averages through Wednesday due to fresh to locally strong trades over and upstream of the islands. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 AM HST Tuesday for Maui County Windward Waters-Big Island Windward Waters. Small Craft Advisory until 6 AM HST Wednesday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ UPDATE...Wroe DISCUSSION...Blood AVIATION...Walsh MARINE...Blood