West Side

Today: Windy. Partly sunny with isolated showers. Highs 81 to 87. East winds up to 25 mph increasing to northeast in the afternoon. Chance of rain 20 percent.

Tonight: Windy. Mostly cloudy with isolated showers. Lows 67 to 74. Northeast winds 10 to 30 mph decreasing to up to 30 mph after midnight. Gusts up to 50 mph. Chance of rain 20 percent.

Tuesday: Partly sunny in the morning then becoming mostly sunny. Breezy. Isolated showers. Highs 81 to 86. Northeast winds up to 25 mph shifting to the east 10 to 25 mph in the afternoon. Gusts up to 45 mph. Chance of rain 20 percent.

South Side

Today: Mostly sunny in the morning then becoming partly sunny. Breezy. Highs around 90. Northeast winds up to 25 mph. Gusts up to 45 mph in the afternoon.

Tonight: Mostly cloudy. Breezy. Lows 67 to 75. Northeast winds 10 to 25 mph with gusts to 45 mph.

Tuesday: Mostly sunny. Breezy. Highs around 89. Northeast winds 10 to 25 mph with gusts to 45 mph.

North Shore

Today: Breezy. Partly sunny with scattered showers. Highs 80 to 86 near the shore to around 66 near 5000 feet. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 71 near the shore to around 51 near 5000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Tuesday: Partly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 80 to 86 near the shore to around 67 near 5000 feet. East winds 10 to 25 mph. Chance of rain 40 percent.

Central Maui

Today: Partly sunny. Breezy. Isolated showers in the morning. Highs 82 to 90. Northeast winds 10 to 25 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated showers. Lows 67 to 72. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Tuesday: Partly sunny in the morning then becoming mostly sunny. Breezy. Isolated showers. Highs 81 to 89. Northeast winds 10 to 25 mph. Chance of rain 20 percent.

Upcountry

Today: Partly sunny. Windy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 65 at the visitor center to around 71 at the summit. East winds up to 30 mph increasing to 10 to 30 mph in the afternoon. Chance of rain 50 percent.

Tonight: Windy. Mostly cloudy with isolated showers. Lows around 47 at the visitor center to around 49 at the summit. East winds up to 30 mph. Chance of rain 20 percent.

Tuesday: Windy. Partly sunny with isolated showers in the morning, then mostly sunny in the afternoon. Highs around 64 at the visitor center to around 73 at the summit. East winds 10 to 30 mph. Chance of rain 20 percent.

East Maui

Today: Breezy. Partly sunny with scattered showers. Highs 80 to 86 near the shore to around 66 near 5000 feet. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 71 near the shore to around 51 near 5000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Tuesday: Partly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs 80 to 86 near the shore to around 67 near 5000 feet. East winds 10 to 25 mph. Chance of rain 40 percent.

Lanai City

Today: Mostly sunny in the morning then becoming partly sunny. Windy. Isolated showers. Highs 74 to 83. Northeast winds up to 25 mph increasing to 10 to 30 mph in the afternoon. Chance of rain 20 percent.

Tonight: Windy. Mostly cloudy with isolated showers. Lows around 64. Northeast winds 10 to 30 mph. Chance of rain 20 percent.

Tuesday: Partly sunny. Breezy. Isolated showers in the afternoon. Highs 74 to 82. Northeast winds 10 to 25 mph. Chance of rain 20 percent.

Kaunakakai

Today: Partly sunny. Breezy. Isolated showers in the morning. Highs 73 to 90. East winds 10 to 25 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated showers. Lows 59 to 73. Northeast winds 10 to 25 mph decreasing to up to 25 mph after midnight. Gusts up to 45 mph. Chance of rain 20 percent.

Tuesday: Partly sunny in the morning then becoming mostly sunny. Breezy. Highs 72 to 89. East winds 10 to 25 mph with gusts to 45 mph.

Detailed Forecast

Synopsis

A strong high pressure ridge north of the Hawaiian Islands will keep breezy to windy trade winds in the forecast through Tuesday. The strongest winds remain in the forecast for the windier areas of Maui and Hawaii Counties. Dry weather conditions will combine with these strong gusty winds to produce elevated fire danger across the state. Wind speeds will decrease from Wednesday onward. A stable ridge aloft will keep only brief passing showers in the forecast favoring windward and mountain areas. Leeward areas will remain dry through the week.

Discussion

The two main weather stories this week will revolve around the breezy to windy trade winds and the dry afternoon humidity levels lasting through Tuesday. This mornings satellite imagery east of the islands shows stable stratocumulus clouds riding in on the trade winds. The low tops of these clouds will only produce brief passing showers as they are driven up the windward mountain slopes of each island in this stable environment. Temperature inversion heights will range from 6,000 to 7,000 feet today, dropping into the 5,000 to 6,000 foot range on Tuesday. Wind speeds observations on Sunday afternoon verified with our low end Wind Advisory forecast. Several areas observed sustained winds around 30 MPH with gusts from 40 to 50 MPH over the windier areas of Molokai, Maui and the Big Island. Wind speed trends are expected to increase slightly later today. Wind observations on Kauai and Oahu showed lower speeds, below advisory thresholds with sustained winds in the 15 to 25 MPH range along with higher gusts up to 35 MPH.
The Wind Advisory for windier areas of Maui and Hawaii Counties was expanded in coverage to include the summits of Mauna Kea and Mauna Loa, and also extended in time for 24 hours now lasting through Tuesday afternoon. Wind speeds will likely peak later today and tonight before a slight decreasing trend for most areas on Tuesday. Trade wind speeds will continue to trend lower each day through the week, reaching more moderate wind speed ranges by this weekend. The combination of stronger winds in the short term forecast along with stable and dry minimum afternoon humidity levels will elevate fire weather concerns each afternoon through Tuesday. Please refer to the Fire Weather section below for more details.

Aviation

Stable conditions with breezy to windy trade winds will continue across the state through Tuesday. Passing showers will favor windward and mountain areas in the overnight to early morning hours, bringing the potential for brief MVFR conditions. Otherwise, VFR conditions will prevail.
AIRMET Tango remains in effect for moderate low-level turbulence over and downwind of island terrain. This AIRMET will likely persist as strong trade winds remain in the forecast.

Marine

High pressure will remain far north of the islands for the next several days, which will support fresh to strong trades across the area. The Small Craft Advisory has been extended until 6PM Tuesday, but this will likely need to be extended for at least some zones as the gusty trades persist. The surface high will move eastward and weaken slightly during the second half of the week, but winds are likely to remain locally breezy in the typical windier channels and waters.
South shore surf is expected to slowly decline as a south swell fades through Monday. The next small, long-period south swell is expected to arrive late Tuesday, peaking on Wednesday. This swell may boost south-facing shore surf heights to near summertime averages for the middle of the week. It will then decline through Friday.
Surf along east-facing shores will be rough and choppy in response to the gusty easterly trade winds throughout the next few days.

Fire weather

Breezy to windy trade winds with stable and dry conditions will persist through Tuesday. Minimum relative humidity at lower leeward elevations will likely fall to around 45 percent each afternoon, and with the inversion dropping to as low as 5,000 feet winds will become gusty over and downwind of island mountains. This will result in near critical fire weather conditions over dry leeward areas at times, though no headlines (watches or warnings) are due since the Keetch Byram Drought Index will remain below the 600 threshold at Honolulu.

HFO Watches/Warnings/Advisories

Wind Advisory until 6 PM HST Tuesday for Lanai Mauka, Kahoolawe, Maui Windward West, Maui Leeward West, Kohala, Big Island Summits, Molokai, Lanai Windward, Lanai Leeward, Lanai South, Maui Central Valley North, Maui Central Valley South, Windward Haleakala, South Haleakala, Big Island South, Big Island Southeast, Big Island North.
Small Craft Advisory until 6 PM HST Tuesday for all Hawaiian waters.

Data Courtesy of NOAA.gov