West Side

Today: Mostly sunny. Breezy. Highs 74 to 85. East winds up to 15 mph increasing to 10 to 20 mph in the afternoon.

Tonight: Mostly clear. Lows 63 to 72. East winds up to 15 mph.

Tuesday: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 72 to 83. Light winds. Chance of rain 40 percent.

South Side

Today: Sunny. Highs 75 to 86. North winds up to 15 mph shifting to the northeast in the afternoon.

Tonight: Mostly clear. Lows 64 to 69. North winds up to 10 mph.

Tuesday: Sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 74 to 85. Light winds. Chance of rain 20 percent.

North Shore

Today: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs around 80 near the shore to around 65 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 67 to 72 near the shore to around 52 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 50 percent.

Tuesday: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 78 to 83 near the shore to around 65 near 5000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Central Maui

Today: Sunny and breezy. Highs 80 to 86. Northeast winds up to 20 mph increasing to 10 to 20 mph in the afternoon.

Tonight: Mostly clear. Lows around 66. Northeast winds 10 to 15 mph shifting to the east after midnight.

Tuesday: Mostly sunny in the morning, then partly sunny with isolated showers in the afternoon. Highs 80 to 85. Northeast winds up to 10 mph. Chance of rain 20 percent.

Upcountry

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 52 to 67. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly clear. Isolated showers in the evening, then scattered showers after midnight. Lows around 43 at the visitor center to around 41 at the summit. East winds 10 to 15 mph decreasing to up to 15 mph after midnight. Chance of rain 50 percent.

Tuesday: Mostly sunny with isolated showers in the morning, then partly sunny with scattered showers in the afternoon. Highs 51 to 66. East winds up to 15 mph. Chance of rain 50 percent.

East Maui

Today: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs around 80 near the shore to around 65 near 5000 feet. East winds up to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy in the evening then becoming partly cloudy. Scattered showers. Lows 67 to 72 near the shore to around 52 near 5000 feet. Southeast winds up to 15 mph. Chance of rain 50 percent.

Tuesday: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 78 to 83 near the shore to around 65 near 5000 feet. East winds up to 10 mph. Chance of rain 50 percent.

Lanai City

Today: Mostly sunny. Breezy. Highs 68 to 79. Northeast winds up to 15 mph increasing to 10 to 20 mph in the afternoon.

Tonight: Clear. Lows 58 to 65. Northeast winds up to 10 mph in the evening becoming light.

Tuesday: Mostly sunny in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 68 to 78. Light winds. Chance of rain 50 percent.

Kaunakakai

Today: Mostly sunny. Highs 67 to 86. East winds 10 to 15 mph.

Tonight: Mostly clear. Lows 55 to 71. East winds 10 to 15 mph.

Tuesday: Mostly sunny with isolated showers in the morning, then mostly cloudy with scattered showers in the afternoon. Highs 67 to 86. East winds up to 10 mph. Chance of rain 40 percent.

Detailed Forecast

Synopsis

A high pressure ridge just north of the Hawaiian Islands will continue to weaken in advance of a cold front approaching the islands from the northwest. Moderate trade winds will weaken and transition to light southeasterly to southerly winds across the region. The cold front continues to move into the western half of the state from Wednesday to Thursday. Expect cloudy skies and showers along the frontal band as it moves over each island with moderate to breezy cool northerly winds blowing in behind the frontal boundary. Light east to southeast winds will continue through the rest of the week as yet another cold front moves into the Hawaii region next weekend.

Discussion

Looking at this mornings satellite imagery we see a fairly stable pattern under the influence of a weak upper level ridge. A large band of cirrus clouds associated with an approaching cold front is currently far northwest of Hawaii passing through Midway Atoll this morning. This cold front will bring increasing clouds and showers to the western Hawaiian Islands from late Wednesday through Thursday. One wrinkle in this pattern is the presence of a weak upper low shown on water vapor satellite imagery just east of the Big Island. Expect one more day of easterly trade winds with hybrid onshore sea breezes during the daylight hours along western terrain sheltered slopes of each island. Expect brief passing showers will remain in the short range forecast today, favoring windward and mountain areas. Trade winds will diminish on Tuesday with lighter southeasterly to southerly winds developing.
By Tuesday the approaching cold front will continue to break down and drive the large scale ridge directly over the islands, producing light southeasterly to southerly winds across the Hawaii region. A combination of increasing stable subsidence and southeasterly cloud steering winds will produce fairly dry conditions across the region through Tuesday night.
From Wednesday afternoon through Wednesday night the cold front will drift over the western islands of Kauai and Niihau, reaching the islands of Oahu and Molokai by Thursday morning. Expect increasing clouds and numerous showers along the frontal cloud band as it drifts through each island. Moderate to breezy cool northerly winds will blow in as the front passes through each island. The latest consensus of models shows the forward motion of the frontal cloud band stalling out over the islands in Maui County from Thursday night into Friday morning, then the band will diminish and lift northward as high pressure builds in to the north of the state.
Friday through Saturday, large scale winds will remain light and variable during this time period as a weak high pressure system, sandwiched between two cold frontal systems passes just north of the region. The next weak cold frontal system will approach the state from the northwest late Saturday into Sunday. The latest long range model guidance shows large inconsistencies on when or if this frontal cloud band will bring another round of rain showers to the western islands. For now the western islands of Kauai and Niihau seem to hold the best chances for a Hana Hou (encore) rainfall event, possibly starting by Saturday night. Stay tuned for updates to next weekends weather conditions, as the forecast for the western Hawaiian Islands will likely evolve over time.

Aviation

Brief passing showers are possible today, mainly over island windward and mountain areas. VFR conditions will prevail outside of showers.
AIRMET Tango remains in effect for moderate upper level turbulence across the island chain. This area of turbulence associated with an upper level subtropical jet stream will move southeast today, with this moderate turbulence area decreasing by this afternoon.

Marine

An area of high pressure will remain north of the Hawaii region, producing gentle to moderate easterly winds through today, then decrease and veer more southeasterly to southerly Tuesday to Wednesday as another cold front moves into the region from the northwest. This front may move into the western Hawaiian islands late Wednesday into Thursday, then diminish by Friday.
The current medium-period north-northwest (340-350 degree) swell will continue to slowly fade today, bringing surf back down to below average levels for this time of year. The next two long to medium-period overlapping northwest (310-320 degree) swells will arrive on today, boosting surf along north and west facing shores and possibly reaching advisory levels by Wednesday.
Choppy east shore surf will remain small, then decline further over the next few days as trades gradually ease. Expect minimal background energy for south facing shores, keeping south shore surf heights just above flat levels.

Fire weather

Conditions remain below critical fire thresholds through the week as winds remain light and RH elevated. Temperature inversion heights over Maui and the Big Island will range from 5,500 to 6,500 feet today.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov