


Area Forecast Discussion
Issued by NWS Tiyan, Guam
Issued by NWS Tiyan, Guam
599 FXPQ50 PGUM 060852 AFDGUM Area Forecast Discussion National Weather Service Tiyan GU 652 PM ChST Sat Sep 6 2025 .Marianas Synopsis... Light to gentle northeasterlies prevail across the region. Satellite imagery and Doppler radar indicate slow-moving showers forming in CNMI waters. The buoys show seas are around 3 feet. && .Discussion... A passing broad surface trough interacting with a Tropical Upper Tropospheric Trough (TUTT) cell aloft, is likely to produce patchy showers and some thunderstorms overnight across the region. After, a period of isolated to low-end scattered showers brought by moderate trades is expected to last for much of next week. && .Marine/Surf... Combined seas of around 4 feet, will briefly drop a foot early next week, before going up a few feet once trade and northerly swells, along with localized wind waves, strengthen around midweek. A low risk of rip currents is expected along all reefs of the Marianas for at least the next several days. By midweek, trade and northerly swells are expected to strengthen slightly, allowing surf to increase and potentially introducing a moderate risk of rip currents to north and east facing reefs as early as Tuesday night. && .Eastern Micronesia... The dry trade-wind pattern continues over eastern Micronesia this evening, with only spotty showers seen across the region. This dry pattern looks to continue through the remainder of the weekend. It still looks likely that the Inter-Tropical Convergence Zone (ITCZ) will make a comeback, though it was pushed back a little later than previously expected. Regardless, once the ITCZ reforms, the region is in for another round of wet conditions. Convection will begin to increase Monday with the risk of thunderstorms increasing later in the evening. The ITCZ looks to peak around the middle of next week. Maintained POPs at around 50% for now, though this could change as the location and strength of the ITCZ becomes more clear. This wet pattern will then begin to subside around the end of next week. Little change in the marine forecast. Combined seas of 3 to 4 feet are expected to continue through the middle of next week, then build slightly around the end of the week. Light to gentle trade winds are expected through the coming week. && .Western Micronesia... A broad surface trough is moving away from Chuuk and into eastern Yap State this evening. This feature is expected to continue propagating westward, increasing showers for Yap and Palau around Sunday night through Monday night. Meanwhile, showers are expected to trend down near Weno overnight and Sunday. Then the ITCZ begins to rebuild in eastern Micronesia and much of Chuuk State next week, trending towards wetter weather by Monday night. An ITCZ fragment looks to bring another uptick in showers for Yap and Palau as well, around Wednesday and Thursday. Altimetry data shows benign seas of 2 to 3 feet near Yap and Palau and 3 to 4 feet near Chuuk. Combined seas are expected to increase to 3 to 5 feet around the middle of next week when a pulse of northerly swell moves through the region. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...None. MP...None. Marianas Waters...None. && $$ Marianas: Montvila East Micronesia: Kleeschulte West Micronesia: Cruz