textproduct: Honolulu

SYNOPSIS

Strong high pressure far north of the state will continue to produce breezy trades through the weekend and well into next week. An increase in moisture will bring enhanced showers to windward and mauka locations Saturday night into Sunday morning. The next plume of moisture could then arrive by the middle of next week, otherwise a typical summertime trade wind shower distribution is expected.

DISCUSSION

Radar and satellite show partly to mostly cloudy skies with showers focused mainly windward and mauka. The highest concentration of showers early this afternoon has been over Kauai and the Big Island. Winds were breezy, averaging 10-20 mph sustained with gusts 25 to 35 mph.

A strong upper level ridge will remain anchored to our north over the next week, helping to keep a surface high in place. Winds rotating clockwise around this surface high will then keep the trades blowing, bringing a rather typical summer pattern. Showers will continue, mainly windward and mauka, and most numerous at night. One noticeable increase in low level moisture will arrive Sunday, resulting in an increase in both the coverage and strength of showers. This should also increase the number that make it over to leeward areas. There may be additional periods of increased moisture next week, but details are not available yet.

The tropics are showing signs of life not too far away, but at this time no systems are forecast to impact the state. Longer range ensembles indicate that the last two weeks of the month may bring an environment supportive of further development, but it is way too early to have any details. However, now would be a good time to make sure you are prepared for what could prove to be an active El Nino tropical storm season.

AVIATION

Moderate to breezy trades continue across the state, with pockets of embedded light to moderate shower activity expected to impact windward sites at times, occasionally spilling over into leeward areas. Expect VFR conditions to prevail across most locations, with occasional localized MVFR/IFR conditions in association with low clouds and shower activity.

AIRMET Sierra is in effect for mountain obscuration above 2500 feet for windward of all islands. This is expected to persist throughout the period as shower activity continues, even if showers prove to be intermittent at times.

AIRMET Tango remains in effect for moderate low-level turbulence over and downwind of terrain for all islands. This AIRMET will likely continue as this ongoing trade wind pattern persists.

MARINE

Strong high pressure centered north of the state will remain nearly stationary through the forecast period. Fresh to strong trade winds are expected through Saturday afternoon. The Small Craft Advisory (SCA) has been extended through Saturday for all Hawaiian waters. Trades will remain fresh to strong through the weekend so the SCA may need to be extended through Sunday before getting scaled back to the windier waters and channels around Maui County and the Big Island.

The current small medium-period south-southwest (190-200 degrees) swell will plateau through Saturday just below the summer average. A small to moderate, long- period southwest swell (220 degrees) is expected to fill in late Saturday through Monday, which can elevate surf through early next week.

Surf along east-facing shores will remain rough and choppy through the forecast period as fresh to strong trades hold. A series of small, moderate period west (270 to 280 degrees) swells are expected to arrive this evening and hold into early next week, sourced from Typhoon Bavi in the far western Pacific. Surf along north- facing shores is expected to remain flat to tiny with no significant swells forecast from the north or northwest.

Looking ahead, higher than normal high tides will be possible beginning during the latter half of this weekend. Interests immediately along the coasts in low-lying or vulnerable areas should continue to monitor forecasts for possible coastal flooding due to the King Tides from Sunday through the first half of next week.

HFO WATCHES/WARNINGS/ADVISORIES

Small Craft Advisory until 6 PM HST Saturday for Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters- Big Island Windward Waters-Kaiwi Channel-Kauai Channel-Kauai Leeward Waters-Kauai Northwest Waters-Kauai Windward Waters- Maalaea Bay-Maui County Leeward Waters-Maui County Windward Waters-Oahu Leeward Waters-Oahu Windward Waters-Pailolo Channel.