Tropical Weather Discussion
Issued by NWS
Issued by NWS
133 AXPQ20 PGUM 190032 TWDPQ Tropical Weather Discussion National Weather Service Tiyan GU 1032 AM ChST Thu Sep 19 2024 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... MONSOON TROUGH... The monsoon trough has weakened and retreated west beyond 130E. TRADE-WIND TROUGHS... Three trade-wind troughs are evident across the region. The first one is seen just east of Yap, extending northward from near 6N140E to 12N140E. Isolated moderate convection is seen north of Yap Proper associated with the trough. This trough is expected to slowly drift west over the next couple of days, being slowed by a surface ridge currently over Palau and Yap State. The second trough is found south of Guam from 1N143E to 12N145E. Moderate to deep convection is associated with the trough south of Guam to well south of Yap. This trough will continue to move west and due to the slowing effect of a surface ridge over Palau and Yap, it is likely the first and second trough will merge just east of Yap Proper. The third trough extends north from near 7N171E to 15N171E. This trough is interacting with the ITCZ to enhance the convergence east of 175E, producing widespread moderate to deep convection. The trough looks to move west, enhancing the ITCZ as it approaches Kosrae and Pohnpei over the coming days. TUTT... A TUTT cell is centered east of the northern CNMI near 20N150E. A trough extends northeast from the cell to beyond 25N near 158E. Another trough extends south from the cell to just east of the Marianas near 15N147E, continuing south to beyond the equator near 150E. Little convection is associated with the TUTT cell, however, moderate to deep convection is present along the trough both northeast and south of the TUTT cell, near Minami Tori Shima to near Tinian and Saipan to between Chuuk and the Marianas. The TUTT and TUTT cell look to drift slowly west over the coming days. OTHER SYSTEMS... A surface high pressure ridge is in place across Yap and Palau producing dry conditions across both Yap State and the Republic of Palau. Bands of convergence to the south, west and north of the ridge are generating widespread deep convection from south to east to well north of Palau. This ridge is expected to continue to weaken over the next couple of days allowing this convection to creep into the region. ...ITCZ... The ITCZ stretches east-northeast from northwest of Kosrae near 6N160E to east of Majuro near 8N173E, then turns east to beyond the Date Line near 6N. A trade-wind trough is seen just east of Majuro as well, moving along the ITCZ. This feature is helping to enhance the convergence east of 175E to beyond the Date Line, producing widespread moderate to deep convection. Otherwise, spotty showers are seen to the west across Kosrae. The ITCZ is expected to drift west over the coming days, with increased convection as the convergence strengthens and surface troughs interact with it. $$ Kleeschulte