Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
284 FXHW60 PHFO 161333 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 333 AM HST Mon Jun 16 2025 .SYNOPSIS... Fairly stable and breezy trade winds will start the week as a broad high pressure ridge remains in place far north of the island chain. Trade wind speeds will decrease slightly to more moderate levels from Tuesday through Friday, breezy trade winds return by the weekend. A few showers are possible in this pattern especially along the windward and mountain slopes, favoring the overnight to early morning hours. && .DISCUSSION... This mornings satellite imagery shows a few bands of unsettled clouds riding into the windward slopes of each island on the easterly trade winds. These brief passing shower trends will diminish later this morning. Upper air weather balloon soundings, from 2 AM HST (12Z) at Lihue and Hilo, show temperature inversion heights around 5,000 feet and 6,000 feet respectively. These low inversion heights will reduce vertical cloud development and limit shower coverage. A few high level cirrus clouds will pass over the islands today produced by a weak upper low centered just west of Kauai. The high pressure ridge far north of the Hawaiian Islands will remain in place through the week. A passing low pressure system moving through the Central Pacific basin will weaken the strength of this ridge slightly from Tuesday onward. Wind speed trends will decrease slightly into the more moderate levels through Friday. The ridge will then build back into the region by this weekend with a return to more breezy easterly trade winds. Fairly stable conditions remain in the forecast for the next seven days. Low temperature inversion heights in the 5,000 to 7,000 foot range will limit most of the shower activity to windward and mountain areas in the overnight to early morning hours. A few ripples in the buoyancy force show up in the forecast guidance that may produce a few variations in this stable theme, leading to brief increases to local shower activity at times over some island regions. However, rainfall amounts will remain on the low side in this stable high pressure ridge pattern. && .AVIATION... Breezy trade winds with mostly stable conditions expected to last into Tuesday. Wind speeds will decrease to more moderate levels from Tuesday onward. Shower activity will be limited to windward and mountain airfields, favoring the overnight to early morning hours. AIRMET Tango remains in effect for moderate turbulence over and south through west of island mountains. && .MARINE... A high pressure north of the state will drive trades through the week. A slight weakening trend in the winds is expected as the high moves eastward. A Small Craft Advisory (SCA) for the windier waters and channels near Maui and the Big Island goes through 6AM Wednesday with a likely extension. A series of small, long-period, south swells will help boost surf heights along south facing shores though the week. The current south swell will decline over the next couple days followed by another south swell from Wednesday into Thursday. Rough and choppy surf along east facing shores will continue this week. Surf will remain nearly flat along north facing shores throughout the forecast period. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 AM HST Wednesday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...Bohlin AVIATION...Bohlin MARINE...Walsh