000 AXPZ20 KNHC 140321 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Fri Jun 14 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 Heavy Rainfall Event: A Central American Gyre (CAG) is rapidly developing. Heavy rainfall is already occurring. 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 bulletins for more detailed information. ...TROPICAL WAVES... A tropical wave is in the far eastern portion of the tropical eastern Pacific, with axis along 83W from Panama to near 03N, moving west at 5 to 10 kt. Scattered moderate isolated strong convection is noted N of 05N and E of 86W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 12N87W to 16N95W to 15N104W to 07N120W. The ITCZ extends from 07N120W to 10N130W to beyond 10N140W. Scattered moderate and isolated strong convection is noted from 05N to 17N between 78W and 110W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... High pressure centered well NE of the eastern Pacific extends a ridge southeastward 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 eastern coast of the Baja California peninsula. Moderate winds are in the northern and southern Gulf of California, with light and variable winds in the central 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 N of 15N. Seas in this area range 4 to 6 ft within mixed swell. The monsoon trough has lifted north around 15N, which is bringing moderate to fresh SW winds to portions of the southern Mexico offshore waters. Seas have increased to 6 to 8 ft in these winds within S to SW swell. Thunderstorms persist across the waters south of 17N and east of 104W. Across most of the Mexico offshore waters, smoke from agricultural fires may be restricting visibility somewhat over area waters. For the forecast, a relatively tight pressure gradient between troughing over Mexico and ridging NW of the area will bring an increase in winds off the Baja California coast into the weekend. NW swell will impact waters offshore Baja California this weekend into early next week, leading to seas of 8 to 12 ft north of Cabo San Lazaro by Sun into Mon. A broad area of low pressure located a few hundred miles southwest of Acapulco, Mexico, is producing disorganized showers and thunderstorms. Some slow development is possible this weekend and early next week while the system moves slowly ESE. This system has a low chance of formation over the next 7 days. ...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, extending along the coast of Guatemala then across El Salvador. Moderate to fresh southerly winds prevail across the Central American and Colombia offshore waters. Seas are generally 4 to 7 ft in SW swell in this area. In the Ecuador and Galapagos Island offshore waters, winds are gentle to moderate with 4 to 6 ft seas within SW swell. For the forecast, monsoonal winds, associated seas, and numerous thunderstorms will dominate the region through the weekend. A broad area of low pressure located a few hundred miles southwest of Acapulco, Mexico, is producing disorganized showers and thunderstorms. Some slow development is possible this weekend and early next week while the system moves slowly ESE. This system has a low chance of formation in the next 7 days. Regardless of development, this will allow for the monsoon trough to remain well north of the area. Winds west of 90W increasing to fresh to strong, leading to building seas of 8 to 12 ft at times, later this weekend into early next week. Heavy rainfall will also impact portions of Central America through the weekend. 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... Broad ridging dominates the waters north of the monsoon trough and ITCZ, with gentle to moderate winds and 5 to 8 ft seas in mixed swell west of 115W. To the east of 115W, moderate to locally fresh winds are south of the monsoon trough north of 04N, along with seas to 8 ft. Mainly gentle to moderate winds and 5 to 7 ft seas in S to SW swell are elsewhere east of 115W. 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 12 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 the next couple of days. $$ AReinhart