West Side

Today: Mostly sunny with isolated showers. Highs around 84. East winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 68 to 76. East winds 10 to 15 mph. Chance of rain 20 percent.

Tuesday: Sunny. Highs around 84. East winds up to 15 mph.

South Side

Today: Sunny. Isolated showers in the morning. Highs around 89. Light winds becoming north up to 15 mph in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Lows 70 to 76. North winds 10 to 15 mph.

Tuesday: Sunny. Highs around 89. North winds 10 to 15 mph.

North Shore

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 80 to 86 near the shore to around 68 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows around 73 near the shore to around 53 near 5000 feet. East winds 10 to 15 mph. Chance of rain 40 percent.

Tuesday: Sunny. Isolated showers in the morning. Highs 80 to 86 near the shore to around 67 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Central Maui

Today: Mostly sunny. Isolated showers in the morning. Highs 83 to 90. Northeast winds up to 15 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 69 to 74. Northeast winds 10 to 15 mph. Chance of rain 20 percent.

Tuesday: Sunny. Highs 83 to 90. Northeast winds 10 to 15 mph.

Upcountry

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 66 at the visitor center to around 69 at the summit. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows around 50 at the visitor center to around 48 at the summit. East winds 10 to 15 mph. Chance of rain 20 percent.

Tuesday: Sunny. Highs around 65 at the visitor center to around 69 at the summit. Southeast winds up to 15 mph.

East Maui

Today: Partly sunny in the morning then becoming mostly sunny. Scattered showers. Highs 80 to 86 near the shore to around 68 near 5000 feet. East winds up to 15 mph. Chance of rain 50 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows around 73 near the shore to around 53 near 5000 feet. East winds 10 to 15 mph. Chance of rain 40 percent.

Tuesday: Sunny. Isolated showers in the morning. Highs 80 to 86 near the shore to around 67 near 5000 feet. East winds up to 15 mph. Chance of rain 20 percent.

Lanai City

Today: Mostly sunny with isolated showers. Highs 74 to 83. East winds up to 10 mph. Chance of rain 20 percent.

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

Tuesday: Sunny. Highs 74 to 82. Light winds.

Kaunakakai

Today: Sunny. Isolated showers in the morning. Highs 73 to 90. East winds 10 to 15 mph. Chance of rain 20 percent.

Tonight: Mostly clear with isolated showers. Lows 61 to 75. East winds 10 to 15 mph. Chance of rain 20 percent.

Tuesday: Sunny. Highs 73 to 90. East winds 10 to 15 mph.

Detailed Forecast

Synopsis

Upper-level ridging returns, bringing more stable and drier air to the islands, and will support moderate to locally breezy trades for the next couple of days. Expect fewer clouds and shower activity during this time. Despite the introduction of a shortwave by mid-week, overall shower activity will be reduced throughout the week, amplifying fire weather concerns. Trades remain light thereafter through the weekend with shower activity limited to windward and mauka areas.

Discussion

As the upper-level low and associated trough continues to trek away northwest of the islands, ridging quickly fills the void from the east, bringing more stability and drier air to the islands. The surface high, anchored well northeast of the state, will tighten the local pressure gradient, aiding in driving moderate to locally breezy trades. Expect fewer clouds and reduced shower activity during this time, lasting through the next couple days. However, as drier conditions develop, it will amplify short term fire weather conditions, especially over leeward areas across the state where rainfall has been deprived (see Fire weather section below for further information).
By mid-week, a mid-level shortwave trough propagates in from the east, slightly disrupting the trades pattern and opens the doors for sea breeze activity, predominately for western slopes of island mountains. Moreover, this shortwave trough may also briefly enhance shower activity across the western half of the state, namely Kauai and Oahu. This will be short-lived, however, as drier and more stable pattern continue to funnel into the vicinity of the state, courtesy of the ridging aloft. Otherwise, expect shower activity to be limited to windward and mauka areas.
Latest model guidance retains lighter winds generally throughout the remainder of the week and into the weekend, with exception to some localized areas, but longer-range models are hinting at moderate to breezy trades returning by the end of the forecast period.

Aviation

High pressure northwest of the islands will enhance moderate to locally breezy trades are expected over the next couple of days. Brief periods of MVFR conditions are likely in low ceilings and showers, predominately over windward and mauka locations. Otherwise, VFR conditions are expected to prevail.
AIRMET Sierra for mountain obscuration remains in effect for N thru S sections of Maui and from Upolu Point to PHTO to Apua Point on Big Island, expected to continue beyond 16z.

Marine

A high pressure ridge to build back into the region and strengthen trade winds into the moderate to locally strong range into Thursday. Lighter winds are forecast from Thursday night into the weekend.
Several pulses of southerly and southwesterly swell will continue to boost surf heights along south and some of the west facing shores this week.
Surf along east facing shores will remain small and choppy. Surf along north facing shores will remain nearly flat through the forecast period.
Peak high tides associated with the lunar cycle could lead to minor coastal flooding along shorelines and low lying coastal areas through Wednesday during the daily peak tide each afternoon.

Fire weather

Drier conditions are expected to develop this week and will exacerbate short term fire weather conditions, predominately over the leeward areas where rainfall has deprived. Latest KBDI values are on the cusp of 600 threshold and are expected to surpass the threshold this week. Additionally, humidity values are expected to fall into the upper-40s to lower-50s under moderate to locally breezy winds through the next several days.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Tuesday for Kaiwi Channel, Maui County Windward Waters, Maui County Leeward Waters, Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov