Hilo

Today: Mostly cloudy with scattered showers. Highs around 84 near the shore to 68 to 73 at 4000 feet. Northeast winds up to 15 mph shifting to the east in the afternoon. Chance of rain 50 percent.

Tonight: Cloudy with scattered showers. Lows around 66 near the shore to around 54 at 4000 feet. Northeast winds up to 10 mph shifting to the west after midnight. Chance of rain 50 percent.

Sunday: Cloudy with scattered showers. Highs around 84 near the shore to 68 to 73 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Kona

Today: Mostly sunny in the morning then becoming mostly cloudy. Isolated showers. Highs 80 to 85 near the shore to around 68 near 5000 feet. North winds up to 10 mph in the morning becoming light. Chance of rain 20 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Isolated showers. Lows 70 to 75 near the shore to around 55 near 5000 feet. Light winds becoming northeast around 10 mph after midnight. Chance of rain 20 percent.

Sunday: Mostly sunny in the morning then becoming mostly cloudy. Isolated showers. Highs 80 to 85 near the shore to around 68 near 5000 feet. East winds around 10 mph shifting to the south in the afternoon. Chance of rain 20 percent.

Waimea

Today: Partly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 82 near the shore to 69 to 79 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 66 near the shore to 54 to 62 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Sunday: Mostly cloudy. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 82 near the shore to 69 to 79 near 3000 feet. East winds 10 to 20 mph. Chance of rain 40 percent.

Kohala

Today: Partly sunny. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 82 near the shore to 69 to 79 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows around 66 near the shore to 54 to 62 near 3000 feet. East winds 10 to 20 mph. Chance of rain 50 percent.

Sunday: Mostly cloudy. Breezy. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 82 near the shore to 69 to 79 near 3000 feet. East winds 10 to 20 mph. Chance of rain 40 percent.

South Big Island

Today: Mostly sunny in the morning then becoming partly sunny. Breezy. Isolated showers. Highs around 85 near the shore to around 72 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Breezy. Partly cloudy with isolated showers. Lows 68 to 73 near the shore to around 53 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Sunday: Breezy. Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs around 85 near the shore to around 72 near 5000 feet. East winds 10 to 20 mph. Chance of rain 20 percent.

Puna

Today: Mostly cloudy with scattered showers. Highs around 84 near the shore to 68 to 73 at 4000 feet. Northeast winds up to 15 mph shifting to the east in the afternoon. Chance of rain 50 percent.

Tonight: Cloudy with scattered showers. Lows around 66 near the shore to around 54 at 4000 feet. Northeast winds up to 10 mph shifting to the west after midnight. Chance of rain 50 percent.

Sunday: Cloudy with scattered showers. Highs around 84 near the shore to 68 to 73 at 4000 feet. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Waikoloa

Today: Mostly sunny in the morning then becoming mostly cloudy. Breezy. Isolated showers. Highs around 85 near the shore to 69 to 75 above 4000 feet. East winds up to 20 mph shifting to the north 10 to 20 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 73 near the shore to 51 to 58 above 4000 feet. East winds up to 15 mph shifting to the southeast after midnight. Chance of rain 20 percent.

Sunday: Mostly sunny in the morning, then mostly cloudy with isolated showers in the afternoon. Highs around 85 near the shore to 69 to 75 above 4000 feet. East winds around 10 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A high pressure ridge remains locked in place north of the Hawaiian Islands through next Friday. Expect moderate to locally breezy trade winds with brief periods of passing showers, mainly over windward and mountain areas in the overnight to early morning hours. Another enhancement in shower coverage may develop over the islands on Wednesday and Thursday.

Discussion

The morning satellite imagery continues to show a weak upper level low drifting through the islands within a narrow upper level trough (TUTT) pattern. Radar imagery and surface observations confirm this upper low is lifting the trade wind temperature inversion height enough to allow a return to brief periods of windward and mountain area showers over most islands. Satellite microwave imagery from this afternoon already show signs of increasing wind speeds across the region.
The weather pattern has not changed much over the past 24 hours with the high pressure ridge building north of the islands through Saturday. Trade wind speeds will increase into the moderate to breezy range lasting through the end of next week. Meanwhile, three weak upper level lows will pass over the state from east to west within a narrow upper trough pattern (Tropical Upper Tropospheric Trough also known as the TUTT). These passing lows and stronger trade wind speeds will combine forces and produce small amounts of atmospheric lift. This additional lift will lift trade wind inversion heights enough to allow for brief periods of passing showers over all islands through much of next week. This slight increase in shower coverage will mainly affect windward and mountain areas and favor the overnight to early morning hours.
Long range global weather model solutions continue to show a band of unsettled clouds moving through the islands on Wednesday and Thursday. This cloud band is associated with the remnants of an old cold front that dissipated north of the region. If this band moves into the islands as the current American GFS and European models predict, then we could see another increase in shower coverage mainly over windward and mountain sections of the islands. There is a decent chance that some of the stronger showers in these bands will spill over light rainfall amounts into the drier leeward areas on Wednesday and Thursday nights. Stay tuned.

Aviation

Moderate to breezy easterly trade winds are expected through the weekend, with clouds and showers favoring windward and mauka locations overnight through the morning periods. MVFR conditions are possible in and around passing showers, but the limited coverage should preclude the need for an AIRMET for mountain obscuration.
AIRMET Tango may be needed for low-level mechanical turbulence over and just downwind of mountain ranges Saturday afternoon.

Marine

Winds will increase into the moderate to locally strong range through this weekend. The Small Craft Advisory (SCA) remains in effect for the typically windier waters around the Big Island and Maui County. The Pailolo channel has been added to this SCA as of this morning's package. Additional expansions of the SCA may be needed later in the forecast period.
No significant swells are expected through the next week. A small northwest swell is due Sunday and Monday. Expect background summertime surf for south facing shores, though a small pulse from the southwest is possible during the middle of next week. Small, short-period surf along east facing shores will build to seasonal average over the weekend as trade winds strengthen, then hold into next week.

HFO Watches/Warnings/Advisories

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

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Data Courtesy of NOAA.gov