Last Updated on Wednesday, 27 August 2014 07:43
Winds Statewide in a glance ...go HERE (this link is also the 4th drop down under weather)
Aug 27, 2014 3:35 AM HST
Trade showers continue this morning with rainfall focusing over windward and mountain areas. The trades will gradually weaken Thursday through Saturday and allow for sea breezes to develop each day. This will bring periods of clouds and showers over leeward and interior areas through the weekend. Then the trades will strengthen again early next week with showers focusing back over windward and mountain areas.
Water vapor satellite imagery show an upper lvl low about 580 miles WNW of Kauai. The circulation on the E side of this low is pulling some of the scattered layered/high clouds near the ITCZ into the islands. Meanwhile, sfc high pressure remains centered far NNE of the aloha state and keeping a moderate trade wind regime across the island chain today.
At 3 am HST, radar data was showing showers just e/ne of the islands, bringing periods of rain over most windward and mountain areas, which will continue through the mid morning hours today. 12Z sounding data and mimic moisture analyses show pwats in general of 1.20 to 1.45 inches around the main Hawaiian islands, and a dryer airmass further upstream. Therefore, expect trade showers to continue this morning with rainfall focusing over windward areas, the Koolau range in Oahu, the W Maui mountains and windward Haleakala.
A brief drying trend will take place later today and tonight as the aforementioned drier airmass moves into the area. Then for the second half of the week, despite the arrival of the drier airmass, the global models show fair agreement regarding the passage of the remnants of former tropical cyclone Lowell far NW of the islands. This will temporarily weaken the trade wind flow and allow for sea/land breeze circulations to develop each afternoon Thu through Sat. Expect possible periods of afternoon and early evening showers, especially over interior and leeward areas.
For the long range forecast, the sfc high strengthens NNE of the aloha state with the trades gradually return to moderate lvls Sun into Mon. This will bring back a trade wind weather regime early next week with showers favoring windward and mountain areas, especially at night.
An increasing easterly long-period swell from hurricane Marie is expected to begin arriving later today and continue to build through Thursday night. This swell will bring advisory level surf to east facing shores by Thursday. Also, an increasing south-southwest swell is anticipated for tonight and into Thursday, bringing near advisory level surf over south facing shores through Friday. Strong currents could also develop with the arrival of these swells. The surf should begin subsiding Saturday and continue to decline through early next week.
With winds expected to diminish further, no small craft advisory conditions are expected through the holiday weekend. However, the long period easterly swell mentioned above could produce unusual conditions in east facing channels and harbors.