The center of Tropical Storm Nolo has moved out of Hawaii's offshore waters and will travel west over the Papahanaumokuakea Marine National Monument waters the next several days. Bands of showers along Nolo's eastern flank will move up from the south and pass across the islands the next few days with Oahu and Kauai likely picking up the higher rainfall totals. Breezy southeast winds will persist through the day, weaken through late week and then transition back to trades early next week.
At 3 AM HST, Nolo, which was downgraded to a tropical storm last night, was located approximately 320 miles west of Barking Sands Beach, Kauai, and is drifting west this morning. After slowly wobbling westward the next couple of days, Nolo is currently forecast by the National Hurricane Center to accelerate west this weekend. Nolo's far eastern outer bands are providing brief periods of light to locally moderate rain as they quickly pass up from the south over Kauai and Oahu. While the bulk of the heaviest precipitation remains over the nearshore waters west of Niihau and Kauai the next couple of days, Nolo's westerly motion will keep return periods of rain moving up from the south in the forecast over mainly the western third of the state through early Friday. Nuisance flooding of lower lying areas and street ponding may occur, especially across Oahu and Kauai, the next couple of days in the event that rainfall becomes more orientated to the background southeast flow and exhibits more of a training nature. Breezy southeast winds will continue across the state through Thursday. Southeast-east winds will weaken over the weekend as Nolo races away to the west and slackens the gradient back toward the islands.
While Nolo will no longer directly impact the state, rain bands along Nolo's eastern periphery will move across within the southeast flow pattern through Friday. An additional 4 to 6 inches of rain with locally higher amounts near 10 inches, 3 to 5 inches with locally higher amounts within upper terrain, is forecast for Kauai and Oahu, respectively, the next few days. The quick passage of these rain bands over a span of a few days keeps the threat for any widespread significant flooding at bay. Big Island will partially block Maui County from this east southeast flow pattern. This will result in clearer skies over Maui County and leeward Big Island as local land and sea breezes build interior upslope afternoon cloud cover and produce brief showers. East southeasterly winds will gradually weaken this weekend with trades advecting in drier air expected to briefly return early next week.
An upper closed off low located northeast of the state is forecast to sink south early next week. This will push a weak backdoor front into the far eastern waters Monday or Tuesday. This weak boundary stalling in the vicinity of Big Island will disrupt mid to late week trade winds and ultimately produce very light and variable breezes. Relatively drier air behind this northeast boundary may keep dew points just low enough under this very stagnant flow pattern in creating more bearable humidity levels.
Moderate to breezy southeast winds will persist through this afternoon then weaken heading into Thursday as Tropical Storm Nolo gradually slides off to the west, away from the state. Outer rain bands associated with Nolo will bring showers into mainly Kauai and Oahu from the south over the next 24 hours, with Kauai expecting the most coverage. MVFR and even IFR conditions will be possible within these showers.
AIRMET Sierra for mountain obscuration is in effect for Kauai due to the clouds and showers moving over the island from the south, and across windward Oahu as showers persist over the Ko'olaus in the southeast flow. This AIRMET will likely be needed through most of today and may need to be expanded across more portions of Oahu.
AIRMET Tango is in effect for low level turbulence west through north of the island terrain over Kauai. This AIRMET may be needed through most of today before the low level wind speeds decrease as Nolo pushes further west.
Moderate to fresh south to southeast winds prevail for most areas as Tropical Storm Nolo slowly drifts westward away from the Hawaiian Islands. For waters surrounding Kauai, stronger southerly winds will continue through the day. Gentle to fresh east to southeast winds prevail across all waters by Thursday.
The moderate, medium period west to southwest swell originating from Nolo will continue for Niihau and Kauai today. A small background south swell continues for other islands. The next small boost in south swell energy will arrive early next week Monday and Tuesday.
Surf along other shores will remain small until moderate trades return early next week providing a slight boost to east facing shores. Multiple rounds of tiny northwest swell energy will reach north and west facing shores into early next week as the storms tracking near the Aleutian Islands becomes increasingly active.
Small Craft Advisory until 6 PM HST this evening for Kauai Channel-Kauai Leeward Waters-Kauai Northwest Waters-Kauai Windward Waters.
