FXHW60 PHFO 011840 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 840 AM HST Sun Mar 1 2026 .SYNOPSIS... Generally quiet weather through the forecast period as trade winds return tonight and continue through the weekend. && .SHORT TERM UPDATE... Issued at 837 AM HST Sun Mar 1 2026 Three foci of interest exist on the regional radar composite this morning. The first is a band of showers and isolated thunderstorms west of Kauai that exists along a corridor of weakly convergent SW flow that is perhaps slightly frontal in nature but it not particularly impressive overall. Nonetheless, it has shown an ability to capitalize on the weakly stable & moderately saturated mid-levels observed on this morning's soundings out of Lihue and Hilo in the presence of weak shortwave and right entrance jet support. Upper support rapidly fades this afternoon and deep layer flow above the boundary layer becomes more uniformly southwesterly causing convergence to be lost. This will leave the existing band of showers in a rapidly decaying state and ever-shallowing state as it encounters low-level trades that will likely halt eastward progress of its remnants. As such, expect any precip today to organize along corridors of convergence within island interiors with perhaps some overachieving showers given weak static stability noted on soundings and model cross-sections. The second focus of interest is a batch of showers presently located southwest of Kauai and Oahu and lifting toward the islands. This showers exist within a relatively deep pocket of moisture preceding the front, but appear largely driven by convergence in the lee of the islands as ESE flow wraps through the channels. The bulk of this activity will likely remain southwest of the islands, but a few showers may creep over the western islands during the day. Deep moisture suggests a few pockets of light stratiform may be in the offing as well. Sea breeze development will be hard to come by today given extensive high clouds, but if convergence can materialize over interior Kauai and Oahu, this pocket of moisture provide a boost to shower depth as it erodes existing stability. Finally, ESE flow has maintained a static area of shower regeneration along the Windward Coast of Oahu since yesterday. Low predictability of this feature exists due to its small scale, but given that the environment will undergo little change during the next 12 hours or so it is hard to argue against persistence. Will monitor this area for potential nuisance flooding, especially given observed rises that occurred on the Waikane Stream with this activity last night, but rain rates remain solidly below 1"/hr at this time. Trades return tonight. && .AVIATION... Issued at 837 AM HST Sun Mar 1 2026 A weakening cold front will slow in its approach over the western half of the island chain today, allowing for abundant high clouds and relatively light land/sea breezes to prevail across most TAF sites. This front will also allow for low-end rain chances across Kauai and Oahu this afternoon, however confidence was on the lower end based on weather model guidance, so made use of VCSH where rain chances were felt to be the highest. MVFR conditions may prevail under shower activity, otherwise VFR is expected across most sites for the period. AIRMET Sierra is in effect for mountain obscuration over SE Big Island, however this may need to be extended to other islands as this front continues to circulate more moisture into the area. AIRMET Tango is also in effect across the islands due to upper- level turbulence from FL200-400 due to this front as well, with conditions expected to improve into tomorrow as this front continues to weaken. && .DISCUSSION... The satellite imagery this morning shows a large band of high level jet stream cirrus clouds blanketing the islands. Expect cloudy skies from these high clouds to continue through Monday as a weakening cold front approaches the Hawaiian Islands from the west. The short range forecast guidance continues to show the forward motion with this front stalling out and dissipating near Kauai through Monday. Periods of enhanced showers are possible starting tonight over the western islands of Kauai and Niihau with some brief showers spreading as far east as Oahu and Molokai. Lighter winds will continue to produce sea breezes along terrain sheltered leeward slopes of each island. This period of light winds will begin to transition back to trade winds by Monday. These easterly trade winds will strengthen into the moderate to locally breezy range on Tuesday and Wednesday with brief passing windward and mountain showers, favoring the overnight to early morning hours. By Thursday, another weak cold front approaches the islands from the northwest direction, weakening the ridge north of the islands, and producing another round of east-southeasterly winds lingering into the weekend. Strong stable subsidence will keep shower activity to a minimum on Thursday. However by Friday an upper level disturbance over the region may increase shower activity as temperature inversion heights rise into the 7,000 to 8,000 foot range lasting through the weekend. && .MARINE... Moderate to locally fresh east to southeast winds will continue today as a weakening front stalls and diminishes near the western end of the state. This will allow localized land and sea breeze conditions to develop near sheltered coasts, particularly for the western end of the state closer to the trough. Fresh to locally strong easterly trades will return by Tuesday as surface ridge strengthens to the north, at which time Small Craft Advisories will likely be needed for the typically windy waters of Maui County and the Big Island. Surf along north and west-facing shores will continue to trend up slightly today as a fresh west-northwest swell arrives from a broad gale that was located south of the Aleutians near the Date Line. This swell will peak late today into Monday before gradually lowering by midweek. Surf along exposed east-facing shores will trend up slightly today as a fresh, short- to medium-period northeast swell from a gale centered around 1200 nautical miles northeast of the state arrives. Short-period and choppy conditions are expected to return by Tuesday as fresh trade winds redevelop and expand upstream of the state. Surf along south-facing shores will remain near the seasonal average into March. && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM UPDATE...JVC DISCUSSION...Bohlin AVIATION...Evans MARINE...Vaughan