Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
082 FXHW60 PHFO 261953 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 953 AM HST Wed Jun 26 2024 .SYNOPSIS... A stable trade wind pattern will persist through Thursday with breezy to locally windy trades. Periodic light showers will focus over windward and mauka areas during this time. An increase in shower activity and isolated thunderstorms will be possible over portions of the state from Friday into the weekend as an upper- level disturbance approaches and moves over the region. && .DISCUSSION... Breezy to locally strong easterly trade winds continue to prevail across the islands today, steered by high pressure that remains centered approximately 850 miles north of Kauai. Clouds and a few light showers embedded within the trades are favoring windward and mauka areas, though rain gauges statewide show that accumulations have been very light this morning. For the rest of the day, expect this pattern to continue with breezy to locally windy trades and light showers favoring windward and mountain locations. Winds will remain breezy to locally windy through Thursday as the high pressure to the north remains in place. Impulses of moisture embedded in the trade wind flow will continue to favor windward and mauka areas, though rainfall accumulation will be limited. Aside from some brief afternoon and evening showers over Kona slopes of the Big Island, leeward areas will remain mostly dry. Guidance continues to show an upper-level disturbance moving near the islands Friday and then over the western end of the state this weekend. This disturbance will destabilize the atmosphere and enhance our trade wind showers, particularly on Saturday night. Isolated thunderstorms continue to be a possibility over the slopes of the Big Island on Friday and Saturday afternoons and over the western end of the state on Saturday and Sunday as temperatures aloft cool. However, with precipitable water forecast to be near seasonal normals, moisture availability will be a limiting factor. Will continue to evaluate thunder chances over the next several model runs, with further adjustments of timing and areal coverage expected. Otherwise, enhanced trade wind showers look to continue into Monday. Conditions return to a more typical summertime trade wind pattern by early next week. && .AVIATION... Breezy trade winds will persist across the island chain through Thursday. Showers and low clouds riding in on the trades will bring brief periods of MVFR conditions over windward and mauka locations. Otherwise, VFR conditions will prevail. AIRMET Tango remains in effect for moderate low-level turbulence over and downwind of island terrain due to breezy trade winds under the tradewind inversion. No other AIRMETs are in effect at this time. However, AIRMET Sierra for tempo mountain obscuration may be needed again tonight if shower coverage increases. && .MARINE... High pressure will continue to dominate the Central North Pacific, but is expected to weaken slightly and shift eastward for the weekend. Moderate to locally strong easterly trades will persist through Thursday then weaken slightly to the gentle to fresh range beginning on Friday and hold through the weekend. A Small Craft Advisory (SCA) for the typically windier waters around Maui County and the Big Island remains in effect. The SCA may be dropped as early as Thursday Night, but conditions could linger through Friday. An upper level low will bring the potential for unsettled weather to the Islands on Saturday and Sunday. Isolated thunderstorms are possible, especially over the western half of the state, and should be assumed to trigger locally higher winds and seas. For the coming week, high pressure to the Northeast of the state is expected to hold while a new stronger high builds to the northwest. SCA conditions are likely to return to the Pailolo and Alenuihaha Channels as early as Sunday afternoon. Meanwhile, surf along east-facing shores will gradually ease as the weekend approaches as the winds locally and upstream both trend downwards. Along south facing shores, a small, medium- to long- period south swell will fill in tonight, before peaking Thursday night then gradually ease into the weekend. Near to below average surf along south facing shores is expected into the coming week as well. A small, medium period, northwest swell is expected to fill in tonight and peaking Thursday night, thus providing a small bump along north facing shores that will persist through Friday then virtually disappear over the weekend. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 PM HST Thursday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...Vaughan AVIATION...TS MARINE...Birchard/Bedal