000 AXPZ20 KNHC 180353 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Tue Jun 18 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...SPECIAL FEATURES... Central America and southern Mexico Heavy Rainfall Event: The broad area of low pressure over SE Mexico and western Central America has moved into the Bay of Campeche and has been designated as Potential Tropical Cyclone One (PTC One) in the Atlantic basin. The broad system draws abundant moisture from the Pacific Ocean into the coastal terrain of Central America and southern Mexico. This pattern will continue at least through late week, 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 from the northwest coast of Oaxaca State of Mexico through 08N120W to 07N141W. There is no ITCZ east of 140W. Numerous moderate to scattered strong convection is observed from 14N to 17N between 93W and 98W. Scattered moderate convection is noted from 10N to 13N between 90W and 106W, and from 06N to 11N between 111W and 123W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Refer to the Special Features section above for details on heavy rainfall. The persistent enhanced SW-W flow south of southern Mexico associated with PTC One results in fresh to near gale-force SW winds. This was confirmed by a recent scatterometer (ASCAT) satellite pass. The strongest winds are likely associated with the strong convection in the area. Seas in these waters are 8-11 ft. A 1026 mb high pressure system over the North Pacific dominates the remainder of the area. The pressure gradient between the aforementioned ridge and lower pressures due a low pressure off southern California result in fresh to strong northerly winds west of Guadalupe Island, as seen by ASCAT. Northerly swell is producing seas of 9-11 ft in the area described. Elsewhere in the Baja California offshore waters, moderate or weaker winds and seas of 6-9 ft are prevalent. The scatterometer data also showed moderate to locally fresh southerly winds and seas of 2-5 ft in the Gulf of California. In the remainder of the Mexican offshore waters, moderate or weaker winds and moderate seas are prevalent. 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 States. Dangerous surf is also anticipated through Thu along the coastal areas of this region. Farther north, fresh to locally strong NW winds and very rough seas will persist off Baja California Norte through Tue morning, primarily beyond 120 nm offshore. NW swell in these waters mainly north of Cabo San Lazaro will gradually subside through Tue night. From Wed evening through Fri morning, fresh to strong NW winds and rough seas should develop near Baja California Sur, including waters near Cabo San Lucas as pressure gradient increases. ...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. Potential Tropical Cyclone One, centered in the Bay of Campeche, continues to induce a strong monsoonal flow, resulting in fresh to locally near gale-force SW to W winds along with seas at 8 to 11 ft. Scattered showers and thunderstorms are evident in the offshore waters of Guatemala and El Salvador. Moderate to fresh SW winds with 5-8 ft seas and isolated thunderstorms are occurring offshore of Nicaragua. Moderate to locally fresh southerly winds and seas of 6-8 ft are occurring south of 01N. Elsewhere, moderate or weaker winds and slight to moderate seas prevail. 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. 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. The enhanced monsoon flow supports fresh to strong S-SW winds south of the monsoon trough to 06N and east of 120W, as shown by a recent ASCAT pass. Seas in these waters are 7-10 ft. A 1026 mb high pressure system near 31N145W dominates the waters north of the ITCZ and monsoon trough. The pressure gradient between this ridge and lower pressures off southern California result in fresh to strong northerly winds and seas of 9-11 ft north of 27N and east of 127W. Moderate to locally fresh N-NE winds and seas of 6-9 ft are found north of 15N and west of 115W. Elsewhere, moderate or weaker winds and moderate seas prevail. 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 8-11 ft by Tue. Scattered moderate convection is expected to continue near the monsoon trough through at least midweek. Seas of 7-8 ft will hover around 03S west of the Galapagos Islands through Fri. $$ Chan