Tropical Weather Discussion
Issued by NWS
Issued by NWS
525 AXPQ20 PGUM 020051 TWDPQ Tropical Weather Discussion National Weather Service Tiyan GU 1051 AM ChST Sun Nov 2 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 CYCLONES... What was Invest 98W is now Tropical Storm 31W, Kalmaegi. Kalmaegi is centered north of Palau, northwest of Yap Proper near 10.7N 135.1E, moving west-northwest at 13 mph. Widespread showers and isolated thunderstorms are found up to 310 miles mainly west through north of the center. A small band of scattered showers and isolated thunderstorms is seen farther north in a weak feeder band between 16N and 17N from 135E to 138E. Kalmaegi is expected to strengthen over the next couple of days as it continues to move west-northwest, possibly becoming a typhoon within the next 24 hours. For more information on TS Kalmaegi, please refer to bulletins issued by the Joint Typhoon Warning Center under WMO header WTPN31 PGTW and by the National Weather Service under WMO header WTPQ31 PGUM. TROPICAL AND MONSOON DISTURBANCES... Invest 99W is now more of an open trough and no longer suspect for development into a significant tropical cyclone. Only partly cloudy skies and spotty showers are associated with 99W. The area will continue to be monitored over the next 24 hours for any additional disturbances. ...OTHER WEATHER SYSTEMS... MONSOON TROUGH... The monsoon trough extends east-northeast through 9N130E to TS Kalmaegi, then continues east to end over Chuuk Lagoon near 7N152E. Scattered showers are seen in the monsoon flow south of the trough, south of Palau and Yap Proper, near Ngulu. Farther east, scattered to numerous showers and isolated thunderstorms are found south of the trough across Chuuk and eastern Yap States. Convection is being enhanced in the monsoon flow by strong upper-level divergence. The monsoon trough is expected to strengthen a bit and drift slightly north as TS Kalmaegi continues to move west-northwest over the next couple of days. TRADE-WIND TROUGHS... A weak trade-wind trough is seen northeast of Weno, Chuuk extending north from near 9N157E to end near 14N157E. Upper-level divergence southeast of the TUTT is interacting with this trough to produce numerous showers and isolated thunderstorms well east of the Marianas. This trough will continue to move west over the next few days while it slowly weakens. A second trade-wind trough extends northeast from south-southwest of Pohnpei near 3N157E to end near 10N165E. This trough is interacting with divergence associated with the TUTT to generate scattered to numerous showers and isolated thunderstorms across Pohnpei State into eastern Chuuk State. The trough will continue to move slowly west- northwest over the next few days as it slowly weakens. Another trough is seen east of Majuro, extending northeast from a weakening circulation centered near 5N173E to end near 11N180. Converging winds east of the trough are producing scattered showers and isolated thunderstorms along and east of the trough. This trough looks to move west as the circulation continues to weaken, bringing increased convection into the Marshall Islands. TRADE-WIND SURGE... A monsoon surge is seen between 15N and 25N, east of 165E to beyond the Date Line. Scattered showers are seen within the surge from 165E to 174E, with numerous showers and isolated thunderstorms found east of 174E to beyond the Date Line where upper-level divergence is enhancing the convection. The surge is also resulting in increased seas, with altimetry showing combined seas between 10 and 12 feet within the surge. The trade-wind surge is expected to begin to subside and retreat eastward over the next few days. TUTT... The TUTT enters the area near 25N166E, extending southwest through a cell centered near 18N160E to end northwest of Weno, Chuuk near 9N151E. Strong divergence southeast of the TUTT is interacting with a trade-wind trough east of Pohnpei to produce scattered to numerous showers and isolated thunderstorms across Pohnpei into eastern Chuuk State. The TUTT and TUTT cell look to continue to drift west over the coming days with little change in intensity. $$ Kleeschulte