Breezy trades will persist through the weekend, then gradually weaken to moderate speeds by the latter half of the week. Periodic showers will filter in on the trade wind flow, mainly focusing over windward and mauka areas. By next weekend, the background flow may become light enough to support land and sea breeze development.
Radar and satellite imagery shows scattered showers moving over windward and mauka areas with limited spillover into leeward areas across the state this morning. The forecast through the week revolves around gradual fluctuations in trade wind speeds and the timing of minor batches of moisture that will move across the state on the trade wind flow. Guidance remains in good agreement on the surface high to the northeast of the state continuing to drive breezy trades across the state through the rest of today. This high will weaken slightly Monday into Tuesday, then get pushed further northeastward through the rest of the week as a series of lows move across the northern Pacific and a front approaches the region from the northwest. The evolution of the surface high will cause the trades to gradually ease through the week. For the latter half of the week, background winds may be light enough to support land and sea breeze development, bringing afternoon clouds and showers to leeward and interior areas and partial clearing at night.
A high pressure ridge north of the islands will maintain moderate to breezy trade winds over the next several days. Clouds and showers being carried in on the trades will bring periods of MVFR conditions primarily to windward and mauka areas, but winds will be strong enough to carry some showers to leeward areas. Otherwise VFR conditions are expected to prevail. At times an AIRMET for mountain obscuration may be needed.
AIRMET Tango is in effect for mechanical turbulence to the lee of the mountains, and that is expected to continue over the next couple of days with little change in the trade wind speeds expected.
Surface high pressure will remain anchored far northeast of the islands through early this week. The Small Craft Advisory (SCA), currently in effect for all local waters, will be trimmed back to the typically windy waters around Maui and the Big Island later this morning due to a slight weakening in the trades. During the middle of next week, a ridge north of the islands associated with the high will be weakened and depressed southward. As a result, trades will drop further and allow the SCA to be cancelled entirely Tuesday or Wednesday.
Long-period forerunners of the next south swell should begin to show up on the near shore buoys by late this morning or early this afternoon. Energy from this swell is expected to peak late Monday into Tuesday and bump up surf to slightly higher than the June average, but still below advisory criteria. Expect this swell to fade through midweek. A smaller pulse of south- southwest swell is due late Thursday and Friday, and a more significant south- southwest swell is on track to arrive next weekend.
A small west-northwest swell will produce tiny north shore surf through early this week. Rough surf along east- facing shores will remain around seasonal average today, then slowly decline through the middle of next week as trade winds ease.
Small Craft Advisory until 6 AM HST early this morning for Kauai Northwest Waters-Kauai Windward Waters-Kauai Leeward Waters- Kauai Channel-Oahu Windward Waters-Oahu Leeward Waters-Kaiwi Channel-Maui County Windward Waters-Maui County Leeward Waters- Big Island Windward Waters.
Small Craft Advisory until 6 PM HST Monday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters.
