West Side

Today: Mostly sunny in the morning then becoming partly sunny. Highs 82 to 87. East winds up to 10 mph.

Tonight: Partly cloudy. Isolated showers in the evening. Lows 69 to 76. Northeast winds around 10 mph. Chance of rain 20 percent.

Sunday: Mostly cloudy. Isolated showers in the morning. Highs 81 to 86. Southeast winds up to 10 mph. Chance of rain 20 percent.

South Side

Today: Mostly sunny in the morning then becoming partly sunny. Highs around 90. South winds up to 10 mph shifting to the west in the afternoon.

Tonight: Partly cloudy. Lows 69 to 77. Northeast winds around 10 mph.

Sunday: Mostly cloudy. Highs around 89. Light winds becoming southeast around 10 mph in the afternoon.

North Shore

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 81 to 86 near the shore to around 68 near 5000 feet. East winds 10 to 15 mph decreasing to up to 15 mph in the afternoon. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows around 72 near the shore to around 53 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Sunday: Mostly cloudy with isolated showers. Highs around 83 near the shore to around 67 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Central Maui

Today: Mostly sunny in the morning then becoming partly sunny. Highs 84 to 91. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon.

Tonight: Partly cloudy. Lows 69 to 74. Northeast winds around 10 mph.

Sunday: Mostly cloudy. Highs 83 to 90. Northeast winds 10 to 15 mph.

Upcountry

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 64 at the visitor center to around 68 at the summit. East winds up to 10 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers in the evening, then partly cloudy after midnight. Lows around 50 at the visitor center to around 47 at the summit. East winds around 10 mph. Chance of rain 40 percent.

Sunday: Partly sunny. Isolated showers in the morning. Highs around 64 at the visitor center to around 68 at the summit. East winds up to 10 mph. Chance of rain 20 percent.

East Maui

Today: Partly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 81 to 86 near the shore to around 68 near 5000 feet. East winds 10 to 15 mph decreasing to up to 15 mph in the afternoon. Chance of rain 50 percent.

Tonight: Partly cloudy with isolated showers. Lows around 72 near the shore to around 53 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Sunday: Mostly cloudy with isolated showers. Highs around 83 near the shore to around 67 near 5000 feet. East winds 10 to 15 mph. Chance of rain 20 percent.

Lanai City

Today: Partly sunny with isolated showers. Highs 75 to 82. East winds up to 10 mph. Chance of rain 20 percent.

Tonight: Mostly cloudy with isolated showers. Lows around 67. Northeast winds around 10 mph in the evening becoming light. Chance of rain 20 percent.

Sunday: Mostly cloudy. Highs 74 to 82. Light winds.

Kaunakakai

Today: Partly sunny with isolated showers. Highs 75 to 91. East winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Lows 61 to 75. East winds around 10 mph.

Sunday: Mostly cloudy. Isolated showers in the afternoon. Highs 74 to 90. East winds up to 10 mph. Chance of rain 20 percent.

Detailed Forecast

Synopsis

A nearby trough will maintain light winds over the region today. with a brief uptick in winds expected. An upper level low moving south towards the islands Sunday night will bring the trough closer to the islands, and bring another round of light winds and showers to the region, with a more unstable airmass over the islands midweek.

Discussion

There have been changes to the forecast, specifically to remove the mention of thunderstorms later in the forecast. While an unstable airmass is expected midweek, it is likely too early to identify specific areas of thunderstorms.
Winds may be weak enough today to allow for some localized afternoon sea breezes, however we are not expecting a repeat of the afternoon convection primarily because the main moisture axis has shifted south of the region.
An upper level low to the north of the islands is expected to sink southward over the next couple of days and will bring another unstable airmass to the region. Moisture upstream of the islands will be carried in by the east to southeast low level flow. The National Blend of Models (NBM) along with the GFE and ECMWF all show the chance for thunderstorms as early as Tuesday night, and continuing through the rest of the week. The main question will be how widespread the threat will be. Will be monitoring future model runs to determine the extent of the threat.

Aviation

Light east to southeast winds across the islands are expected over the next couple of days. VFR conditions are expected across most locations, however particularly for today and tomorrow, localized afternoon sea breezes may bring an increase in interior clouds and showers over the smaller islands. While no AIRMETs are in effect in the pre-dawn hours, there is a chance that such development of clouds and showers could prompt the need for an AIRMET for mountain obscuration.

Marine

A troughing pattern will continue to weaken trade winds near Hawaiian waters into early next week, allowing for daytime onshore sea breezes to continue along nearshore leeward coastal waters. An upper level disturbance lingering north of the island chain will bring periods of enhanced showers through the weekend. Long range guidance shows increasing southeasterly winds by the middle of next week in an unstable weather pattern with the potential for increasing shower coverage and thunderstorms.
A mix of a small medium-period northwest (330 deg) swell and a small short to medium period north northeast (020 deg) swell will maintain small surf along north facing shores today, fading into Sunday morning. The smaller forerunners of a moderate to large long period northwest (320 deg) swell will build into Hawaiian waters starting Sunday afternoon. This swell energy will build to High Surf Advisory (HSA) levels by Monday, then likely hold through Tuesday before slowly falling below HSA thresholds from Wednesday onward. Predicting slightly higher swell heights than the latest swell model guidance indicates, as recent swell model forecasts were too low as compared to nearshore ground truth buoy observations.
Surf along south facing shores will remain small through the weekend with a series of background south and southwest swells through early next week. East facing shores will remain small as a small, medium period easterly swell, originating from Tropical Cyclone Priscilla in the East Pacific, will build into the islands starting later this afternoon and lasting into Sunday.
Peak high tides associated with the lunar cycle will lead to minor coastal flooding along shorelines and low lying coastal areas during the peak high tide through this morning. A Coastal Flood Statement is in effect for all coastal areas, and will likely be cancelled later today following the peak morning high tide cycle.

Fire weather

Light winds and isolated to scattered showers will help maintain fire weather below critical thresholds for the next several days. Inversion heights will range from 7,000 to 9,000 feet.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov