Moderate to locally breezy trade winds will veer from the southeasterly direction today with a gradual weakening trend for most islands except for Kauai and Niihau, where some increasing winds are expected to develop from this afternoon into the Wednesday as Nolo reaches the closest point of approach to both islands. Clouds and showers will increase into Thursday as Nolo passes to the west pulling up deep tropical moisture along the east side of the storm increasing showers over Niihau, Kauai and Oahu. Nolo moves away to the northwest by this weekend with drier easterly trade winds building back in across the Hawaii Region.
Comparing this mornings satellite imagery to the latest 11 PM HST forecast from the National Hurricane Center, Hurricane Nolo remains on a northerly track, forecast to pass roughly 300 miles west of Kauai. Strong vertical wind shear continues to weaken Nolo, which is forecast to weaken down to tropical storm strength over the next 36 to 48 hours. The main threats with Hurricane Nolo over the next few days will remain the potential for locally heavy rain bands that may develop, and high surf along south facing shores of Kauai County.
Deep tropical moisture riding up the eastern flank of Nolo will increase shower trends later today for Niihau and Kauai, even reaching Oahu by tonight. These showers may become heavy at times and produce higher amounts of rainfall along south and southeast mountain slopes. At this time we are only expecting up to advisory level flooding potential for Kauai County as Nolo passes west of the islands. However, we will continue to closely monitor any developing rain bands for local scale training or terrain anchoring features that could create localized flood warning concerns. Please continue to monitor weather conditions closely through Wednesday as local scale rainfall impacts may rapidly change over time.
Drier and more stable air returns to the western islands by Friday as the upper level ridge builds back in and light to moderate easterly trades return improving weather conditions statewide through Sunday. Brief passing showers are possibly, mainly during the overnight to early morning hours during this time period.
By Monday a weak low pressure system drops into the region and deepens several hundred miles northeast of the Big Island. Northeasterly winds along the western flank of the surface low will drive a convergence cloud band into the Hawaiian Islands from the north early next week. This cloud band will likely bring a several day period of enhanced shower trends to all islands from Monday into Wednesday. These clouds and showers may linger near the Big Island through the end of next week. Higher rainfall amounts will mainly impact the northeastern slopes of Mauna Kea, and include the communities surrounding Hilo.
Moderate to locally breezy trade winds will continue to veer to the southeasterly direction today and continue gradual weakening. Isolated showers are possible across windward and mountain areas tonight into the morning with brief MVFR conditions. Moisture will increase across Kauai and Oahu this afternoon into Wednesday bringing an increased likelihood of showers. Showers are most likely across Kauai starting late morning today with shower chances gradually increasing for Oahu later today into Wednesday.
AIRMET Tango remains in effect for moderate turbulence below 9,000 feet over and immediately downwind of island terrain. This AIRMET will likely be needed at least through Wednesday.
Under the influence of Hurricane Nolo, now located several hundred nautical miles west of the Hawaiian Islands, winds have shifted out of the southeast at moderate to fresh levels for much of the marine area. Winds will be strong and possibly near gale in the coastal zones closer to Nolo, especially as it tracks north tonight and Wednesday. As a result, the Small Craft Advisory remains in effect for the waters around Kauai through Wednesday. Winds remain southeasterly through Friday as Nolo creeps slowly westward away from the islands. Once it begins to accelerate away over the weekend, east to northeasterly trade winds return.
A moderate, medium-period southwest swell originating from Hurricane Nolo will produce elevated surf for south and west facing shores today. For Kauai and Niihau, best positioned to receive swell from the hurricane, some advisory level surf is still possible today along south-facing shores, for which a High Surf Advisory remains in effect. There is considerable uncertainty with how long advisory level surf will linger as Hurricane Nolo lifts north and becomes centered some 250 to 300 nautical miles west of Kauai by Wednesday. On this track, west shore surf will remain elevated, but likely remain below advisory criteria as south-facing shores see a gradual decline in surf through mid-week. For the latter half of the week, south shore surf will be primarily driven by a series of small, long to medium period south swells originating from near New Zealand.
Surf along east shores slowly declines as trades veer southeast and diminish, then return as light to moderate easterlies this weekend. For north-facing shores, the existing small, medium-period swell fades through Wednesday. Multiple rounds of tiny swell originating out of the northwest quadrant will reach north and select west facing exposures next week as the storm track in the vicinity of the Aleutian Islands becomes increasingly active.
High Surf Advisory until 6 PM HST this evening for Kauai South- Kauai Southwest-Niihau.
Small Craft Advisory until 6 PM HST Wednesday for Kauai Channel- Kauai Leeward Waters-Kauai Northwest Waters-Kauai Windward Waters.
