Glenn’s Daily Weather Narrative

Broad Brush Overview: The next cold front approaching the state will continue to weaken the high pressure ridge over the state, keeping variable sea breezes over most islands. The position of the ridge remains directly over the islands keeping fairly stable conditions in place.

Light large scale east to southeasterly winds will allow local scale sea breezes to build clouds and produce a few showers over island mountain and interior sections. Trade winds will return Friday as high pressure strengthens behind a dissipating cold front.

Cloud and shower bands associated with the frontal remnants will drift over the islands, from northwest to southeast Friday and Saturday. A low level trough may pass through the region next Tuesday…boosting trade wind shower activity through mid-week.

Weather Details: Satellite imagery shows a cold front approaching the islands from the northwest and a series of upper level lows far northeast to east of the state. A weak low level trough is drifting into the eastern half of the state, with slight increases to clouds over south and east Big Island, and east Maui.

This cold front will continue to weaken the high pressure ridge over the state through Friday. The position of the ridge directly over the islands will keep fairly stable conditions in the forecast for most locations. Light east to southeasterly winds will allow local scale land and sea breezes to continue.

Converging sea breeze winds and surface heating will build clouds over island interior sections, with a few showers possible as convergent winds and surface heating decreases, causing larger cumulus clouds to collapse and cloud droplets to fall as rain.

The cold front will dissipate by Friday as it approaches the island chain. Remnant cloud bands and showers will drift into Kauai and Oahu by Friday night, with increasing shower coverage reaching Maui and Hawaii Counties on Saturday.

A high will build in behind the front Friday, allowing trade winds to return. An upper level low will pass just east of the Big Island Monday. Expect stronger upper level northerly winds affecting the mountain peaks of Haleakala on Maui, Mauna Kea and Mauna Loa on the Big Island…as this upper low passes just east.

This upper low appears to form a low level trough, moving towards the islands on the trade wind flow. This trough will move into the state on Tuesday and Wednesday, and in turn likely enhancing trade wind clouds and showers…favoring northeast windward slopes.

>>> Here’s a near real-time Wind Profile of the Pacific Ocean – along with a Closer View of the islands / Here’s the latest Weather Map.  Here’s the animated volcanic emissions graphic

Marine Environmental Conditions: A surface ridge of high pressure over the area will continue to support light to locally moderate winds into tonight, favoring an east to southeast direction near the Big Island, and southeast to south near Kauai.

A weakening cold front moving toward the area will cause the ridge to move south and weaken, resulting in a brief period of light and variable winds tonight into Friday. A high pressure cell passing north of the area will then support moderate to locally strong northeast winds Friday afternoon into early next week.

These stronger winds could potentially reach Small Craft Advisory (SCA) levels over the typically windy waters around Maui County and the Big Island. The passing high will also push fragments of the front over the area, leading to an increase in showers, mainly over windward waters Friday and Saturday.

There will be a temporary lull in the surf along the north and west shores, before a powerful west-northwest swell builds Friday, peaks Friday night and Saturday, then lowers Sunday and Monday. A High Surf Warning (HSW) will likely be necessary for exposed north and west shores, including the west  shores of the Big Island.

After dropping below HSW level, continued wave energy from the west-northwest may require a high surf advisory through early next week. The weekend’s large swell will require a SCA for seas in most marine areas. Additionally, a small to moderate east-northeast swell is possible over the weekend.

World-wide Tropical Cyclone Activity

Atlantic Ocean: There are no active tropical cyclones

Caribbean: There are no active tropical cyclones

Gulf of Mexico: There are no active tropical cyclones

Eastern Pacific: There are no active tropical cyclones

Invest 90E

A well-defined area of low pressure producing gale-force winds is located more than 1000 miles east-northeast of Hilo, Hawaii. Shower and thunderstorm activity has recently increased in coverage and organization near the center. While environmental conditions appear only marginally favorable for additional development, if this activity persists, it could result in the formation of a short-lived subtropical or tropical cyclone over the next day or so. By Friday, environmental conditions are expected to become unfavorable for additional development.

* Formation chance through 48 hours…medium…40 percent
* Formation change through 5 days…medium…40 percent

Here’s the link to the National Hurricane Center (NHC)