


Tropical Weather Discussion
Issued by NWS
Issued by NWS
782 AXPQ20 PGUM 030114 TWDPQ Tropical Weather Discussion National Weather Service Tiyan GU 1114 AM ChST Sun Aug 3 2025 Tropical Weather Discussion for the Western North Pacific between the Equator and 25N from 130E to 180. The following information is based on recent satellite imagery/data, weather observations, radar, and meteorological analysis. ...SPECIAL FEATURES... TROPICAL AND MONSOON DISTURBANCES... The remnants of Iona, that crossed the Date Line yesterday evening and quickly weakened below TD strength, is centered near 17.3N 176.5E. Convection is seen on the periphery of the circulation, where divergence associated with the TUTT is interacting with it. Iona remnants will continue to move northwest with no strengthening expected over the next few days. Invest 94W, previously located near 6N160E, no longer has an identifiable low-level circulation center. Therefore, Invest 94W is expected to dissipate within the next few hours. ...OTHER WEATHER SYSTEMS... TRADE-WIND AND SURFACE TROUGHS... A trade-wind trough is found east of Weno, Chuuk, extending north- northeast from near 5N152E to end near 11N155E. Scattered showers are found along this trough, with isolated thunderstorms possible. The trough will continue moving west toward Weno. The next trade-wind trough is seen east of the Marshall Islands, extending northeast from near 4N175E to near 14N180. Scattered showers and isolated thunderstorms are found along the trough axis. This trough will continue to move west over the coming days. A surface trough is found in the area where Invest 94W was previously located. It extends north-northeast from near EQ155E to near 9N160E, then turns east-northeast to end near 11N164E. Moderate convection is found along, west and south of the trough in the region of the strongest low-level convergence. The trough is expected to continue moving northwest, approaching the Marianas in the next few days. A surface trough is seen west of the Marianas, extending south from near 18N142E to a weak circulation centered west of Guam near 14N142E, then turns southwest to end south of Yap Proper near 8N138E. Numerous showers and isolated thunderstorms are found north of Yap Proper in an area of enhanced convergence north of a surface ridge over Yap. The trough and associated convergence and convection will drift west over the coming days. Another weak trough extends east- southeast from the circulation to end near 10N149E. Convergence near and north of this trough is generating scattered showers and isolated thunderstorms to the south of Guam. As the circulation drifts west, the rough will be pulled west as well as it moves northward, rotating around the circulation. TUTT... The TUTT extends southwest, entering the AOR near 25N179E, then turns south-southeast near 20N175E. It passes through a TUTT cell centered near 14N176E to end near 1N180. The TUTT and TUTT cell are enhancing convection associated with the remnants of Iona. The TUTT is expected to remain quasi-stationary over the next few days. OTHER SYSTEMS... A band of strong convergence is found well south of Palau, extending east-southeast from near 2N130E to beyond the equator near 137E. Scattered showers and thunderstorms along this band of convergence to south of the equator. The convergence is expected to drift north as a high pressure ridge, centered near 14N133E, drifts northwest over the coming days. This ridge is promoting fair weather across Palau. Another high pressure ridge is found just west of Weno, Chuuk, curving southwest then northwest toward Yap Proper. This feature is promoting fair weather across most of Chuuk State and Yap State, south of Yap Proper. ...ITCZ... The ITCZ has weakened significantly and is now a band of convergence oriented north to south. It extends south from near 10N166E to near 1N166E. Isolated showers are found with the band of convergence. It is expected to continue to weaken over the next couple of days as it drifts west. $$ Kleeschulte