FXPQ50 PGUM 200725 AFDGUM Area Forecast Discussion National Weather Service Tiyan GU 525 PM ChST Wed May 20 2026 .Marianas Synopsis... Isolated showers will continue through tonight before briefly increasing to scattered Thursday afternoon through evening. Combined seas of 6 to 8 feet and a high risk of rip currents along east- facing reefs continue through Thursday afternoon before gradually subsiding. Models continue to trend towards a wetter weekend due to the potential of a tropical disturbance tracking through the Marianas. && .Discussion... Satellite imagery depicts a fairly dry trade-wind regime, although some patches of moderate showers and mostly cloudy skies have been intermittent across the Marianas throughout the day. This pattern is expected to continue, increasing from isolated to scattered showers as a trade-wind trough tracks through the region beginning with Guam as early as Thursday afternoon followed by Rota, Tinian, and Saipan through the evening. Beyond Thursday, the region may experience a brief return to isolated showers and winds from 15 to 20 miles per hour on Friday, before an uptick in shower coverage and a slight chance of thunderstorms is possible starting Saturday. Model guidance continues to portray a potential disturbance developing in central Micronesia and tracking north-northwest through the Marianas early next week. Confidence continues to grow in wetter impacts across the region starting Saturday through the holiday weekend, but the disturbance itself has yet to be realized as development is still in its earliest stages. We will continue to monitor and communicate conditions as the weekend nears. && .Marine... Combined seas of 6 to 8 feet will prevail across the region through Thursday afternoon as the easterly trade swell continues to elevate sea heights. Buoy and altimetry data supports swells capable of producing surf up to 9 feet, so, there is a high risk of rip currents along east-facing reefs and is expected to continue through Thursday afternoon before dropping to moderate Thursday night. A moderate risk of rip currents is also prevalent along north-facing reefs and will continue over the next several days. Sea heights will start to subside Thursday night and may hover 4 to 6 feet throughout the weekend. && .Eastern Micronesia... The leading edge of the Near-Equatorial Trough (NET) interacting with the Intertropical Convergence Zone (ITCZ) remains the primary driver for weather across eastern Micronesia. Extensive heavy showers and some thunderstorms are expected to continue at Pohnpei through Thursday night and at Kosrae through Thursday, followed by a brief and slight decrease in shower coverage. Then, showers and thunderstorms will again peak during the weekend as an ITCZ surge is expected to backbuild across the Marshalls as trade-wind flow continues to bulk against the NET and associated developing disturbance, followed by a disintegration in the southeasterly component that will push the ITCZ back toward the central Pacific by early next week. This backbuilding will bring gusty, heavy and intense showers to Majuro before the weekend, with some near gale- force gusts expected near the heaviest showers. As the aforementioned disturbance heads further west and/or northwest, showers and thunderstorms will return to a more patchy coverage across the region, but a dry spell is not likely to develop as the primary convergence zone remains across all three islands. Combined seas of 4 to 6 feet near Pohnpei and Kosrae, and 5 to 7 feet near Majuro, are expected to taper down a foot over the coming days, to then remain as such for the rest of the forecast period as trade swell remains moderate. && .Western Micronesia... Satellite observations show isolated to scattered showers across the region. Altimetry shows combined seas between 4 and 7 feet. A relative lull is ongoing across western Micronesia. For Palau and Yap, weather conditions look to be in and out of an active phase through much of the week with 30 to 40 percent PoPs through Saturday. As we head into next week, a monsoon tail looks to develop across the region, bringing increased shower activity. Additionally, a tropical disturbance may reside within or just north of the region next week. This would help enhance rainfall across Palau and Yap in the extended range. Uncertainty remains high on the location or strength of any potential tropical disturbance next week, but there is medium confidence for increased rainfall, either due to direct impacts of a tropical disturbance or from the monsoon tail that forms south of it. Across Chuuk State, initial conditions are relatively quiet with scattered showers. Shower coverage looks to increase to numerous tomorrow due to the convergence from the monsoon-like trough to the west, the NET to the south, and the ITCZ to the east meets across Chuuk State. As this convergence comes together, low-level vorticity will begin to concentrate over Chuuk State as the early stages of a tropical disturbance begins to form. Widespread locally heavy rainfall is expected Friday night through Saturday night for Chuuk, as the tropical disturbance shifts west and shifts the inflow band over Chuuk. Showers and thunderstorm coverage will slowly decrease starting Sunday, but an active pattern looks to remain. Marine conditions are between 4 and 7 feet and look to stay benign through the week. Some choppy seas will be possible across Chuuk State near heavier showers. As the monsoon tail intensifies next week, seas look to rise near Palau and Yap. Those with marine interest across Palau and Yap should continue to monitor the forecast to remain up to date. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...High Rip Current Risk through Thursday afternoon for GUZ001. MP...High Rip Current Risk through Thursday afternoon for MPZ001>003. Marianas Waters...None. && $$ Marianas: Mesa East Micronesia: Montvila West Micronesia: Williams