Tropical Weather Discussion
Issued by NWS
Issued by NWS
861 AXPQ20 PGUM 040050 TWDPQ Tropical Weather Discussion National Weather Service Tiyan GU 1050 AM ChST Sun Oct 4 2026 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... Typhoon Choi-wan continues its slow departure from the Marianas, with the 7AM ChST position placing the center near 21.2N 146.8E. Maximum sustained winds have increased to 110 mph, and further strengthening into a category 3 typhoon is expected by tonight. It`s currently moving northeast at 9 mph, but a turn more to the north is expected as it treks across the west central Pacific. Convection associated with its outer circulation continues to affect the northern-most portions of the CNMI, and this should continue through Monday morning. For more information please refer to bulletins from the Joint Typhoon Warning Center under WMO header WTPN32 PGTW and from the National Weather Service under WMO header WTPQ32 PGUM. TROPICAL AND MONSOON DISTURBANCES... Invest 94W continues to organize, as it`s done so fairly rapidly since yesterday, and it`s now rated as "Medium" from JTWC (the Joint Typhoon Warning Center). This means tropical cyclone development is expected, but beyond 24 hours. This system is in a favorable region for development, characterized by low vertical wind shear and warm SSTs (Sea Surface Temperatures), with a nearby Majuro buoy showing a water temperature of 86F. Convection with 94W continues to try to wrap around the LLCC (Low-Level Circulation Center), indicating it`s trying to organize/strengthen as well. We expect this process to continue the next 24 to 48 hours, with continued organization and increasing convective coverage, before the system starts to left off to the north-northwest. ...OTHER WEATHER SYSTEMS... MONSOON TROUGH... Today the monsoon trough enters the AOR at 17N130E and extends east-northeast to Typhoon Choi-wan. The trough then southeast through a col northwest of Pohnpei near 10N155E. It then turns east to 94W before exiting the AOR at 10N180. Similar to the past few months, west to southwest cross-equatorial monsoon flow is found south of the trough axis, with convection tied to within 200 miles of the trough axis. We expect this pattern to continue the next few days with Choi-wan and 94W lifting the trough axis north some as they continue moving north and north-northwest respectively. However, Hurricane Nolo looks to continue heading west towards Wake Island, entering the AOR sometime next week as a typhoon (same thing as a hurricane, we just use typhoon in the WestPac - Western Pacific), which will complicate the pattern. $$ Doll