Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
389 FXHW60 PHFO 020642 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 842 PM HST Mon Jul 1 2024 .SYNOPSIS... A broad high pressure ridge will remain locked in place north of the Hawaiian Islands into the upcoming weekend. Trade wind speeds will range from moderate to breezy for most days. Fairly stable conditions will produce mostly brief passing showers over windward and mountain areas. && .DISCUSSION... A broad subtropical ridge north of the island chain will keep moderate to breezy trade winds in the forecast lasting into the upcoming weekend. A slight ripple in the force is shown on infrared satellite imagery this evening as a band of clouds moves into the Big Island. This north to south oriented cloud band is associated with a weak low level trough riding into the islands on the easterly trade winds. Expect a slight increase in clouds and showers through the early morning hours across the windward slopes of Molokai, Maui and the Big Island as these unsettled clouds drift into the mountains of each island. Otherwise mostly dry conditions will prevail this week with only brief passing showers over windward and mountain areas. Shower amounts will be limited due to the strong subsidence under this high pressure ridge pattern. Trade wind thermal inversion heights will range from around 4,000 to 6,500 feet with most windward areas only seeing isolated to scattered shower coverage, favoring the overnight to early morning hours. Some exceptions may include the eastern slopes of Maui, and the windward and Kona slopes of the Big Island where periods of passing rain showers will likely continue. && .AVIATION... Moderate to locally breezy trade winds will continue through Tuesday. A band of low clouds and showers will bring some MVFR cigs/vsbys to windward areas as it moves from east to west across the state late tonight and Tuesday. No AIRMETs are in effect. AIRMET Sierra may be required for windward Big Island and Maui late tonight. && .MARINE... High pressure north northeast of the state will bring fresh to strong trade winds through most of the week. By this weekend, the high will weaken and move off to the northeast as a trough approaches from the west. This will allow for trades to ease slightly across the local waters. A Small Craft Advisory is posted for the waters and channels around the Maui and The Big Island through Wednesday morning, but will likely need to be extended through the remainder of the work week. No significant south swells are expected during the forecast period. However, a series of small south- southwest and southeast swells will keep south facing shores from going flat. Typical flat to tiny surf conditions will continue along north facing shores through most of the week. East shore surf will be close to seasonal levels over the next several days, as fresh to strong east northeast trades persist over and upstream of the islands. A fetch of strong northeast winds well off the California coast should bring a small northeast 3 to 4 foot medium period swell Saturday into early next week. Some of this swell should wrap into select north facing exposures as well. Water levels running roughly 0.5 ft higher than normal around the Big Island combined with the new moon tides could cause minor flooding issues between July 2nd and July 6th with peak water levels expected on July 4th. Our last full moon, we did receive reports of some areas of the coastline becoming inundated with the high tide such as Coconut Island and Puhi Bay. A Coastal Flood Statement will likely be needed for the Big Island near the 4th of July. For the other islands, water levels are running just a touch above normal and will likely not reach our criteria of 1 foot above the Mean Higher High Water (MHHW). && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 AM HST Wednesday for the windier waters around Maui and the Big Island. && $$ DISCUSSION...Bohlin AVIATION...Jelsema MARINE...JT