000 AXPZ20 KNHC 170948 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon Jun 17 2024 Tropical Weather Discussion for the eastern Pacific Ocean from 03.4S to 30N, east of 120W including the Gulf of California, and from the Equator to 30N, between 120W and 140W. The following information is based on satellite imagery, weather observations, radar, and meteorological analysis. Based on 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Central America and southern Mexico Heavy Rainfall Event: A broad area of low pressure persists over northern Central America and southern Mexico. This weather pattern, known as a Central American Gyre (CAG), a southwest flow draws abundant moisture from the Pacific Ocean into the coastal terrain of Central America and southern Mexico. This pattern will persist at least through midweek, enhancing heavy rainfall and strong thunderstorms. This can cause life-threatening conditions that include flooding and mudslides. Numerous heavy showers and thunderstorms have already impacted the coasts of Guatemala and the Mexican state of Chiapas. The main areas impacted by the heavy rainfall will be northwest Nicaragua, southwest Honduras, El Salvador, coastal sections of Guatemala and the Mexican state of Chiapas. Additionally, dangerous surf conditions will impact these coastal areas through the next few days. Please refer to your local meteorological and emergency management office bulletins for more detailed information. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A monsoon trough extends southwestward from the coast of Guerrero State in Mexico through 13N115W to 07N128W. An ITCZ continues westward from 07N128W to beyond 07N140W. Numerous moderate to scattered strong convection is noted south of the monsoon trough in the offshore waters of Chiapas and Oaxaca States of Mexico from 13N to 17N between 90W and 100W. Scattered moderated convection is seen farther west from 09N to 12N between 101W and 112W...and near the ITCZ from 05N to 08N west of 137W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Refer to the Special Features section above for details on heavy rainfall. Refer to the ITCZ/Monsoon Trough section above for convection in the area. A surface ridge extends southeastward from a 1027 mb high near 32N142W to west of Baja California Sur near 21N117W. Fresh with locally strong NW to N winds and seas of 7 to 10 ft exist west of Baja California Norte, while moderate to fresh NW to N winds with 6 to 8 ft seas are present west of Baja California Sur. Moderate to locally fresh W to NW winds and seas at 5 to 7 ft are seen across the offshore waters of central Mexico. Gentle to moderate S to SW winds and 2 to 4 ft seas dominate the Gulf of California. Moderate to fresh with locally strong WSW to W winds and seas of 7 to 9 ft are found offshore of Oaxaca and Chiapas States of southern Mexico. For the forecast, fresh to strong SW to W winds, rough to very rough seas, and numerous heavy showers and strong thunderstorms will impact the offshore waters of southern Mexico through Fri, primarily off Chiapas, Oaxaca and southeastern Guerrero. This inclement weather is associated with a broad area of low pressure over the region known as the Central American Gyre. Dangerous surf is also anticipated through Thu along the coastal areas of this region. Farther north, fresh to strong NW winds and very rough seas will persist off Baja California Norte through Tue morning, primarily beyond 120 nm offshore. Large swell of 8 to 10 ft will linger in these waters mainly north of Cabo San Lazaro through this evening before gradually subsiding through Tue night. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Refer to the Special Features section above for details on heavy rainfall. Fresh to strong SW to W monsoonal winds along with seas at 8 to 11 ft, and widely scattered moderate convection are evident at the offshore waters of Guatemala and El Salvador. Moderate to fresh SW winds with 6 to 9 ft seas and isolated thunderstorms are occurring offshore of Nicaragua. Near the Galapagos Islands and west of Ecuador, gentle to moderate southerly winds and seas at 6 to 8 ft are noted. Mainly gentle southerly winds and 4 to 6 ft seas prevail for the rest of the offshore waters. For the forecast, fresh to strong SW to W winds, rough to very rough seas and numerous heavy showers and strong thunderstorms will persist through Fri across the offshore waters of northern Central America, associated with a broad area of low pressure known as a Central American Gyre. Dangerous surf is also anticipated through Thu along the coastal areas of this region. Farther south, rough seas in moderate to large southerly swell will continue near the Galapagos Islands and offshore of Ecuador through Tue night. ...REMAINDER OF THE AREA... Refer to the ITCZ/Monsoon Trough section for convection in the region. Broad ridging associated with a 1027 mb high near 32N142W dominates the waters north of the ITCZ and monsoon trough. North of 20N and west of 110W, moderate to fresh N to NE winds and 6 to 9 ft seas in large NW to N swell are present, except near 29N122W where winds are fresh to strong with 9 to 11 ft seas. From the ITCZ and monsoon trough to 20N and west of 110W, winds are gentle to moderate with 5 to 7 ft seas in mixed swell. East of 110W, SW to W winds are moderate to fresh with 6 to 9 ft seas in large SW swell. South of 07N, southerly winds are mostly gentle to moderate and seas are 5 to 7 ft seas in moderate southerly swell. For the forecast, the high pressure and related ridge will gradually weaken starting midweek, which should allow winds and seas north of 20N to slowly subside after midweek. will dominate waters west of 120W into the weekend. East of 110W, SW to W winds are going to increase to between fresh to strong with seas building to between 8 and 10 ft by Tue. Scattered moderate convection is expected to continue near the monsoon trough through at least midweek. Seas of 7 to 8 ft will hover around 03S west of the Galapagos Islands through Fri. $$ Chan