Hilo

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 85 near the shore to 70 to 75 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 69 near the shore to around 55 at 4000 feet. North winds up to 10 mph. Chance of rain 50 percent.

Monday: Partly sunny with scattered showers. Highs around 85 near the shore to 70 to 75 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Kona

Today: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 83 to 88 near the shore to around 70 near 5000 feet. West winds up to 10 mph. Chance of rain 40 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows 70 to 75 near the shore to around 56 near 5000 feet. Light winds. Chance of rain 20 percent.

Monday: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 83 to 88 near the shore to around 70 near 5000 feet. Southwest winds up to 10 mph. Chance of rain 40 percent.

Waimea

Today: Breezy. Mostly sunny with scattered showers. Highs around 83 near the shore to 70 to 80 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Breezy. Partly cloudy with scattered showers. Lows around 69 near the shore to 57 to 63 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Monday: Mostly sunny in the morning then becoming partly sunny. Breezy. Scattered showers. Highs around 83 near the shore to 70 to 80 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Kohala

Today: Breezy. Mostly sunny with scattered showers. Highs around 83 near the shore to 70 to 80 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Tonight: Breezy. Partly cloudy with scattered showers. Lows around 69 near the shore to 57 to 63 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

Monday: Mostly sunny in the morning then becoming partly sunny. Breezy. Scattered showers. Highs around 83 near the shore to 70 to 80 near 3000 feet. East winds 10 to 25 mph. Chance of rain 50 percent.

South Big Island

Today: Breezy. Mostly sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs around 87 near the shore to around 74 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Tonight: Breezy. Mostly cloudy with isolated showers in the evening, then partly cloudy after midnight. Lows around 71 near the shore to around 54 near 5000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Monday: Breezy. Mostly sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs around 87 near the shore to around 74 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.

Puna

Today: Partly sunny. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 85 near the shore to 70 to 75 at 4000 feet. Northeast winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 70 percent.

Tonight: Mostly cloudy with scattered showers. Lows around 69 near the shore to around 55 at 4000 feet. North winds up to 10 mph. Chance of rain 50 percent.

Monday: Partly sunny with scattered showers. Highs around 85 near the shore to 70 to 75 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 50 percent.

Waikoloa

Today: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 87 near the shore to 71 to 77 above 4000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy. Breezy. Isolated showers in the evening. Lows around 73 near the shore to 52 to 59 above 4000 feet. East winds up to 20 mph. Chance of rain 20 percent.

Monday: Mostly sunny. Breezy. Isolated showers in the afternoon. Highs around 87 near the shore to 71 to 77 above 4000 feet. Northeast winds up to 20 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

High pressure far northwest of the islands will keep moderate to breezy trade winds in place through late next week, with only minor fluctuations in strength. Fairly typical trade wind weather will prevail, with showers favoring windward and mauka areas and a stray shower reaching leeward communities at times.

Discussion

Currently at the surface, a 1028 mb high centered around 1500 miles northwest of Honolulu continues to drive moderate to locally breezy trade winds across the island chain early this morning. Infrared satellite imagery shows partly to mostly cloudy across the state, with cloud coverage the greatest over windward and mauka areas. Radar imagery shows scattered to numerous showers moving into windward slopes and coasts, with some of these showers making it into leeward communities as well. Main short term focus revolves around trade wind trends and rain chances.
High pressure will remain anchored to the northwest of the islands today, while a cold front drops steadily southward well to the north of the state. Little change in trade wind strength is expected, with moderate to breezy trade winds prevailing. The high northwest of the state will weaken and shift eastward tonight and Monday, while the front edges southward and closer to the island chain, eventually stalling out well north of the islands Monday night. This should ease the trades ever so slightly on Monday. The high will then re-strengthen north-northeast of the state Tuesday through late next week, bringing a return of breezy trade winds.
As for the remaining weather details, fairly typical trade wind weather will prevail during the next 7 days, although there could be a slight decrease in shower coverage this afternoon through Tuesday. Overall, showers will favor windward and mauka areas through the period, particularly at night and during the early morning hours, with a few showers reaching leeward areas at times.

Aviation

A high pressure system far northwest of the islands will continue to produce moderate to locally breezy trade winds. Satellite imagery this morning continues to show clouds and showers riding into the islands on the trade winds. Expect passing showers to last through the early morning hours mainly over windward and mountain sections of each island. Some of these stronger showers will drift into leeward airfields. Expect decreasing shower trends for all islands after 20Z this morning.
AIRMET Sierra for mountain obscuration remains in effect over north through east sections of Kauai Oahu Molokai Maui and Big Island. This AIRMET will likely diminish by 20Z.
AIRMET Tango for moderate low level turbulence remains in effect over and south through west of all island mountains. This AIRMET will likely continue through this afternoon.

Marine

A surface high pressure system located far northwest of the state will maintain locally strong trade winds early this week. As a result, the Small Craft Advisory (SCA) has been extended through Tuesday night for the typically windier waters adjacent to the islands of Maui County and the Big Island. The latest forecast indicates the trade winds should remain locally strong most of this week. Therefore, the SCA will eventually need to be extended through mid-week for the same typically windier waters in the vicinity of the eastern islands. Note that SCA conditions may develop over additional waters by mid-week as high pressure builds far north of the state, and the trade winds strengthen slightly.
The current small, long-period southwest (210 degrees) swell will continue to spread over the area today. This southwest swell energy combined with a lingering southeast trade wind swell will likely maintain small surf along south facing shores early this week.
The nearshore buoys exposed to the small north-northwest (330 degrees) swell are showing a wave height of around 2 feet and a wave period near 11 seconds. This swell will produce a small bump in surf heights along exposed north and west facing shores through early Monday. In addition, a small north (350-360 degrees) swell may arrive around Tuesday, followed by a modest north- northeast (020 degrees) swell from Thursday through Friday.
Moderate, rough surf will likely persist along east facing shores this morning. The surf may lower slightly along east facing shores from later today and tonight into Tuesday due to a subtle weakening of the trade winds. Moderate, rough surf may return along east facing shores by mid-week due to strengthening of the trade winds.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 AM HST Wednesday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

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Data Courtesy of NOAA.gov