SAIPAN — Partly sunny skies and scattered showers are forecast across Saipan and Tinian on Tuesday, with east winds of 15 to 20 mph and highs around 86 degrees, the National Weather Service in Tiyan, Guam, said in its Tuesday morning zone forecast.
The chance of showers on Tuesday is 30 percent, rising to 40 percent overnight. Mostly cloudy skies with scattered showers and isolated thunderstorms are expected on Tuesday night, with lows near 77 degrees.
The Marianas are sitting in the northern periphery of an unsettled weather pattern tied to tropical disturbance Invest 99W, located in Yap State and embedded in a developing monsoon flow, NWS said. As 99W tracks gradually northwestward, showers are expected to build across converging monsoon and trade-wind patterns, bringing scattered to numerous locally heavy showers and isolated thunderstorms to the Marianas by midweek.
For Wednesday through Thursday, NWS forecasts mostly cloudy skies with scattered locally heavy showers and isolated thunderstorms across Saipan and Tinian. Highs near 86 and lows near 76 are expected, with a 50 percent chance of showers and southeast winds of 15 to 20 mph.
Rota will see a wetter midweek stretch. NWS expects cloudy skies with numerous locally heavy showers and isolated thunderstorms Wednesday and Thursday, with a 70 percent chance of showers and east winds of 15 to 20 mph. Highs near 85 and lows near 75 are forecast.
In coastal waters around Saipan and Tinian, seas are forecast around 5 feet on Tuesday, building to 5 to 7 feet on Wednesday. A longer-period north swell is gradually increasing seas, and a southwest swell is expected to fill in toward the latter half of the week, building seas to 6 to 8 feet by Thursday, NWS said.
Around Rota, southeast winds of 15 knots with gusts to 25 knots are forecast Tuesday night, with seas building to 5 to 7 feet on Wednesday and 6 to 8 feet on Thursday.
Tide schedule for Tanapag Harbor on Saipan: low tide of 0.4 feet at 10:55 a.m. Tuesday, high tide of 1.6 feet at 5:16 p.m. Tuesday, low tide of 1.0 feet at 10:10 p.m. Tuesday, and high tide of 2.2 feet at 4:30 a.m. Wednesday. Tinian Island and Rota Island tides are within roughly 30 minutes of the Saipan schedule.
The forecast was issued at 6 a.m. Tuesday by NWS Tiyan, Guam.
