000 AXPZ20 KNHC 131602 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Thu Jun 13 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 1200 UTC surface analysis and satellite imagery through 1530 UTC. ...SPECIAL FEATURES... A Central American Gyre (CAG) is rapidly developing. Heavy rainfall is already occurring, and the main event is not at its peak yet. The persistent moist onshore flow over portions of Guatemala, Chiapas, Honduras, and El Salvador will favor days of intermittent rounds of heavy precipitation. Excessive rainfall is also expected over Costa Rica and Panama, from Friday through the weekend, producing 8-12 inches of rain across these areas. This scenario is common during the developing of La Nina. Please refer to your local meteorological office bulettins for more detailed information. ...TROPICAL WAVES... A tropical wave is in the far eastern portion of the tropical eastern Pacific, with axis along 81W from Panama to near 03N, moving west at 5 to 10 kt. Scattered moderate isolated strong convection is noted N of 02N and E of 82W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 12N87W to 16N96W to 08N126W. The ITCZ extends from 08N126W to 09N140W. Scattered moderate and isolated strong convection is from 05N to 16N between 90W and 106W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... High pressure centered well NE of Hawaii extends a ridge southeastward to just W of the Revillagigedo Islands. This pattern supports moderate to fresh NW to N winds across the Baja offshore waters. Seas are generally 5 to 7 ft in NW swell. A surface trough extends across the Gulf of California along 110W to south of Baja California. Moderate winds are on either side of the trough in the central and southern Gulf of California, with light and variable winds in the northern Gulf of California. Seas are 1 to 3 ft in the Gulf of California, except to 4 ft near the entrance. Gentle winds dominate the remainder of the Mexican offshore waters, except for S of 14N, where the monsoon trough has lift N to. S of the trough, moderate to locally fresh SW winds prevail. Seas through the waters S of Baja California are 4 to 7 ft in mixed SW and NW swell. Thunderstorms persist across the waters south of 17N and east of 105W. North of 15N away from any convection and extending to offshore Jalisco, smoke from agricultural fires may be restricting visibility somewhat over area waters. For the forecast, troughing will extend from the Gulf of California to near the Revillagigedo Islands with broad ridging northwest of there. A relatively tight pressure gradient will yield an increase in winds on both sides of the troughing into the weekend. NW swell will impact waters offshore Baja California this weekend into early next week, leading to seas of 8 to 13 ft north of Cabo San Lazaro by Sun. A broad area of low pressure could form late this week a couple of hundred nautical miles off the coast of southern Mexico or Guatemala. Some slow development is possible this weekend and early next week while the system meanders near the coast. Thunderstorms will impact the waters offshore southern Mexico through the weekend. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Refer to the section above for details on the developing Central American Gyre. The monsoon trough remains located farther north than its usual position for this time of year, and currently extends along the coast of Guatemala then across El Salvador. Moderate southerly winds prevail across area waters. Seas are generally 4 to 7 ft in SW swell, except 3 to 5 ft inside the Gulf of Panama and in the lee of the Galapagos Islands. For the forecast, monsoonal winds, associated seas, and numerous thunderstorms will dominate the region through the end of the week. A broad area of low pressure could form Fri a couple of hundred nautical miles off the coast of southern Mexico or Guatemala. Some slow development is possible this weekend and early next week while the system meanders near the coast. This will allow for the monsoon trough to lift even farther northward toward the Gulf of Tehuantepec, with winds to the west of 90W increasing to fresh to locally strong, leading to building seas of 8 to 12 ft at times, highest late weekend into early next week. Meanwhile, fresh to strong SW winds are expected to develop west of Colombia Fri and shift into the Gulf of Panama Fri night and Sat before diminishing. Seas are likely build to around 8 ft there with these winds. ...REMAINDER OF THE AREA... A surface trough extends from 29N122W to 25N126W with moderate to fresh winds and seas of 7 to 9 ft to the W of it. Otherwise, broad ridging dominates the waters north of the monsoon trough and ITCZ, with mainly gentle winds and 5 to 7 ft seas in mixed swell west of 110W. To the east of 110W, fresh winds are south of the monsoon trough north of 03N, along with seas of 7 to 9 ft. Mainly gentle to moderate winds and 5 to 7 ft seas in S to SW swell are elsewhere east of 110W. For the forecast, strengthening high pressure centered NW of the area will dominate waters west of 120W into the weekend. Fresh to strong winds from the California Channel Islands southward are likely to dip south of 30N at times this weekend into early next week, with seas building to 8 to 13 ft by the end of the weekend. SW flow south of the monsoon trough is forecast to be fresh today between 90W and 110W, supporting seas of 7 to 9 ft. Similar winds and seas are likely to return there by the end of the weekend into early next week. Thunderstorms will persist near the monsoon trough and east of 110W or so through at least the next couple of days. $$ ERA