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Tropical Weather Discussion
Issued by NWS
Issued by NWS
577 AXPQ20 PGUM 230044 TWDPQ Tropical Weather Discussion National Weather Service Tiyan GU 1044 AM ChST Sun Feb 23 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... None. ...OTHER WEATHER SYSTEMS... TRADE-WIND TROUGHS... There are a few trade-wind troughs seen across the region. The first is seen over Yap Proper, stretching north from near 8N138E to 12N139E. This trough is interacting with a band of trade-wind convergence to produce moderate to deep convection to the west of Yap Proper, with scattered to numerous showers and isolated thunderstorms in a narrow band between 9N and 12N. This trough will move west-southwest over the next few days, exiting the region early in the week. The second trough is seen south of Pohnpei, stretching southeast from near 6N156E to 2N161E. Moderate to deep convection with scattered to numerous showers are seen west of the trough, south of Pohnpei to well south of Weno, Chuuk. Another weak trough is seen just east of this trough, near Kosrae extending south-southeast from near 6N162E to 3N163E. These troughs will continue to move southwest over the next few days, with convection drifting south of the equator. The last trough is found east of the Marshall Islands, extending south-southeast from 12N177E to 6N180. Only patchy clouds and showers are associated with this trough. The trough will continue to move southwest over the coming days with little change in intensity or convection. TRADE-WIND SURGE... A trade-wind surge associated with mid-latitude high pressure stretches eastward from 130E to just west of the Marshall Islands, between 5N and 16N. The region is mostly dry associated with this surge and looks to remain that way over the coming days. The surge is resulting in fresh to strong winds with some areas seeing near-gale to gale force gusts. The surge is expected to weaken over the western portion of the region over the next couple of days and strengthen east as the high pressure responsible drifts eastward. OTHER SYSTEMS... A weakening shear line extends west-southwest across 20N180 to end east of Palau, south of Yap Proper, near 7N137E. Cloudiness with patchy showers are found along the shear line east of 165E. The shear line becomes very diffuse with only patchy cloudiness seen west of 165E. Moderate to fresh winds with strong gusts are found along the the entire length of the shear line. The feature is expected to continue to dissipate over the next few days. Little convection is expected to remain with the shear line. A band of trade-wind convergence is found north of a shear line, extending east-northeast from west of Yap Proper, near 10N133E, across the Marianas to end near 17N152E. Mostly patchy clouds and convection are found along the convergence band, with moderate to deep convection found west of Yap Proper where a weak trade-wind trough is interacting with the convergence. The band of convergence is expected to weaken over the coming days as the shear line to the south of it dissipates. Another band of weak trade-wind convergence is found south of the Marshall Islands over Butaritari and Tarawa atolls. Patchy showers are associated with the band of convergence. A weak trade-wind trough is interacting with the eastern end of the band, but is not producing more than a few showers. The convergence is expected to weaken over the coming days, with decreasing convection. $$ Kleeschulte