Photo Credit: Tyler Rooke

West Side

Today: Mostly sunny with scattered showers. Highs 78 to 86. East winds 10 to 15 mph in the morning becoming light. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows 64 to 70. Northeast winds 10 to 15 mph. Chance of rain 50 percent.

Thanksgiving Day: Sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 81 to 87. Light winds becoming south up to 15 mph in the afternoon. Chance of rain 40 percent.

South Side

Today: Breezy. Sunny with isolated showers. Highs around 85. Northeast winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Mostly clear with isolated showers. Lows around 65. North winds 10 to 15 mph. Chance of rain 20 percent.

Thanksgiving Day: Sunny and breezy. Highs around 87. North winds 10 to 20 mph.

North Shore

Today: Mostly cloudy with showers. Highs 78 to 83 near the shore to around 63 near 5000 feet. East winds 10 to 15 mph. Chance of rain 80 percent.

Tonight: Cloudy with showers. Lows 62 to 69 near the shore to 47 to 52 near 5000 feet. East winds 10 to 15 mph. Chance of rain 90 percent.

Thanksgiving Day: Breezy. Occasional showers in the morning, then scattered showers in the afternoon. Highs 79 to 84 near the shore to around 63 near 5000 feet. East winds 10 to 15 mph becoming up to 20 mph in the afternoon. Chance of rain near 100 percent.

Central Maui

Today: Breezy. Partly sunny with scattered showers. Highs 81 to 86. Northeast winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Mostly cloudy with scattered showers. Lows 63 to 69. Northeast winds around 10 mph. Chance of rain 50 percent.

Thanksgiving Day: Sunny and breezy. Isolated showers in the morning. Highs 83 to 88. East winds 10 to 20 mph. Chance of rain 20 percent.

Upcountry

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 58 at the visitor center to around 53 at the summit. Southeast winds around 10 mph in the morning becoming light. Chance of rain 50 percent.

Tonight: Partly cloudy with scattered showers. Lows around 45 at the visitor center to around 40 at the summit. East winds around 10 mph in the evening becoming light. Chance of rain 50 percent.

Thanksgiving Day: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs around 58 at the visitor center to around 54 at the summit. Light winds. Chance of rain 50 percent.

East Maui

Today: Mostly cloudy with showers. Highs 78 to 83 near the shore to around 63 near 5000 feet. East winds 10 to 15 mph. Chance of rain 80 percent.

Tonight: Cloudy with showers. Lows 62 to 69 near the shore to 47 to 52 near 5000 feet. East winds 10 to 15 mph. Chance of rain 90 percent.

Thanksgiving Day: Breezy. Occasional showers in the morning, then scattered showers in the afternoon. Highs 79 to 84 near the shore to around 63 near 5000 feet. East winds 10 to 15 mph becoming up to 20 mph in the afternoon. Chance of rain near 100 percent.

Lanai City

Today: Sunny and breezy. Highs 69 to 76. Northeast winds 15 to 20 mph in the morning becoming light.

Tonight: Mostly clear. Lows around 66. Northeast winds around 10 mph in the evening becoming light.

Thanksgiving Day: Sunny and breezy. Isolated showers in the afternoon. Highs 72 to 79. Light winds becoming northeast up to 20 mph in the afternoon. Chance of rain 20 percent.

Kaunakakai

Today: Breezy. Mostly sunny with isolated showers. Highs 73 to 85. East winds 10 to 20 mph. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 58 to 70. East winds around 10 mph in the evening becoming light. Chance of rain 20 percent.

Thanksgiving Day: Sunny. Isolated showers in the morning. Highs 75 to 85. Light winds becoming east up to 15 mph in the afternoon. Chance of rain 20 percent.

Detailed Forecast

Synopsis

Windward areas will be cloudy and showery into Thursday, with showers diminishing thereafter. Light to moderate trade winds will continue to gradually weaken, with light and variable winds Friday and Saturday leading to mostly dry weather. Another front may bring increased showers and winds Sunday or Monday.

Discussion

Mostly cloudy and showery conditions continue to prevail across most of the islands this morning, particularly over windward and mauka areas, and most especially over windward Oahu. Orographically- induced moderate rainfall has been non-stop over the Koolau range through the night, with heavier bursts of rain producing observed rainfall rates near 2 inches per hour. 12-hour rainfall totals are approaching 9″ at the wettest rain gages. In contrast, most leeward areas remain dry, and are in varying levels of drought status, with only .13″ of rain observed at PHNL in the first 3 weeks of November.
The main contributor to the wet windward conditions is remnant frontal moisture that is being advected westward in a light to moderate trade wind flow, with weak low-level convergence supporting the showers. This moisture is E-W oriented near and upstream of the islands; in the form of broken to overcast showery and stable low clouds. Moisture that is fueling much-needed light to moderate rainfall over windward/SE Big Island is associated with a surface trough that is passing S of the area.
An upper-level trough just E of the Big Island will move E, allowing a ridge to build over the area from the W. Meanwhile, surface high pressure to the distant NNE will support light to moderate trade winds through Thursday night. Latest model guidance indicates the increased low-level moisture over the islands will gradually diminish through this time, keeping windward areas cloudy and wet in the short term, but less so Thursday into Friday.
Observations and model guidance both indicate that the recent propensity for sharp troughing aloft to lead to cutoff low formation W of the islands will continue, with another cutoff low developing along 175W this weekend. While this low may not initially impact island weather, the progressive portion of the parent trough will brush just N of the islands this weekend, potentially sending a front over the area. Run-to-run and model-to-model consistency is notably absent, and the details of the forecast become quite murky by the weekend, with lower than normal forecast confidence. Generally speaking, cyclogenesis to the NW will lead to veering and weakening winds Friday and Saturday, leading to a land/sea breeze pattern coincident with a drier airmass, resulting in little rainfall. The low may send a stalling front and increased showers over the islands on Sunday or Monday.
Thereafter, another sharp buckle in the jet has the potential to re- invigorate the closed low aloft to the W while also shifting it eastward closer to the islands. While there is some general agreement in this scenario, the forecast location of the low varies so greatly as to preclude much confidence in the forecast for early next week. Having said that, initial indications are that the stalled frontal moisture could help fuel a wet pattern.

Aviation

Light to moderate easterly flow will continue to push remnant low level moisture towards windward portions of the smaller islands today. This pattern will bring scattered to numerous showers to the windward slopes and coasts, especially for Maui, Molokai, and Oahu. MVFR conditions are likely to accompany this activity with isolated embedded areas of IFR ceilings and visibility. In addition, isolated showers may push over the terrain and onto the leeward slopes.
AIRMET SIERRA remains in effect above 2000 feet for north through east sections of the Big Island and Maui due to tempo mountain obscuration from low clouds and showers. AIRMET SIERRA also remains in effect for IFR ceilings, below 1000 feet, and/or visibility below 3SM in SHRA along north through east facing sections of Oahu.

Marine

Near shore buoys indicate that the current north swell (360-010 degrees) is still producing surf and seas near to just below advisory level. Offshore buoys are now showing a downward trend, thus one can expect surf and seas to trend down through today. Latest ASCAT and altimeter data show that the hurricane force low, roughly 1800 NM NW of the state has a broader and stronger fetch than predicted. Thus the forecast for the extra large, long period (17-20 seconds) northwest (320 degrees) swell has been bumped up a couple of feet and is on schedule to arrive Thursday. This swell will peak Thursday night into Friday, producing dangerously large surf for north and west facing shores that will warrant a High Surf Warning. This swell will also boost seas well into the Small Craft Advisory levels for most waters before slowly easing over the weekend.
Surf along east facing shores will remain rough and choppy for the next day or so, due to the combination of breezy trade winds and the decreasing north swell wrapping into exposed locations. Less choppy conditions are expected later in the week due to decreasing wind speeds, however locations exposed to north swell wrap may still see elevated surf due to the warning level swell mentioned above.
Surf along south facing shores will remain small through the rest of week. The next small, long-period south-southwest swell is expected to fill in over the weekend, keeping surf from going flat.
Moderate to fresh easterly trade winds will persist through Thursday, as a high pressure system remains far northeast of the state. Winds are expected to weaken and veer out of the southeast Friday into Saturday as a front approaches from the northwest. Winds may then shift out the northeast and strengthen into the moderate to locally strong range as the front stalls over the state Sunday.

HFO Watches/Warnings/Advisories

None.

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Data Courtesy of NOAA.gov