textproduct: Honolulu

SYNOPSIS

An upper level ridge will move in and bring a return to cooler and drier trades through Thursday. Winds will veer to southeast Friday and remain that way into the weekend, bringing warmer temperatures and a sea- and land-breeze pattern. Sunday night into early next week has the potential for another boundary to move through with some wet weather. Moderate to breezy trade winds will blow across the region with decreasing shower trends as high pressure builds in through Thursday. Winds begin to weaken and veer more southeasterly from Friday into the weekend ahead of the next cold front approaching the islands from the west.

DISCUSSION

As of 3am radars show scattered showers moving across the island chain. Mostly along windward and mauka locations. Breezy trade winds are ongoing and are expected to remain over the area through Thursday. This will bring additional showers over the next few days, mainly windward and mauka.

An upper level ridge will finally replace the trough that has brought significant rains to the area in recent days. Today through Thursday we will see a typical trade wind pattern. Drier and cooler air will be advected into the region. This will allow for cool mornings in areas sheltered from the trades.

As the upper level ridge axis moves east of the state Thursday night into Friday, our low level flow will veer and become more southeasterly. This will begin to slowly increase low-level moisture. As wind speeds weaken, sea- and land-breezes will develop this coming weekend. This pattern typically results in showers forming both windward and leeward. Long range models show the potential for a boundary to bring an increase in showers Sunday night into Monday of next week.

AVIATION

Windward showers continue for the Big Island, while gradual clearing takes place across the rest of the island chain. Isolated windward showers may occur across the rest of the islands during the day today, however confidence was low so only made mention of VCSH across these sites. Otherwise, NE winds will continue to trend downward through the period.

AIRMET Sierra remains in effect for windward Maui and the Big Island.

MARINE

Strong high pressure remains far north of the state, while a weakening surface trough lingers in the far southeast offshore waters. Northeasterly trade winds look to strengthen to fresh to strong speeds through tonight before gradually easing to locally strong speeds over just the windier waters and channels around Maui County and the Big Island Wednesday and Thursday. A Small Craft Advisory (SCA) has been expanded to all coastal waters and extended through tonight due to a combination of winds and mainly seas above SCA criteria due to the large north northeast swell currently impacting the islands. An approaching front will likely cause winds to decline and veer out of the southeast Thursday night into Saturday.

A large, long period north-northeast (010-030 deg) swell has peaked early this morning and will look to hold through the morning hours before declining through the end of the week. This swell will produce breaking waves at High Surf Warning levels across most north and east facing shores through this afternoon. Due to the direction of the large swell, exposed west facing shores of West Maui, western Molokai, and North Kohala on the Big Island will likely experience High Surf Advisory conditions. The north- northeast swell will gradually decline tonight at High Surf Advisory (HSA) level conditions through Wednesday before continuing to decline through Friday. In addition to this swell, a small pulse of overlapping west- northwest swell is expected through Wednesday.

Due to the direction of the large north-northeast (010-030) swell, some overwash will be possible along low-lying coastal roads and infrastructure in windward areas, especially in the Keaukaha area east of Hilo. Hazardous conditions and heavy surges are expected in north facing harbors, mainly in Hilo and Kahului, and a Marine Weather Statement remains in place to highlight this threat.

South facing shores will remain tiny today due to a small background southwest swell before flat wintertime surf will continue along south facing shores through the end of the week week.

HFO WATCHES/WARNINGS/ADVISORIES

High Surf Warning until 6 PM HST this evening for Niihau-Oahu North Shore-Olomana-Maui Windward West-Kauai North-Kauai East- Koolau Windward-Molokai Windward-Molokai North-Maui Central Valley North-Windward Haleakala-Big Island East-Big Island North.

High Surf Advisory until 6 PM HST this evening for Maui Leeward West-Kohala-Molokai West-Lanai Windward.

Small Craft Advisory until 6 AM HST Wednesday for all Hawaiian waters-