019 AXPZ20 KNHC 130329 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Wed Nov 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...SPECIAL FEATURES... Excessive Rainfall Risk in Southern Central America: Persistent SW flow in the eastern Pacific region will continue to bring abundant tropical moisture across southern Central America. This combined with a diffluent pattern aloft and the presence of a Central America Gyre (CAG) will increase the likelihood of heavy rainfall across southern Central America through at least the early part of the upcoming weekend. Latest model guidance indicates that the present moderate SW flow offshore Costa Rica and Panama is expected to increase toward the end of the week and into the upcoming weekend as a developing tropical disturbance meanders over the western Caribbean Sea. The abundant tropical moisture is forecast to provide a focus for potentially heavy rainfall to occur in Costa Rica and in western Panama. This information is provided by the Weather Prediction Center's International desk team. Please refer to your national weather agency for details. Large swell over the eastern Pacific: Long-period NW swell is following a now dissipated cold front that moved through the waters north of 20N over the past 24 hours. Wave heights of 12 to 14 ft will impact the waters north of 22N through late today. This will be followed by a reinforcing group of NW swell with wave heights of 12 to 14 ft across the waters north of 20N Thu into Fri, with wave heights to 12 ft persisting in a combination of NW swell and shorter-period NE seas due to trade wind flow from 15N to 20N west of 135W into Sat. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from a 1009 mb low that is located offshore northern Costa Rica near 11N86W, to 1011 mb low pressure near 14N106W, to 1010 mb low near 08N125W. The ITCZ extends from 08N125W to 07N140W. Scattered moderate to isolated strong convection is ongoing from 11N to 15N between 95W and 105W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Moderate to fresh N gap winds persist across the Gulf of Tehuantepec, but these winds are diminishing as the pressure gradient over the region loosens. Farther north, fresh NW winds are spreading across the waters off Baja California associated with high pressure building farther west in the wake of a dissipating cold front that is presently passing across northern Baja California. Mostly gentle to moderate NW to N winds are present elsewhere. Seas are 4-6 ft elsewhere primarily in NW swell, except for lower seas of 2-4 ft in the Gulf of California. For the forecast, large NW swell approaching Guadalupe Island will reach offshore of Cabo San Lazaro by Wed night, and the Revillagigedo Islands by late Thu. A second slightly stronger front will move into the waters of Baja California Norte Fri through Sat. Reinforcing NW swell will follow the front off Baja California Norte Thu night through Sat. Farther south, a cold front moving across the southwestern Gulf of Mexico will bring N gap winds into Gulf of Tehuantepec late Wed through Sat night, reaching at least near- gale force with rough seas Thu through Fri. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please refer to the Special Features section for details on an Excessive Rainfall Risk in Southern Central America. Low pressure of 1009 mb is supporting gentle to moderate SW to W winds and seas to 6 ft along the coasts of Costa Rica and western Panama. Gentle to moderate winds and moderate seas are noted elsewhere. Increasing scattered to numerous showers and thunderstorms are over the offshore waters of Costa Rica and northern Panama. For the forecast, gentle to moderate SW winds will persist across the region through early Thu, then become moderate to fresh off Costa Rica and western Panama by late Thu with little change expected through Sun night. Scattered to numerous showers and thunderstorms offshore Costa Rica and northern Panama are expected to continue through at least the end of the week. Farther north, large northerly swell related to a gap wind event in the Gulf of Tehuantepec will impact the waters off Guatemala beyond 120 nm Fri and Sat. ...REMAINDER OF THE AREA... Please refer to the Special Features sections for details about large swell over the eastern Pacific. Building high pressure over the subtropical eastern Pacific north of 20N is supporting a broad area of moderate to fresh NE to E winds across the region north of 10N and west of 110W. These winds are accompanied by large NW swell described above in the Special Features sections. In addition, Jason-3 altimeter satellite pass indicated seas to 8 ft which cover a region from 07N to 14N between 115W and 125W, associated with mix of swell and shorter-period local wind wave due to fresh NE flow along the monsoon trough, related to a low pressure area that is pulsing along the monsoon trough. Moderate winds and seas are noted elsewhere. Scattered showers and thunderstorms are active along the monsoon trough near a 1011 mb low pressure area near 14N106W. For the forecast, NW long-period swell bringing wave heights of 8-13 ft will cover much of the are north of about 09N and west of 113W going into the early part of the upcoming weekend. Wave heights of 11-14 ft are expected to move into the NW part of the area starting early Thu, shifting eastward to the north- central waters by Fri while slowly subsiding. Looking ahead, high pressure will build north of the area in the wake of a slightly stronger cold front that is forecast to move east-southeastward across the waters north of 20N through Fri. Fresh to strong NE to E winds and additional large NW swell will build across the region north of 10N and east of 110W through Sat. $$ Christensen