Area Forecast Discussion
Issued by NWS Tiyan, Guam
Issued by NWS Tiyan, Guam
182 FXPQ50 PGUM 100613 AFDGUM Area Forecast Discussion National Weather Service Tiyan GU Issued by National Weather Service Honolulu HI 413 PM ChST Thu Jul 10 2025 .Marianas Synopsis... Satellite observations show mainly scattered mid and high clouds with a few smaller convective lower clouds in vicinity of the islands. Larger areas of thunderstorms remain outside of the coastal waters to both the west and the east. Light southeasterly trade winds remain in place with the surface high far away to the northeast of the area. && .Discussion... The Marianas are experiencing a relatively quiet weather pattern between converging monsoon flows and trade winds. Expect a mix of isolated to scattered showers and isolated thunderstorms over the next couple of days, with a potential for heavier showers over the weekend and into next week. && .Marine... Sea state and surf will remain steady, but with a slight increase in trade swell and sea height, especially for east facing reefs over the weekend. Both the GFS and ECMWF show an increase in combined seas this weekend emanating from an easterly swell. Seas only look to rise 1 to 2 feet, but the increase in swell is expected to lead to a moderate risk for rip currents along east facing reefs this weekend. && .Eastern Micronesia... Eastern Micronesia will remain under the influence of the Inter- Tropical Convergence Zone and trade-wind troughs, leading to a occasionally wet end of the week. Models indicate a broad sustained increase in trades across eastern Micronesia tonight through the next few days, bringing moderate to fresh winds throughout the region. This will lead to increases in trade swell and sea height, and subsequently an increase in surf, mainly for east-facing reefs. For Kosrae, surf is expected to remain at hazardous levels of 8 ft until around Sunday, and the High Surf Advisory has been continued. Earlier buoy data off Kosrae`s southern shoreline showed combined seas of around 4 to 6 feet, which are expected to increase another foot or so through Friday. Earlier altimetry passes showed combined seas of 5 to 7 feet between Kosrae and Majuro, and 6 to 8 feet east of Majuro. Seas will continue to rise tonight through the next day or two, but then trade winds and associated wind waves and swell are expected to relax early next week. && .Western Micronesia... Continued unsettled weather due to a convectively active southern flank of the monsoon trough into early next week. Expect significant pulses of showers and thunderstorms over the next several days, with peak potential over the weekend, especially for Palau. Consistent higher rainfall rates next week could lead to a threat of mudslides, and this potential will need to be reassessed over the coming weekend. A primarily small southwest swell will dominate, with a persistent east swell mixing in by Saturday. && .Aviation... VFR conditions. Isolated heavy showers can quickly drop conditions to MVFR or IFR CIGS and/or VIS, which would be confined to less than an hour temporarily. && $$ Marianas: Brenchley East Micronesia: Brenchley West Micronesia/Aviation: Brenchley