textproduct: Honolulu

SYNOPSIS

Moderate to locally breezy trade winds will persist into the upcoming weekend. Bands of low clouds and showers will be at times be carried in on the trades, focused primarily over windward and mauka areas during the overnight and early morning hours. Another such band is expected to reach the islands Tuesday night. Additionally, humidity levels will rise, bringing muggier conditions across the island chain through the middle of this week.

DISCUSSION

No major changes to the forecast with the afternoon package. The most recent moisture area moved through the islands this morning, bringing some clouds and showers to the region. This afternoon, more typical clouds and showers are being carried in on the trade wind flow.

A 1038 mb high pressure system remains far north-northeast of the islands this afternoon. This high is expected to remain nearly stationary over the next couple of days, and then slowly move to the west, weakening a little as it moves due north of the islands during the second half of the week. The resultant pressure gradient will maintain moderate to locally breezy trade winds into the weekend.

Clouds and showers will ride in on the trades, focusing the wetter weather over the windward sides of the islands. However at times, these typical showers will be carried to leeward areas. As is typical in this pattern, afternoon clouds and showers are possible over the kona slopes of the Big Island. Another noticeable batch of moisture, similar to what moved through the islands last night and this morning, is about 360 miles northeast of the islands this afternoon, and this will likely move into the islands tomorrow night.

Dewpoints have reached into the lower 70s today, which will make it feel more muggy than normal across the state. These elevated dewpoints are expected to continue into the middle of the week, until dropping back into the upper 60s late Thursday.

AVIATION

Drier air moving in this afternoon will reduce clouds and showers tonight. Cloud build ups across the Big Island due to this moisture and daytime heating will dissipate after sunset. For now, AIRMET Sierra remains in effect for tempo mountain obscuration above 2000 feet for windward and southeast slopes through 04Z today.

AIRMET Tango is also posted for tempo moderate leeward turbulence below 8000 feet for all islands due to the breezy trade winds. Expect this AIRMET to continue at least for the next couple of days.

MARINE

An area of surface high pressure will remain centered well north of the Hawaiian Islands this week and help drive moderate to fresh trades trades across the region. The Small Craft Advisory (SCA) has been trimmed back to the typical windy waters around Maui County and the Big Island with trade winds easing slightly overnight into Tuesday. However, the SCA advisory will likely need to be extended for these areas through much of this week with the persistent trades.

The current moderate, long-period south swell (nearly 3 feet, 15 seconds on offshore buoys) will begin to slowly fade tonight and continue to decline through midweek, leading to decreasing south and west shore surf through Wednesday. A small bump in surf along south-facing shores is possible Thursday into Friday with the arrival of a small, long-period south swell, but another larger long-period south swell energy pulse should arrive by late Saturday.

Surf along east-facing shores will remain rough and choppy through the week with moderate to fresh trades in place. Nearly flat surf heights will persist along north facing shores.

HFO WATCHES/WARNINGS/ADVISORIES

Small Craft Advisory until 6 PM HST Tuesday for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters- Maalaea Bay-Pailolo Channel.